# First threads!



## DavidR8

I had a few minutes today so I tried my hand at single point threading. 
I wanted everything to happen slowly so I put the lathe in back gear and chose 10 TPI so I could see what was going on. 
Had a spare piece of aluminum of no particular diameter and went for it. 
Turned out spot on according to my thread checker. 
The finish is crap because it was low speed on aluminum but I am quite thrilled because I didn’t crash and hit the mark on the thread dial every time. 
I’m not sure why the first couple of threads look so crummy when the balance look semi-ok. 

I got a bit muddled when I didn’t count my turns back out on the cross slide so I just went to the end and put the tool against the work and reset to zero and backed out again. 








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## francist

Good for you, I was wondering when that was going to occur!

I remember the first time I cut a thread — I must have done dry runs for about a week. At the lathe, sitting at my desk at work, watching tv, all the time working the sequence in my head and moving my hands. Still sweated like crazy the first time for real though!

 Now — inside, outside, left hand right hand, whatever. Still want to try multi-start though, just to see it work.

Good job, David 

-frank


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## brino

Those look better than my first threads!
Good job David!

-brino


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## DavidR8

Thanks Frank, I’ve been doing exactly the same thing, rehearsing the moves. 
I stood in front of the lathe for 15-20 minutes with it running doing all the movements running up to a magnet I put on the ways as a marker. 


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## DavidR8

brino said:


> Those look better than my first threads!
> Good job David!
> 
> -brino



Thanks!
I’m pretty stoked. Feels like a major step for some reason. 


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## eugene13

DavidR8 said:


> Thanks!
> I’m pretty stoked. Feels like a major step for some reason.
> 
> 
> Sent from my iPhone using Tapatalk


It is a major step, you have every tight to feel stoked.


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## John O

Better than my first time and I can still screw them up with out a problem.


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## Aukai

Nice, I almost had a good one, but my brain disconnected, and missed the engagement


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## BGHansen

Nice job!  Now comes thread wires and/or pitch micrometers! Also, insert tooling with boring bars for internal threading. 

Bruce


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## DavidR8

Thanks guys, I wouldn't be here able to do this halfway right if it weren't for the encouragement and guidance from you good folks.


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## mickri

I used PVC pipe fittings to practice with when I started.  Painted it red with a sharpe.  The color gives you a visual reference.  When the color is gone the thread should be done.  The color really helps with internal threads.  I still color whatever I am threading.  With internal threading I like doing it with the tool bit on the backside because the motion/hand movements are the same as with external threading.

What were you referring to when you mentioned counting turns.  When I am threading I touch the work using the cross slide and set the cross slide to zero.  I also zero the compound.  My depth of cut is with the compound.  The compound is never backed out.  Only the cross slide.  The sequence I use is to engage the half nuts.  Make the cut and disengage the half nuts at the end of the thread.  Then I back out the cross slide and return the carriage to the starting point.  Next I return the cross slide to zero and advance the compound a couple of thousands.  Engage the half nuts for another pass.  Do this over and over until the thread is done.

Another handy skill is to be able to pick up a thread.  Mr Pete has a good video on picking up a thread.  And then you have metric threading.  The fun and the learning never stops.

Congrats on your successful thread.


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## mikey

There are milestones for hobby guys, Dave, and you just passed a big one on your first try - way to go!!! From here on, it's just practice and things will improve quickly. First times for anything is special; glad you shared this one with us.


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## DavidR8

mickri said:


> I used PVC pipe fittings to practice with when I started.  Painted it red with a sharpe.  The color gives you a visual reference.  When the color is gone the thread should be done.  The color really helps with internal threads.  I still color whatever I am threading.  With internal threading I like doing it with the tool bit on the backside because the motion/hand movements are the same as with external threading.
> 
> What were you referring to when you mentioned counting turns.  When I am threading I touch the work using the cross slide and set the cross slide to zero.  I also zero the compound.  My depth of cut is with the compound.  The compound is never backed out.  Only the cross slide.  The sequence I use is to engage the half nuts.  Make the cut and disengage the half nuts at the end of the thread.  Then I back out the cross slide and return the carriage to the starting point.  Next I return the cross slide to zero and advance the compound a couple of thousands.  Engage the half nuts for another pass.  Do this over and over until the thread is done.
> 
> Another handy skill is to be able to pick up a thread.  Mr Pete has a good video on picking up a thread.  And then you have metric threading.  The fun and the learning never stops.
> 
> Congrats on your successful thread.


I lost track when backing the cross slide out. The first couple of passes it didn't take much to back away from the work but when I had to retract more than a a couple of thou I lost track of whether I passed zero or not. So when I went to zero, I was only a few tenths away from zero so I assumed (correctly) that I had gone once around the dial plus a few more. 
What I started to do was crank back one revolution and that got me unmuddled.
(not sure that makes any kind of sense...)

Thinking about it more, I now realize that the nerve-wracking part is the cutting part, once the half-nuts are released there's no more "OMG, it's going to crash" panic, so there no reason I can't look down at the cross slide dial and watch what I'm doing.


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## DavidR8

mikey said:


> There are milestones for hobby guys, Dave, and you just passed a big one on your first try - way to go!!! From here on, it's just practice and things will improve quickly. First times for anything is special; glad you shared this one with us.


Thanks Mike, wouldn't be here without all of you   

I brought the piece inside and showed it to my partner and she exclaimed "You made that? Babe that's awesome!"

She's the literal best.


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## Lonnie

Congrats David!
Those look a whole lot better than my first attempt.


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## Downunder Bob

Well done Dave It's a major milestone for all of us. watch some u tubes by Joe Pie he has some great tips on threading and just about everything else.


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## DavidR8

Oh jeepers! I forgot to set the compound to 29.5 degrees!!!
It was set to 23 degrees. 
What impact would that have had on the operation?


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## higgite

Good job on your first thread. Don’t sweat the appearance of the first couple of threads in the pic unless it continues to show up when you cut more threads. Another thing to consider is the tool needs to really be sharp on both edges, leading and trailing, especially when threading aluminum at such a slow speed.

Regarding losing track of how far you backed the cross slide out, FWIW, I’ve developed the habit of backing it out 2 full turns and stopping close to but not on the zero mark. Two turns on my cross slide is .200”, which is more than enough to back out of any thread that I’m likely to cut, and not stopping on zero is an indicator to me that I haven’t cranked it back in for the next pass if I happen to forget whether I cranked it back in or not for the next pass. That has happened to me when I broke my rhythm to measure the thread or test it with a nut. You’ll pick up your own little tricks like that as you go.

Tom


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## higgite

I just saw your last post. That will definitely screw up a thread. (pun intended)  Although, more than 30 degrees is much worse. Was that 23 degrees from parallel with the spindle axis or 23 degrees from perpendicular to the spindle axis. If the former, that is really bad news for threading. That might explain the first couple of threads.

Tom


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## DavidR8

Thanks @higgite, I like the idea of picking a set number of turns to back out the cross slide. Seems it would lead to less confusion. 

It was 23 degrees from perpendicular to the centre line of the spindle. 

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## higgite

DavidR8 said:


> Thanks @higgite, I like the idea of picking a set number of turns to back out the cross slide. Seems it would lead to less confusion.
> 
> It was 23 degrees from perpendicular to the centre line of the spindle.
> 
> Sent from my iPhone using Tapatalk


You want it 29.5 degrees from perpendicular to the spindle axis. That's why your threads look like they do. A common mistake for newcomers to threading. They hear 29.5 degrees and set the compound by the protractor on their machine which usually indicates degrees from parallel with the spindle axis. Don't ask me how I know that. 

Tom


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## DavidR8

Thanks Tom, I’m going to retry tomorrow with the compound at the correct angle. 
Really appreciate everyone’s advice. 


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## ttabbal

Looks like you're getting going.  

Don't tell anyone, but I'm one of those crazy people who don't thread with the compound... Lol.. In part due to having it removed most of the time and not wanting to bother reinstalling it.


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## mikey

ttabbal said:


> Looks like you're getting going.
> 
> Don't tell anyone, but I'm one of those crazy people who don't thread with the compound... Lol.. In part due to having it removed most of the time and not wanting to bother reinstalling it.



Hah, I was going to say you took it off and lost it!


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## ttabbal

mikey said:


> Hah, I was going to say you took it off and lost it!



Hey now! I'm, like, 90% sure where it is!


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## Downunder Bob

When I was an apprentice we were not allowed to set the compound slide to any angle but square to the lathe except when we were turning a feature that had an angle, but absolutely not for threading

Oh, we knew the procedure existed, and once we had perfected screwcutting, we were then allowed to use it.

The training was hard, but in the end we were pretty good at what we did, because we not only knew how to do it, but why.


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## Janderso

Good for you David,
You’re getting to know your lathe.


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## HarryJM

As they say "practice makes perfect" so keep at it!


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## brino

DavidR8 said:


> Oh jeepers! I forgot to set the compound to 29.5 degrees!!!
> It was set to 23 degrees.
> What impact would that have had on the operation?



Your threads may not be 60 degrees, but no matter, you were practicing the operation.
Besides it sounds like you cut it at a random diameter, so you were never going to check it with a nut anyway!
It is still a win!

One thing that might make the next one easier.....
Cut a groove near the end where you finish the threads. It's a place to temporarily park the cutter at the end of cut when you disengage the half-nuts.
Make it about ~2 threads wide, and it takes away some of the panic at the end.

-brino


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## Liljoebrshooter

The angle of the compound will not effect the threads if you are feeding with the cross slide only.  It will when using the compound.  Yep, I know that from experience.
Looking good Dave.
Another tip is to cut a finer pitch thread.  The carriage is moving a lot slower.  Try cutting a 20 tpi and see the difference.
I use a dial indicator on the carriage to measure when you are nearing the end of the thread.
Joe Hynes


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## devils4ever

Very nice for your first thread. My first attempt was nowhere as good. I had the compound set to the wrong angle and had other issues.

I agree with Liljoebrshooter. Cutting finer threads is less stressful on you and your lathe.

And definitely cut a gutter or groove to end your cut. Much less stress that way.


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## T Bredehoft

Assuming your tool is 60º, and your are between 29.5 and 0 to the work, your thread should be fine. In that angle range, its the tool, not the angle that makes the thread.


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## SLK001

brino said:


> Your threads will not be 60 degrees, but no matter, you were practicing the operation.



The thread angle depends entirely on your cutting tool, not the angle of your compound.  Having the compound at angles other than 29.5º or 30º just means more stress on the tool, which leads to nastier looking threads.




DavidR8 said:


> I had a few minutes today so I tried my hand at single point threading.



That's quite a milestone.  It really wasn't as hard as you imagined, was it?  Please explain your setup.



> Turned out spot on according to my thread checker.



Explain how you checked your thread.  What was your goal?  Did you use the three wire method, or a thread micrometer?  Cutting a thread is easy... Getting it correct, not so much.



> I’m not sure why the first couple of threads look so crummy when the balance look semi-ok.



No support at the end.  Center drill the end and use a center to increase the rigidity of your work.  Also, aluminum isn't a very good material for your first threads, because a lot of grades of it are too gummy.  Use some scrap steel stock (with a good cutting lube, like Oakleys).  You also shouldn't be turning to a shoulder.  Turn a flat area beyond your thread area and practice with that.



> I got a bit muddled when I didn’t count my turns back out on the cross slide so I just went to the end and put the tool against the work and reset to zero and backed out again.



I use a pencil to mark a line on the cross slide where the compound sits, topped with a "V" to indicate the correct zero starting point.  Don't depend on yourself counting the turns correctly in the heat of battle.  At the end, it easily wipes off.


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## DavidR8

SLK001 said:


> The thread angle depends entirely on your cutting tool, not the angle of your compound.  Having the compound at angles other than 29.5º or 30º just means more stress on the tool, which leads to nastier looking threads.
> 
> That's quite a milestone.  It really wasn't as hard as you imagined, was it?  Please explain your setup.
> 
> Explain how you checked your thread.  What was your goal?  Did you use the three wire method, or a thread micrometer?  Cutting a thread is easy... Getting it correct, not so much.
> 
> No support at the end.  Center drill the end and use a center to increase the rigidity of your work.  Also, aluminum isn't a very good material for your first threads, because a lot of grades of it are too gummy.  Use some scrap steel stock (with a good cutting lube, like Oakleys).  You also shouldn't be turning to a shoulder.  Turn a flat area beyond your thread area and practice with that.
> 
> I use a pencil to mark a line on the cross slide where the compound sits, topped with a "V" to indicate the correct zero starting point.  Don't depend on yourself counting the turns correctly in the heat of battle.  At the end, it easily wipes off.


Hmmm my setup, I used a threading insert, ran in back gear because I wanted it to go slowly till I had some sense of what was going on. 
The usual, scratch pass, back out wheel back to the start, rinse and repeat. 

When I say I checked my thread, I mean that it matched the pitch. It was looking sketchy when I started for some reason, almost like I didn't hit my mark on the threading dial and did the second pass off-pitch if that pakes sense.

Thanks for the tips, I'll give them a whirl. Maybe today I can give it another go.


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## higgite

SLK001 said:


> The thread angle depends entirely on your cutting tool, not the angle of your compound.


I respectfully disagree. If the compound angle is set to more than 30 degrees from perpendicular to the spindle axis, it will definitely affect the shape and finish of the thread. See this old thread. (no pun intended) https://www.hobby-machinist.com/threads/threading-help.49488/#post-416870

Tom


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## mickri

I use pencil marks too for a quick reference.  Not only for threading but also for boring.  For threading I mark the cross slide.  I also have a stop for the cross slide that I sometimes use.  Back the cross slide out as far as you want to.  Then move it in until it hits the stop.  For boring I make a mark on the bed that will line up with a wiper at the end of the cut.  This just a visual aid.  If I have to have precision I use a carriage stop.


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## ErichKeane

One thing I'd suggest (since you didn't say it!), I set up dial indicators EVERYWHERE when I'm cutting threads!  The dials are nice, but are no replacement for a good dial indicator.

First, put one on your ways against the carriage, this makes it WAY easier to 'stop' at the right place.  I haven't had GREAT luck with cutting threads without the undercut (where the thread 'just stops'), but this indicator gives me the best results.

Second I put one on my cross-slide ways against the cross-slide.  This allows me to make sure I get back to my zero spot, because messing this up even just a little can bisect/mess up threads pretty bad.  I have actually discovered that I have a thread stop, so I used that the last time instead with good results.

Third, from the cross-slide to the compound (against a flat surface) measuring perpendicular to the ways.  This gives you a great idea about the depth of cut and total depth of cut.  The nice part is that this isn't susceptible to any other movements.

Another thing I'll suggest: HSS.  Grab some bits and grind them.  When I first started cutting threads, I did the Carbide inserts, however the instant I switched to HSS my cuts improved 10 fold.  HSS has 3 advantages:
1- You can make them sharper than the carbide since you're grinding them yourself!  This gives you a better chance against chatter.
2- HSS normally runs at about 40% of the RPMs of carbide.  This means you can run the spindle at a much slower speed.  I personally thread cut at my lathe's slowest speed when I can for exactly this reason!
3- HSS is WAY more tolerant of being run at below its speeds/feeds.  Carbide I found wants to be at a specific RPM, HSS is much more forgiving.


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## BrentH

@DavidR8 Have a read of this:  https://rick.sparber.org/spt.pdf

It will explain how the set up at 29.5 degrees is critical to keeping your threading tool cutting on the right path and developing the root of the thread.

if you have a good threading alignment gauge it will also have depths of cut for the different pitches on the gauge:


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## DavidR8

ErichKeane said:


> One thing I'd suggest (since you didn't say it!), I set up dial indicators EVERYWHERE when I'm cutting threads!  The dials are nice, but are no replacement for a good dial indicator.
> 
> First, put one on your ways against the carriage, this makes it WAY easier to 'stop' at the right place.  I haven't had GREAT luck with cutting threads without the undercut (where the thread 'just stops'), but this indicator gives me the best results.
> 
> Second I put one on my cross-slide ways against the cross-slide.  This allows me to make sure I get back to my zero spot, because messing this up even just a little can bisect/mess up threads pretty bad.  I have actually discovered that I have a thread stop, so I used that the last time instead with good results.
> 
> Third, from the cross-slide to the compound (against a flat surface) measuring perpendicular to the ways.  This gives you a great idea about the depth of cut and total depth of cut.  The nice part is that this isn't susceptible to any other movements.
> 
> Another thing I'll suggest: HSS.  Grab some bits and grind them.  When I first started cutting threads, I did the Carbide inserts, however the instant I switched to HSS my cuts improved 10 fold.  HSS has 3 advantages:
> 1- You can make them sharper than the carbide since you're grinding them yourself!  This gives you a better chance against chatter.
> 2- HSS normally runs at about 40% of the RPMs of carbide.  This means you can run the spindle at a much slower speed.  I personally thread cut at my lathe's slowest speed when I can for exactly this reason!
> 3- HSS is WAY more tolerant of being run at below its speeds/feeds.  Carbide I found wants to be at a specific RPM, HSS is much more forgiving.


Thanks @ErichKeane, I plan to grind an HSS tool. This was really a "I have some spare time, let's see if I can do this from memory" 
One of my first mill projects will be a carriage stop. 
I'm having trouble picturing a cross slide indicator mount. Can you post a pic of yours?


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## ErichKeane

DavidR8 said:


> Thanks @ErichKeane, I plan to grind an HSS tool. This was really a "I have some spare time, let's see if I can do this from memory"
> One of my first mill projects will be a carriage stop.
> I'm having trouble picturing a cross slide indicator mount. Can you post a pic of yours?


I'm not out in the shop today, but I usually just put a magnetic back dial indicator on the ways (it helps that I have pretty giant ways since it is a big lathe).  however, I found this one: https://www.homemodelenginemachinist.com/attachments/crossslideindicator-jpg.34673/
I wouldn't bother with the 2nd piece of metal and just indicate directly against the slide itself.

I put mine on the 'operator' side right up against the front of the cross-slide, but I have quite a bit of the cross-slide ways visible when cutting.  On bigger ones, I use a dial indicator on a mag-base and put it on the top of the apron (off to the side).


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## SLK001

higgite said:


> I respectfully disagree. If the compound angle is set to more than 30 degrees from perpendicular to the spindle axis, it will definitely affect the shape and finish of the thread.



Okay, I'll concede your point and say that only the portion of the cut of the last pass will have a 60º included angle.  But I would also say that for any angle on the compound greater than 30º (for a 60º thread) that you aren't cutting a thread.


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## mickri

Here's my cross slide stop


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## DavidR8

BrentH said:


> @DavidR8 Have a read of this:  https://rick.sparber.org/spt.pdf
> 
> It will explain how the set up at 29.5 degrees is critical to keeping your threading tool cutting on the right path and developing the root of the thread.
> 
> if you have a good threading alignment gauge it will also have depths of cut for the different pitches on the gauge:
> 
> View attachment 319819


Ok I think I know how I messed up. Last night, Tom (@higgite) asked me if my coumpound was "23 degrees from parallel with the spindle axis or 23 degrees from perpendicular to the spindle axis?"

I mistakenly said from perpendicular to the spindle axis.
This is how its set.


(An artist I am not!)

I now realize that I needed to be 59 degrees using this point of reference or 29.5 degrees measuring from a line perpendicular to the work.
I see the the intent is for the compound to be inline with the right side of the eventual thread. Thanks for the reference to Rick Sparber @BrentH, that made it click into place. Doh!


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## SLK001

If that is how you had your setup, then you didn't move the compound, just the cross slide.  If you just move the cross slide, it really doesn't matter what your compound angle is set at.

Your drawing can't possibly cut that thread above if you moved the compound.  But it can only moving the cross slide.


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## DavidR8

SLK001 said:


> If that is how you had your setup, then you didn't move the compound, just the cross slide.  If you just move the cross slide, it really doesn't matter what your compound angle is set at.
> 
> Your drawing can't possibly cut that thread above if you moved the compound.  But it can only moving the cross slide.


I used the cross slide to back in and out of the work and advanced the compound to increase the DoC.


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## SLK001

A South Bend compound is marked in degrees perpendicular to the work axis.  Zero degrees is exactly perpendicular to the work axis and 90º is exactly parallel to the work axis.  If you had the compound set to 23º, then it was 23º off perpendicular to the work, which will cut a thread.  However, your drawing above shows an angle greater than 30º, which will NOT cut a thread.


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## francist

DavidR8 said:


> now realize that I needed to be 59 degrees using this point of reference or 29.5 degrees measuring from a line perpendicular to the work.


The classic mistake. Aside from all the number and degree referencing this is one time when a good visual recognition is invaluable. “Does this Vee look right to me?”  
Don’t worry, you’ll get it 

-f


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## DavidR8

SLK001 said:


> A South Bend compound is marked in degrees perpendicular to the work axis.  Zero degrees is exactly perpendicular to the work axis and 90º is exactly parallel to the work axis.  If you had the compound set to 23º, then it was 23º off perpendicular to the work, which will cut a thread.  However, your drawing above shows an angle greater than 30º, which will NOT cut a thread.


I don't know what to say other than that is exactly how it was and is still set. 
Pics for clarity.
Overall view of the setup.



Protractor laid against compound and against chuck.



Resulting angle.


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## Nigel123

DavidR8 said:


> I don't know what to say other than that is exactly how it was and is still set.
> Pics for clarity.
> Overall view of the setup.
> View attachment 319871
> 
> 
> Protractor laid against compound and against chuck.
> View attachment 319873
> 
> 
> Resulting angle.
> View attachment 319875


Looks to me like you are about 30 degrees off
I think you should be at 119 degrees on your setup
Your compound feed should almost parallel the angle of the thread


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## DavidR8

Nigel123 said:


> Looks to me like you are about 30 degrees off
> I think you should be at 119 degrees on your setup
> Your compound feed should almost parallel the angle of the thread


Yup, that's what I've discovered


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## Liljoebrshooter

Here is how I use an indicator to set my depths into a hole or up to a shoulder. When you are cutting a 18tpi thread or as smaller, its pretty easy to stop within a couple thousandths.  It only goes around the dial about 1/2 of a revolution so you don't have to count.
Joe Hynes


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## DavidR8

So I tried more threading tonight.
Some 5/8" cold rolled, tried a 32 tpi thread. I definitely need to grind a proper HSS bit as the carbide insert doesn't like the low speed that I'm comfortable with.
All in service of learning though, I absolutely love doing this stuff!


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## Z2V

You will be cutting internal threads real soon!!


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## DavidR8

Z2V said:


> You will be cutting internal threads real soon!!


Thanks @Z2V, it feels like I'm almost part of the club!


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## Z2V

Ah David, your in for sure. Your enthusiasm is exciting.
Cutting threads was one of the first things I wanted to learn when I got my first little lathe.
I must have made a few dozen of these captive nut thingies. Fine thread, coarse thread, left hand, right hand, metric, etc.
My biggest problem was trying to use the thread wires as my left hand was severed years ago so I don’t have full dexterity there. @mikey suggested a thread mic, I haven’t touched the wires since.
Yea, internal threads are a whole new challenge, a fun one also.


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## DavidR8

Z2V said:


> Ah David, your in for sure. Your enthusiasm is exciting.
> Cutting threads was one of the first things I wanted to learn when I got my first little lathe.
> I must have made a few dozen of these captive nut thingies. Fine thread, coarse thread, left hand, right hand, metric, etc.
> My biggest problem was trying to use the thread wires as my left hand was severed years ago so I don’t have full dexterity there. @mikey suggested a thread mic, I haven’t touched the wires since.
> Yea, internal threads are a whole new challenge, a fun one also.
> View attachment 319978


Awww thanks man 
I'm a ways away yet but that's what I want to make for my step-son!!!


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## mikey

DavidR8 said:


> I definitely need to grind a proper HSS bit as the carbide insert doesn't like the low speed that I'm comfortable with.
> All in service of learning though, I absolutely love doing this stuff!



Yes, go grind a good tool. I promise you that it will be worth it. A HSS tool will cut much cleaner at the low speeds you're working with.

Let me give you some advice on grinding that tool. You know that when orienting the tool to the work we usually use the fishtail gauge to do it. You have to futz with the fishtail while aligning the tool post so the tip of the threading tool sits perfectly in the 60 degree cutout. This is a major pain. The way I get around that is to use a protractor and mark out the 30 degree angle on the left side of the tool using the shank of the tool as a reference upon which the protractor sits. If you grind that first angle at exactly 30 degrees and then match the second 30 degree angle on the right side of the tool accurately, you can just use the shank of the tool as a reference and never even bother with the fishtail to align the tool. You just need a piece of stock that is faced on both ends. Place one end of the stock on the face of the chuck and the shank of your threading tool on the other end of the stock and you're aligned. Takes seconds to do, and it will be accurate. 

Jeff is right. Look into a thread mic. It will save what hair you have left if you don't have to go searching for the thread wire you WILL drop in the chip pan.


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## DavidR8

mikey said:


> Yes, go grind a good tool. I promise you that it will be worth it. A HSS tool will cut much cleaner at the low speeds you're working with.
> 
> Let me give you some advice on grinding that tool. You know that when orienting the tool to the work we usually use the fishtail gauge to do it. You have to futz with the fishtail while aligning the tool post so the tip of the threading tool sits perfectly in the 60 degree cutout. This is a major pain. The way I get around that is to use a protractor and mark out the 30 degree angle on the left side of the tool using the shank of the tool as a reference upon which the protractor sits. If you grind that first angle at exactly 30 degrees and then match the second 30 degree angle on the right side of the tool accurately, you can just use the shank of the tool as a reference and never even bother with the fishtail to align the tool. You just need a piece of stock that is faced on both ends. Place one end of the stock on the face of the chuck and the shank of your threading tool on the other end of the stock and you're aligned. Takes seconds to do, and it will be accurate.
> 
> Jeff is right. Look into a thread mic. It will save what hair you have left if you don't have to go searching for the thread wire you WILL drop in the chip pan.


Ahhh that's a great tip on tool alignment. I used a 1-2-3 block tonight to make sure the tool was perpendicular to the work.

I added a set of thread wires to my KBC cart today. Do you have a preferred thread mic?


----------



## Z2V

I bought this one from Amazon. Naturally, there are more expensive, higher quality thread mics out there but this works just fine for me for the work I’m doing.


----------



## DavidR8

Z2V said:


> I bought this one from Amazon. Naturally, there are more expensive, higher quality thread mics out there but this works just fine for me for the work I’m doing.
> View attachment 319981


Thanks! that was the exact model I was looking at. Saved $18 on shipping


----------



## mikey

I think the Accusize and Shars mics are identical; so is the price. They should work just fine.

Hate to tell you guys that I paid just a bit more for my Tesa 0-1 and 1-2 thread mics than it would cost for the imports. Yeah, I'm bragging! Right place, right time, mad eBay skills ...


----------



## ttabbal

mikey said:


> I think the Accusize and Shars mics are identical; so is the price. They should work just fine.
> 
> Hate to tell you guys that I paid just a bit more for my Tesa 0-1 and 1-2 thread mics than it would cost for the imports. Yeah, I'm bragging! Right place, right time, mad eBay skills ...


----------



## DavidR8

Well done @mikey, yes the usual admonitions apply as @ttabbal brought forward in a timely fashion.
I was looking at the Mitu mics and promptly fell of the sofa.


----------



## Z2V

Yea, you do have eBay figured out.


----------



## tmenyc

David, 
I love your progress, which in some ways mirrors mine, although you're more adventurous in big gulps than I.  
I'm hoping you won't mind my joining your thread here, no pun intended, but my issues are square in the same subject. My threading is also getting a lot better, using HSS on 12L14.  I had good success this past weekend with 1/2-20 and then 5/16-18.  Didn't, of course, have a nut to match to the 1/2-20 (duh...), but did for the 5/16-18 (top picture is Home Depot nut/bolt.  Got very close to finished, measured with wires, and then lost track of my cross-slide location and couldn't get it back right, so it got messed up.  
I definitely have the litany of threading down, and it's fun.



The main issue I'm having now is real estate, my eventual goal being making small threads on soft material. I'm working towards the headstock, with a dead center holding things still, and there just isn't enough space to hold the work and position the tool; particularly so when using the wires...there's just no room for both of my hands, the wires, and a micrometer!  I think I need to have more centered length, with the threaded portion somewhere in the middle, and a relief groove at both ends.  I'm quite comfortable working in close to the chuck at these speeds, at least so far.  
Any comments or tips would, of course, be appreciated.  Looking forward to my next session, probably next weekend.
Thanks!
Tim


----------



## BGHansen

I have a couple sets of Shars 0-1" and 1"-2" thread mics and one 2"-3" set.  I have an abbreviated chart showing the pitch diameters of common threads setting in the micrometer cases (thread below has a pic).  I have no idea where my thread wires are since I picked up the thread mics.  One thing of note on the mics is they are specifically for 60 deg. threads.  You can't use them on Acme threads, thread wires would be your best option there.

Bruce










						Thread depth
					

How do you calculate the compound depth for a given pitch? Trying to figure out the calculation is kicking my ass.




					www.hobby-machinist.com


----------



## macardoso

@DavidR8, Awesome job! You are making some real progress forward. 

The 29.5 degree angle thing gets a lot of rookies on their first time (myself included). I prefer to skip the compound angle and thread with the cross slide only. It saves time and I haven't seen any difference in the quality of cut between the two. Plus it makes it much easier to advance on the diameter directly (skipping the trig for the compound slide). Try it out at some point and make a decision which you like better. 

I do almost all my threading with carbide (and turning too!). There is not really a minimum speed limit for carbide, the big difference is the maximum speed you can cut. If you find carbide is not working well for a particular application, you may want to look for a sharper insert with a ground edge. These are often advertised as being for aluminum but they work very well on soft steels and stainless as well. I see it is easy to find the 16ER insert with this edge geometry, although I haven't tried them personally yet.

Soft metals like aluminum, 1018, etc don't like to make pretty threads in my experience. Try picking up some 41L40 and threading on that. You'll be amazed at how professional your work will look.

I usually use the threading tool to create a relief behind the thread I am about to cut (about a thou or two below the full depth of cut). This gives you room to disengage the half nuts. 

Thread mics are great and very fast, however you should pick up a cheap set of thread wires and get used to using them. You can use them for any diameter thread and any pitch. They will get you out of a tough spot where you can't use the mic.

Thread tables are my most used chapter of Machinery's Handbook. I use these to copy the major diameter and pitch diameter tolerance range to my notebook before heading to the lathe. I also use this website frequently to calculate the tolerances of threads that aren't in Machinery's Handbook: http://theoreticalmachinist.com/Threads_UnifiedImperial.aspx

Keep up the great work!


----------



## T Bredehoft

Thread wires can be handled. stick the ends ot the three wires in a Styrofoam peanut.


----------



## deakin

a friend in manufacturing gave me a metal chart i attached to my engine lathe that shows tpi, single cut (straight infeed) and 30 degree infeed dimensions. it's always worked for what i do. his co doesn't use wires, etc but they do use a series of thread gauges for inspection. i guess per iso they have to replace those regularly so i have a set but rarely use them


----------



## macardoso

deakin said:


> a friend in manufacturing gave me a metal chart i attached to my engine lathe that shows tpi, single cut (straight infeed) and 30 degree infeed dimensions. it's always worked for what i do. his co doesn't use wires, etc but they do use a series of thread gauges for inspection. i guess per iso they have to replace those regularly so i have a set but rarely use them



Those are incredible you expensive to put a set together. You’re lucky!


----------



## DavidR8

macardoso said:


> @DavidR8, Awesome job! You are making some real progress forward.
> 
> The 29.5 degree angle thing gets a lot of rookies on their first time (myself included). I prefer to skip the compound angle and thread with the cross slide only. It saves time and I haven't seen any difference in the quality of cut between the two. Plus it makes it much easier to advance on the diameter directly (skipping the trig for the compound slide). Try it out at some point and make a decision which you like better.
> 
> I do almost all my threading with carbide (and turning too!). There is not really a minimum speed limit for carbide, the big difference is the maximum speed you can cut. If you find carbide is not working well for a particular application, you may want to look for a sharper insert with a ground edge. These are often advertised as being for aluminum but they work very well on soft steels and stainless as well. I see it is easy to find the 16ER insert with this edge geometry, although I haven't tried them personally yet.
> 
> Soft metals like aluminum, 1018, etc don't like to make pretty threads in my experience. Try picking up some 41L40 and threading on that. You'll be amazed at how professional your work will look.
> 
> I usually use the threading tool to create a relief behind the thread I am about to cut (about a thou or two below the full depth of cut). This gives you room to disengage the half nuts.
> 
> Thread mics are great and very fast, however you should pick up a cheap set of thread wires and get used to using them. You can use them for any diameter thread and any pitch. They will get you out of a tough spot where you can't use the mic.
> 
> Thread tables are my most used chapter of Machinery's Handbook. I use these to copy the major diameter and pitch diameter tolerance range to my notebook before heading to the lathe. I also use this website frequently to calculate the tolerances of threads that aren't in Machinery's Handbook: http://theoreticalmachinist.com/Threads_UnifiedImperial.aspx
> 
> Keep up the great work!


Thanks, I'm going to keep at it because this is a skill I want to develop. So definitely open to all information and perspectives. 
It's completely mesmerizing to watch the tool make its way along the work, a chip curling off and at the end of it you have a useful part.
Amazing!


----------



## SLK001

The leaded steel cuts very nice (that's what the "L" in the designation means).  South Bend used a lot of leaded material for that reason.  

As for the 0º vs 29.5º-30º argument, the 30º approach puts less cutting stress on the tool (it only cuts on the leading edge).  Less stress usually means a better looking thread.  Anyway, I usually clean up my threads with a couple of high speed passes with a triangular file to clean up the flanks of the thread, then a flat mill file to clean up the tops.  

I have a 0-1" thread mike that is really, really useful.  I plan on getting both a 1"-2" and a 2"-3", but right now, I use wires for those.


----------



## DavidR8

Alrighty folks, 
A bit more lathe time tonight. 
Having had my fill of CRS I tried some 10L. 
Cut off a chunk, faced it off, took .010 off the diameter. 






Cut a gutter and blued it up. 





Picked 16 TPI as my pitch, put it in back gear and took a scratch pass. 





Pretty darn happy with the results. 





Buoyed by my success I turned a piece of CRS to the major diameter for 3/8” and repeated the process. 





The results speak for themselves. 





I am stoked!


Sent from my iPhone using Tapatalk


----------



## DavidR8

SLK001 said:


> The leaded steel cuts very nice (that's what the "L" in the designation means). South Bend used a lot of leaded material for that reason.
> 
> As for the 0º vs 29.5º-30º argument, the 30º approach puts less cutting stress on the tool (it only cuts on the leading edge). Less stress usually means a better looking thread. Anyway, I usually clean up my threads with a couple of high speed passes with a triangular file to clean up the flanks of the thread, then a flat mill file to clean up the tops.
> 
> I have a 0-1" thread mike that is really, really useful. I plan on getting both a 1"-2" and a 2"-3", but right now, I use wires for those.



I just bought a 0-1” thread mic last night! 

I turned some 10L tonight for the second time. What a dream that is compared to CRS!


Sent from my iPhone using Tapatalk


----------



## Nigel123

SLK001 said:


> The leaded steel cuts very nice (that's what the "L" in the designation means).  South Bend used a lot of leaded material for that reason.
> 
> As for the 0º vs 29.5º-30º argument, the 30º approach puts less cutting stress on the tool (it only cuts on the leading edge).  Less stress usually means a better looking thread.  Anyway, I usually clean up my threads with a couple of high speed passes with a triangular file to clean up the flanks of the thread, then a flat mill file to clean up the tops.
> 
> I have a 0-1" thread mike that is really, really useful.  I plan on getting both a 1"-2" and a 2"-3", but right now, I use wires for those.


I have cut numerous threads without thread gauges using the no of threads divided into 0.75 or 0.742 for the infeed of the compound
I use HSS cutter the threads are smooth no filing needed
Use cutting oil and a couple of spring passes
I use 29.5 degrees as it only cuts mostly on the leading edge
One thing to remember is the backlash in the gear train and always feed in the direction of travel


----------



## DavidR8

@SLK001 newbie question; is it a 60 degree triangular file?


----------



## mikey

SLK001 said:


> The leaded steel cuts very nice (that's what the "L" in the designation means).  South Bend used a lot of leaded material for that reason.
> 
> As for the 0º vs 29.5º-30º argument, the 30º approach puts less cutting stress on the tool (it only cuts on the leading edge).  Less stress usually means a better looking thread.  Anyway, I usually clean up my threads with a couple of high speed passes with a triangular file to clean up the flanks of the thread, then a flat mill file to clean up the tops.
> 
> I have a 0-1" thread mike that is really, really useful.  I plan on getting both a 1"-2" and a 2"-3", but right now, I use wires for those.



Not being argumentative in the least but I just wanted to be sure Dave is clear on this. A 30 degree approach angle will have most of the cutting occurring on the leading edge of the tool because it is a flank infeed BUT the trailing edge rubs at this angle, which can lead to rough threads and chatter. This is why an approach angle between 25 - 29.5 degrees is most often recommended; it eliminates trailing edge contact and produces cleaner threads. It also eliminates the need for passes with a file to clean up the flanks. A file off the top is a common practice but if the threads are cut to the proper pitch diameter with a sharp tool, this is certainly optional. A sharp HSS tool with adequate relief angles to get past any helix angle issues also goes a long way towards eliminating the burrs the file is intended to deal with. 

No offense, SLK001. Just needed to clarify things so Dave understands why typical practices are what they are.


----------



## DavidR8

I did a bunch of reading last night and I have a much better understanding of why the 25-29.5 degree approach angle is used.
As I visualized it in my head, a perpendicular approach has both sides of the tool cutting simultaneously. I can imagine that the tool could chatter from side to side as it cuts.

Increasing the angle toward 29.5 degrees is going to decrease the cutting pressure on the right side side of the tool as more and more of the profile is cut by the left side of the tool until the left side of the tool is cutting all of the left side profile and the increasing depth is cutting the right side.
(I'm not explaining what I see in my head very well)


----------



## mikey

Dave, I've posted this chart multiple times on this forum but thought I would do it again because it is an extremely useful chart. It tells you what your blank OD should be to produce the class of fit you want, be it a class 1, 2 or 3A. It also gives you the pertinent pitch diameter so you know what your target range is when you use your thread mic. You won't need all of this data for every thread you make. Most of the time you can cut to fit a nut or female thread you already have, in which case the following formulas will get you close enough.

Estimated thread infeed using cross slide = 0.75/tpi; Alternative formula = Maj dia - Min dia / 2
Estimated thread infeed using compound = 0.75/tpi X 0.866 (which is the Cosine of 30 degrees)

Note that no formula is exact. It is wise to begin checking for fit or pitch diameter before you get to any calculated infeed. I typically start checking at least 0.005" before, or more for a class 3 thread. You do not want to overshoot your final depth of cut. 

It is also important to taper your infeed depths of cut. For the first pass, you can go up to about 0.010" deep but for subsequent passes you want to take lighter cuts because more of the tool will be engaged in the cut as you go deeper and cutting forces increase dramtically. For a second pass, 0.005" works, then 0.003-4" for the third pass, then 0.002-3 for the fourth pass and so on.


----------



## mikey

DavidR8 said:


> I did a bunch of reading last night and I have a much better understanding of why the 25-29.5 degree approach angle is used.
> As I visualized it in my head, a perpendicular approach has both sides of the tool cutting simultaneously. I can imagine that the tool could chatter from side to side as it cuts.
> 
> Increasing the angle toward 29.5 degrees is going to decrease the cutting pressure on the right side side of the tool as more and more of the profile is cut by the left side of the tool until the left side of the tool is cutting all of the left side profile and the increasing depth is cutting the right side.
> (I'm not explaining what I see in my head very well)



Dave, let me clarify one point. At 29.5 degrees, most of the cutting is done on the leading flank of the tool, while the trailing edge does make contact but it tends to wipe the trailing edge of the thread to produce a better finish there. I said above that 29.5 degrees eliminates contact; it does not, but it greatly reduces it and to beneficial effect.


----------



## DavidR8

mikey said:


> Dave, I've posted this chart multiple times on this forum but thought I would do it again because it is an extremely useful chart. It tells you what your blank OD should be to produce the class of fit you want, be it a class 1, 2 or 3A. It also gives you the pertinent pitch diameter so you know what your target range is when you use your thread mic. You won't need all of this data for every thread you make. Most of the time you can cut to fit a nut or female thread you already have, in which case the following formulas will get you close enough.
> 
> Estimated thread infeed using cross slide = 0.75/tpi; Alternative formula = Maj dia - Min dia / 2
> Estimated thread infeed using compound = 0.75/tpi X 0.866 (which is the Cosine of 30 degrees)
> 
> Note that no formula is exact. It is wise to begin checking for fit or pitch diameter before you get to any calculated infeed. I typically start checking at least 0.005" before, or more for a class 3 thread. You do not want to overshoot your final depth of cut.
> 
> It is also important to taper your infeed depths of cut. For the first pass, you can go up to about 0.010" deep but for subsequent passes you want to take lighter cuts because more of the tool will be engaged in the cut as you go deeper and cutting forces increase dramtically. For a second pass, 0.005" works, then 0.003-4" for the third pass, then 0.002-3 for the fourth pass and so on.


Thanks for this Mike. 
As I don't have thread wires or mic just yet I used the fit the female thread approach for the 3/8-16 thread.
So if I read this correctly for a 3/8-16 thread
 .75 /16 =.0468
.0468 X .866 = .0406 calculated thread depth. 
That just happens to be the table value for 3/8-16.
Fascinating!


----------



## devils4ever

DavidR8 said:


> I just bought a 0-1” thread mic last night!



 I've been using thread wires and they work, but are bit of a pain to use. I can't tell you how many times I've dropped them into the bottom of the lathe. You learn quickly to remove all swarf and debris when using thread wires so when you drop them, they will be easier to find!

Which thread mic did you purchase? I might be jealous and have to get one, too. I'm trying to resist lower-end tools especially measuring tools, but a Mitutoyo or Starrett will cost you big time. I'm thinking a Shars or SPI will probably work fine. Also, I would love a set of GO/NO GO gauges to make life easier, but they are not cheaper either.

I've learned a lot from mikey and use this formula of 0.750"/TPI to get the approx compound infeed amount. I will get to withing 0.005" to 0.008" though and start measuring because it's an approximation and it's easy to over cut especially on my small lathe. Experience!

mikey: Unless I'm reading it wrong, isn't your equations backwards? For 30 degree angle, I think it should be:
Estimated thread infeed using compound = 0.75/tpi
Estimated thread infeed using cross slide  = 0.75/tpi X 0.866


----------



## DavidR8

@devils4ever this is the mic I bought. 

Accusize Industrial Tools 0-1'' by 0.001'' Screw Thread Micrometer with 5 Anvil in Fitted Box, S916-C750 https://www.amazon.ca/dp/B0189RHDWS/ref=cm_sw_r_cp_api_i_hyAJEbP5EVS1Q


Sent from my iPhone using Tapatalk


----------



## SLK001

DavidR8 said:


> @SLK001 newbie question; is it a 60 degree triangular file?



Yes.  I also sometimes use a triangular stone to chase the threads.  This is NOT to change the overall size, but to take off the "fuzz" that results from slow turning.

That's the thread mike I have (it's 0.0001" resolution vs 0.001").  With it, you'll find that cutting threads is one thing, getting them correct is another.



mikey said:


> Not being argumentative in the least but I just wanted to be sure Dave is clear on this. A 30 degree approach angle will have most of the cutting occurring on the leading edge of the tool because it is a flank infeed BUT the trailing edge rubs at this angle, which can lead to rough threads and chatter. This is why an approach angle between 25 - 29.5 degrees is most often recommended; it eliminates trailing edge contact and produces cleaner threads. It also eliminates the need for passes with a file to clean up the flanks. A file off the top is a common practice but if the threads are cut to the proper pitch diameter with a sharp tool, this is certainly optional. A sharp HSS tool with adequate relief angles to get past any helix angle issues also goes a long way towards eliminating the burrs the file is intended to deal with.
> 
> No offense, SLK001. Just needed to clarify things so Dave understands why typical practices are what they are.



Yeah, I just rounded my angle to 30º.  I normally use 29.5º.  I should have been more precise.


----------



## SLK001

DavidR8 said:


> Alrighty folks,
> A bit more lathe time tonight.
> Having had my fill of CRS I tried some 10L.
> Cut off a chunk, faced it off, took .010 off the diameter.



You have a harmonic vibration somewhere in your drive chain.  Do you have an joint in your leather belt?


----------



## macardoso

DavidR8 said:


> Alrighty folks,
> A bit more lathe time tonight.
> Having had my fill of CRS I tried some 10L.
> Cut off a chunk, faced it off, took .010 off the diameter.



Great looking work!

You'll find that the extension ratio for well supported stock to be even more critical in threading because the forces are pretty high. That second example would have benefited from some live center TS support. 

You're really getting the hang of this! Congrats.

Next up is trying a metric thread. Requires you to have understanding of the change gears on your lathe and how to reverse the chuck out of the cut without undoing the half-nuts. Also in that bucket is internal threading and internal threading away from the chuck against a shoulder.


----------



## SLK001

Then your next step is to remove an unfinished thread from the setup, then put it back and re-establish the thread.  This is a very good skill to have if you thread a lot.


----------



## ErichKeane

SLK001 said:


> Then your next step is to remove an unfinished thread from the setup, then put it back and re-establish the thread.  This is a very good skill to have if you thread a lot.


My mechanism for re-establising threads is to take the part, look at the chuck, and toss the part in the trash heap, because that's where it was going to end up anyway


----------



## DavidR8

SLK001 said:


> You have a harmonic vibration somewhere in your drive chain.  Do you have an joint in your leather belt?


I don't actually, it's a continuous woven belt but I wonder about the marking also. It was turned using power feed so I wonder if something is amiss.


----------



## DavidR8

macardoso said:


> Great looking work!
> 
> You'll find that the extension ratio for well supported stock to be even more critical in threading because the forces are pretty high. That second example would have benefited from some live center TS support.
> 
> You're really getting the hang of this! Congrats.
> 
> Next up is trying a metric thread. Requires you to have understanding of the change gears on your lathe and how to reverse the chuck out of the cut without undoing the half-nuts. Also in that bucket is internal threading and internal threading away from the chuck against a shoulder.


Thanks Erich, it definitely feels like I'm getting a sense of it.
Yes in hindsight it definitely would have. The tolerance  with the nut is closer at the beginning of the thread which I suspect is because deflection allowed the end to flex away from the tool and end up slightly larger.


----------



## DavidR8

macardoso said:


> Great looking work!
> 
> You'll find that the extension ratio for well supported stock to be even more critical in threading because the forces are pretty high. That second example would have benefited from some live center TS support.
> 
> You're really getting the hang of this! Congrats.
> 
> Next up is trying a metric thread. Requires you to have understanding of the change gears on your lathe and how to reverse the chuck out of the cut without undoing the half-nuts. Also in that bucket is internal threading and internal threading away from the chuck against a shoulder.


I do want to try metric as well as internal as I want to have the full repertoire of skills.
I did forget to reset the cross slide once last night and I just reversed back to the start so I didn't have to wait for my mark on the thread dial to come back around. 

Come to think of it, if I pick a certain number on the dial do I always have to wait for the same number or can I engage on its opposite.
Say I start on the '1', can I also engage on the '3'? 
Likewise start on the '2' and also engage on the '4'?


----------



## ErichKeane

DavidR8 said:


> I do want to try metric as well as internal as I want to have the full repertoire of skills.
> I did forget to reset the cross slide once last night and I just reversed back to the start so I didn't have to wait for my mark on the thread dial to come back around.
> 
> Come to think of it, if I pick a certain number on the dial do I always have to wait for the same number or can I engage on its opposite.
> Say I start on the '1', can I also engage on the '3'?
> Likewise start on the '2' and also engage on the '4'?


That depends on your lathe and the TPI that you're cutting.  For some lathes that is true, for some 'even' threads can be on any number, odds only on opposing, etc.

Mine for example (as an oddball!) I can engage whole thread numbers on ANY number or hash, "1/2" TPIs on only the numbers, and "1/4" TPIs I have to leave it engaged !  Most lathes however don't support 1/2 and 1/4 threads (like 1 3/4 TPI!)


----------



## macardoso

DavidR8 said:


> I do want to try metric as well as internal as I want to have the full repertoire of skills.
> I did forget to reset the cross slide once last night and I just reversed back to the start so I didn't have to wait for my mark on the thread dial to come back around.
> 
> Come to think of it, if I pick a certain number on the dial do I always have to wait for the same number or can I engage on its opposite.
> Say I start on the '1', can I also engage on the '3'?
> Likewise start on the '2' and also engage on the '4'?



For reference only, my lathe has a nameplate with this chart... Yours will likely be different.




It states where on the thread dial I can engage. My thread dial has 4 major ticks (1, 2, 3, 4) and 4 minor ticks not labeled. The SCALE section above means this:

"1-8" Engage on any major or minor tick
"1-4" Engage on any major tick
"1/3 2/4" Engage on ticks 1 & 3 OR 2 & 4 (Engaging on 1 then 2 would ruin the thread)
"1" Engage on any major tick, but then only use that tick going forward
"/" Do not disengage half nuts
All metric threads and any imperial threads not in the table are assumed to be "/"


----------



## ErichKeane

DavidR8 said:


> I do want to try metric as well as internal as I want to have the full repertoire of skills.
> I did forget to reset the cross slide once last night and I just reversed back to the start so I didn't have to wait for my mark on the thread dial to come back around.
> 
> Come to think of it, if I pick a certain number on the dial do I always have to wait for the same number or can I engage on its opposite.
> Say I start on the '1', can I also engage on the '3'?
> Likewise start on the '2' and also engage on the '4'?


Assuming the 10k is the same as the grizzly one now, see Page 50: https://cdn0.grizzly.com/manuals/sb1002_m.pdf

According to that doc:
TPI divisible by 4:   Any line (numbered or not)
12/20/28/36/44/52/92: Non-numbered only.  [0]
10/14/18/22/26/46: Any numbered.
9/11/13/23: 1, 3, 5, or 7
11.5 TPI: 1/5 OR 3/7.

[0] This is confusing to me... a number of those examples ARE divisible by 4...


----------



## DavidR8

macardoso said:


> For reference only, my lathe has a nameplate with this chart... Yours will likely be different.
> 
> View attachment 320144
> 
> 
> It states where on the thread dial I can engage. My thread dial has 4 major ticks (1, 2, 3, 4) and 4 minor ticks not labeled. The SCALE section above means this:
> 
> "1-8" Engage on any major or minor tick
> "1-4" Engage on any major tick
> "1/3 2/4" Engage on ticks 1 & 3 OR 2 & 4 (Engaging on 1 then 2 would ruin the thread)
> "1" Engage on any major tick, but then only use that tick going forward
> "/" Do not disengage half nuts
> All metric threads and any imperial threads not in the table are assumed to be "/"


That's a really helpful chart. I'm pretty sure the chart on my lathe doesn't have that extra info but I'll check.
Edit: no such luck. My chart has threads per inch and feeds in thousandths.


----------



## macardoso

DavidR8 said:


> That's a really helpful chart. I'm pretty sure the chart on my lathe doesn't have that extra info but I'll check.
> Edit: no such luck. My chart has threads per inch and feeds in thousandths.


That chart is tacked on to my thread dial directly. Unfortunate yours doesn't have it. Check a manual for something similar.

At a minimum, for any normal imperial pitch, you should be able to engage/disengage on the same mark and it will be OK.

What lathe do you have?


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## DavidR8

macardoso said:


> That chart is tacked on to my thread dial directly. Unfortunate yours doesn't have it. Check a manual for something similar.
> 
> At a minimum, for any normal imperial pitch, you should be able to engage/disengage on the same mark and it will be OK.
> 
> What lathe do you have?


I have a 1975 SB 10K
I'm just in the process of making an Excel version of the threading chart so that I can read the feed rates. It's in excellent condition but brass numbers on a red background are not the great.


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## ErichKeane

Mine has the thread dial on a apron right next to the thread dial.  You might just need to consult your manual.  The Grizzly one I found above is clearly not the right one for you.  I don't see the manual to a 10K even on Vintage Machinery, which surprises me!

Hopefully someone else more familiar with the SB can chime in.


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## SLK001

Take this chart and print it, then go to a stationary store and get it laminated.  Place above your lathe.


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## mikey

devils4ever said:


> mikey: Unless I'm reading it wrong, isn't your equations backwards? For 30 degree angle, I think it should be:
> Estimated thread infeed using compound = 0.75/tpi
> Estimated thread infeed using cross slide  = 0.75/tpi X 0.866



No, don't think so.

Besides, I do it like you - I don't rely on calculations. I start checking early, and the more critical it is for that thread to be right, the earlier I start to check. You know how that flat at the peak of the thread starts to narrow? I tend to watch that and when it starts to look like I'm close, I pull the thread mic out and start measuring. I cannot tell you how many threads I've overshot using formulas!!


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## devils4ever

After reviewing this again, you are correct.  The compound needs to move more since it's at an angle.


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## savarin

going back to the fistail gauge I want one of these




Anything must be easier than that standard version.


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## DavidR8

Made this chart today. My eyes are pathetic.


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## SLK001

DavidR8 said:


> Made this chart today. My eyes are pathetic.



That compares to this one I did for my lathe.  It's not that my eyes are pathetic, it's just easier to see than bending down, wiping off the chart and selecting the feed I want.


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## Nigel123

mikey said:


> No, don't think so.
> 
> Besides, I do it like you - I don't rely on calculations. I start checking early, and the more critical it is for that thread to be right, the earlier I start to check. You know how that flat at the peak of the thread starts to narrow? I tend to watch that and when it starts to look like I'm close, I pull the thread mic out and start measuring. I cannot tell you how many threads I've overshot using formulas!!





mikey said:


> No, don't think so.
> 
> Besides, I do it like you - I don't rely on calculations. I start checking early, and the more critical it is for that thread to be right, the earlier I start to check. You know how that flat at the peak of the thread starts to narrow? I tend to watch that and when it starts to look like I'm close, I pull the thread mic out and start measuring. I cannot tell you how many threads I've overshot using formulas!!


I can see why you over shot your threading the formula is 0.75 divided by the TPI with the compound
If the tool is accurate and set up properly it works


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## mikey

You know what, you  and @devils4ever are correct. If feeding with the cross slide, the formula is 0.75/tpi x cosine of whatever you set the compound angle at. If feeding with the cross slide compound, which is the actual depth of thread, then the formula is 0.75/tpi.

I don't know how I got this wrong in my head because I've been doing this for a long time. I am embarrassed but I'm owning up to it right now.


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## Bamban

mikey said:


> No, don't think so.
> 
> Besides, I do it like you - I don't rely on calculations. I start checking early, and the more critical it is for that thread to be right, the earlier I start to check. You know how that flat at the peak of the thread starts to narrow? I tend to watch that and when it starts to look like I'm close, I pull the thread mic out and start measuring. I cannot tell you how many threads I've overshot using formulas!!



Mikey,

If you ask any top benchrest gunsmith in the country they will tell you to err on the loose side to allow the barrel tenon and action  shoulders to mate squarely. 

Nez


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## DavidR8

mikey said:


> If feeding with the cross slide, the formula is 0.75/tpi x cosine of whatever you set the compound angle at.
> 
> If feeding with the cross slide, which is the actual depth of thread, then the formula is 0.75/tpi.



Wait, which formula is for cross slide feeding and which is for compound feeding?


Sent from my iPhone using Tapatalk


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## Nigel123

DavidR8 said:


> Wait, which formula is for cross slide feeding and which is for compound feeding?
> 
> 
> Sent from my iPhone using Tapatalk


I use 0.742 divided by the TPI for the compound feed for 29.5 degrees
Use 0.75 divided by the TPI for the compound feed for 30 degrees
Check early say .008 before final cut in case your set up is off a little
Never threaded with cross feed only maybe someone else can enlighten us
Would like to try a thread mike or wires but might be out of my price range
Followed your thread on the mike 100 bucks but only good for up to 1 inch
Wires might be cheaper if they work accurately up to 4 inches
Have set of 1 to 6 inch mikes


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## SLK001

A set of wires is usually less than $20US.


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## Nigel123

SLK001 said:


> A set of wires is usually less than $20US.


That would be about 30 bucks up here and would need metric too
Seems affordable will give them a try
Might have to brush up on my math
Thanks for the post


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## ErichKeane

Nigel123 said:


> That would be about 30 bucks up here and would need metric too
> Seems affordable will give them a try
> Might have to brush up on my math
> Thanks for the post


I don't think you would need metric, just the chart that works.  The idea with thread wires is that they are a cylinder of a known diameter that touches both sides of the thread at a known depth (due to the diameter).  1 set of wires should work for all threads.

The wire needs to be small enough that it touches the side of the thread, and large enough that it can be measured over the crests, right?


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## Nigel123

ErichKeane said:


> I don't think you would need metric, just the chart that works.  The idea with thread wires is that they are a cylinder of a known diameter that touches both sides of the thread at a known depth (due to the diameter).  1 set of wires should work for all threads.
> 
> The wire needs to be small enough that it touches the side of the thread, and large enough that it can be measured over the crests, right?


Thanks you cut my purchase in half
Any idea where I can get a chart?
A bonus too all my mikes are imperial


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## ErichKeane

Nigel123 said:


> Thanks you cut my purchase in half
> Any idea where I can get a chart?
> A bonus too all my mikes are imperial


This set of 48 wires (all imperial) comes with a laminated copy of the chart for $23!  They also have it about 1/2 way down the ad in picture format: https://www.amazon.com/AccusizeTools-Metric-Thread-Measuring-EG06-1001/dp/B01AUZNSH6  All dimensions are in inches which makes it that much easier


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## Nigel123

ErichKeane said:


> This set of 48 wires (all imperial) comes with a laminated copy of the chart for $23!  They also have it about 1/2 way down the ad in picture format: https://www.amazon.com/AccusizeTools-Metric-Thread-Measuring-EG06-1001/dp/B01AUZNSH6  All dimensions are in inches which makes it that much easier


I just ordered that set(Great minds think alike)
Over all good reviews except the case
Thanks again for the info


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## SLK001

Nigel123 said:


> That would be about 30 bucks up here and would need metric too
> Seems affordable will give them a try
> Might have to brush up on my math
> Thanks for the post



The wires are standard agnostic.


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## mikey

DavidR8 said:


> Wait, which formula is for cross slide feeding and which is for compound feeding?
> 
> 
> Sent from my iPhone using Tapatalk



Dave, use 0.75/tpi when feeding with the compound. For feeding with the cross slide, use 0.75/tpi X 0.866. The 0.866 is the cosine of 30 degrees, which is close enough. I got it turned around because I'm remembering all this threading  stuff off the top of my head.


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## devils4ever

mikey said:


> Dave, use 0.75/tpi when feeding with the compound. For feeding with the cross slide, use 0.75/tpi X 0.866. The 0.866 is the cosine of 30 degrees, which is close enough. I got it turned around because I'm remembering all this threading  stuff off the top of my head.



Awesome! I was vindicated!!! 

Of course, I learned a LOT from you! Thanks!


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## devils4ever

mikey said:


> I think the Accusize and Shars mics are identical; so is the price. They should work just fine.



I ordered the Shars thread mic. It was a little quicker in shipping and a tad cheaper.


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## mikey

Nobody's perfect and I'm old enough to know that I'm not perfect or always right. Thing to do when you mess up is own it.


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## mikey

devils4ever said:


> Awesome! I was vindicated!!!
> 
> Of course, I learned a LOT from you! Thanks!



Let's hope the rest of it is right!   

Unbeknownst to you guys, I learn a lot from you, too. You guys keep me on my toes, and you do it so gently, too, which I appreciate. When I or anyone else is laying down wrong information, call it out because there is some silent new guy out there absorbing this stuff like a sponge.


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## mikey

Just wanted to offer an opinion on mics vs wires. Both work, both are accurate but one is a major PIA to use and one is simple and easy to use. One requires calculations and searching in the chip pan and the other is direct reading. When you are bent over the work trying to mic over wires for the fifth or sixth time as you get close to your pitch diameter, then search again for the wires you dropped, then calculate for the fifth or sixth time, the minor cost savings of cheap thread wires will disappear in a cloud of irritation. 

It is your call, of course, but if I were you I would go and buy a thread mic. They are dirt cheap nowadays ... and they will save what hair you have left.


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## ErichKeane

mikey said:


> Just wanted to offer an opinion on mics vs wires. Both work, both are accurate but one is a major PIA to use and one is simple and easy to use. One requires calculations and searching in the chip pan and the other is direct reading. When you are bent over the work trying to mic over wires for the fifth or sixth time as you get close to your pitch diameter, then search again for the wires you dropped, then calculate for the fifth or sixth time, the minor cost savings of cheap thread wires will disappear in a cloud of irritation.
> 
> It is your call, of course, but if I were you I would go and buy a thread mic. They are dirt cheap nowadays ... and they will save what hair you have left.


For what its worth, I have a cheap set of thread wires, and a 0-1 mic which I think is the perfect combo.  I rarely cut >1" threads, so the cheap set of wires covers for those cases.  The other 99% of my threading is covered by the mics.


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## Nigel123

mikey said:


> Just wanted to offer an opinion on mics vs wires. Both work, both are accurate but one is a major PIA to use and one is simple and easy to use. One requires calculations and searching in the chip pan and the other is direct reading. When you are bent over the work trying to mic over wires for the fifth or sixth time as you get close to your pitch diameter, then search again for the wires you dropped, then calculate for the fifth or sixth time, the minor cost savings of cheap thread wires will disappear in a cloud of irritation.
> 
> It is your call, of course, but if I were you I would go and buy a thread mic. They are dirt cheap nowadays ... and they will save what hair you have left.


Good advice most of my threading is under 1 inch
The 1 inch accusize is 98.00 dollars
I see the shars is on sale for 55.00 u.s.
Will look into shipping costs for the shars if they ship to Canada
I can always use the wires for larger diameters
Maybe a dumb question how do you get your name on the like reply
mine shows up as you or 1 other person


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## mikey

Nigel123 said:


> Maybe a dumb question how do you get your name on the like reply
> mine shows up as you or 1 other person



Not sure what you mean. When you hit the reply hyperlink at the bottom of the post you're replying to, the person who wrote that post is notified that you replied. Same if you liked that post. What am I missing?


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## Nigel123

mikey said:


> Not sure what you mean. When you hit the reply hyperlink at the bottom of the post you're replying to, the person who wrote that post is notified that you replied. Same if you liked that post. What am I missing?


The thumbs up icon showing names like mikey or davidR8 when i give the thumbs up 
it just shows you


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## DavidR8

I see your thumbs up @Nigel123


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## Nigel123

DavidR8 said:


> I see your thumbs up @Nigel123
> View attachment 320342


I said it was a dumb question It must change when read on other members computers
Can I take a senior moment for this one?


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## savarin

It says you on your screen but everyone else sees your name


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## devils4ever

mikey said:


> Just wanted to offer an opinion on mics vs wires. Both work, both are accurate but one is a major PIA to use and one is simple and easy to use. One requires calculations and searching in the chip pan and the other is direct reading. When you are bent over the work trying to mic over wires for the fifth or sixth time as you get close to your pitch diameter, then search again for the wires you dropped, then calculate for the fifth or sixth time, the minor cost savings of cheap thread wires will disappear in a cloud of irritation.
> 
> It is your call, of course, but if I were you I would go and buy a thread mic. They are dirt cheap nowadays ... and they will save what hair you have left.



I agree totally that the wires are a big PITA. The are cheap and they do work and I'll keep them for when I need to go bigger than 1" diameter or if I ever decide to cut Acme threads.

For anyone using wires, these are the charts that came with my Brown & Sharp Thread Pitch Diameter Wire Set. As you can see, it will do both Imperial and Metric as well as Acme threads.


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## ErichKeane

devils4ever said:


> I agree totally that the wires are a big PITA. The are cheap and they do work and I'll keep them for when I need to go bigger than 1" diameter or if I ever decide to cut Acme threads.
> 
> For anyone using wires, these are the charts that came with my Browne & Sharpe Thread Pitch Diameter Wire Set. As you can see, it will do both Imperial and Metric as well as Acme threads.
> 
> View attachment 320420
> 
> 
> View attachment 320421


First, the acme chart is awsome!  I'll have to see if my B&S set came with any cards!  Second, I was really wondering what the 'add' column in the chart meant!  Its nice that this one says it!


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## raven7usa

Here's an easy way to use thread wires.


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## ErichKeane

raven7usa said:


> Here's an easy way to use thread wires.


I don't remember which youtuber mentioned it at one point (maybe buildsomethingcool?), but you have to be careful doing that.  If the wires 'flex in any way as a result of that, it'll make your measurement look larger and result in the measurement being larger than it is, and likely resulting in an overcut.


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## higgite

I don't use thread wires, so can't comment on its effectiveness, but I recently saw a youtuber use a small dab of grease to hold the wires in place while he positioned them and fidgeted with his micrometer. It seemed to work well for him.

Tom


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## SLK001

I've heard of people using the styrofoam shipping peanuts to hold the wires (stick them into the peanut).


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## macardoso

I do nearly all my measuring with wires. With some practice I certainly don't find them as difficult to use as most people claim. Certainly not as easy as a mic, but I never have issues with it. It also allows me to use my normal mic, calibrated against standards. You can't do that with a thread mic unless you have a thread master (which I don't).

But from a convenience factor, thread mics are great.

I worked for a while in a metrology lab and the gold standard is thread Go-NoGo gages. Very expensive to buy them for all your thread sizes and all tolerance classes. We probably had 15 sets of rings for each size of thread for various tolerance classes (ASME, DIN, ISO, etc). When I do production jobs, I will invest in the gages required for the job if the quantity is over a couple dozen. Very reliable to check that way.


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## tmenyc

I also have found them less annoying with practice; basically tell myself I'm not digging through the chips even one more time, so get it right!
Tim


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## devils4ever

I cut a 3/8"-16 thread on my lathe and had a chance to use my new Shars thread mic. According to the Theoretical Machinist.com's thread calculator, the pitch diameter range for this thread is: 0.3287" to 0.3331". I measured 0.3312" with my Shars thread mic. It fit the matching thread perfectly! I must say the thread mic is definitely easier to use than the wires, but it still requires a little finesse in using.

Also, I confirmed that the 0.75/TPI equation works. In this case, 0.75/16 = 0.0469". I advanced my compound by 0.044". Like previously mentioned, use this equation as a guideline and keep measuring as you get close!


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## SLK001

Good looking threads.  The biggest problem I have with the Shars TM is setting the zero when you change the anvils.  You have to ensure than when you ratchet the TM to zero, it actually reads zero - if not, you have to adjust the bottom anvil and retest.


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## devils4ever

SLK001 said:


> Good looking threads.  The biggest problem I have with the Shars TM is setting the zero when you change the anvils.  You have to ensure than when you ratchet the TM to zero, it actually reads zero - if not, you have to adjust the bottom anvil and retest.



Thanks!

Yes, that's true.

Isn't that true of all thread mics that have changeable anvils? I know Starrett makes thread mics with fixed anvils which require you to buy a full set for all the thread pitches. Each one is over $350.


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## macardoso

devils4ever said:


> Thanks!
> 
> Yes, that's true.
> 
> Isn't that true of all thread mics that have changeable anvils? I know Starrett makes thread mics with fixed anvils which require you to buy a full set for all the thread pitches. Each one is over $350.



That's what we would use in the inspection lab at work. Saves money in the long run if your inspection guys aren't wasting a ton of time re-zeroing the equipment between every part. That and a ton of thread gauges. We also had Starrett make us some custom micrometers for doing precision gears.


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## devils4ever

macardoso said:


> That's what we would use in the inspection lab at work. Saves money in the long run if your inspection guys aren't wasting a ton of time re-zeroing the equipment between every part.



That makes sense in a production environment.


----------



## Nigel123

devils4ever said:


> I cut a 3/8"-16 thread on my lathe and had a chance to use my new Shars thread mic. According to the Theoretical Machinist.com's thread calculator, the pitch diameter range for this thread is: 0.3287" to 0.3331". I measured 0.3312" with my Shars thread mic. It fit the matching thread perfectly! I must say the thread mic is definitely easier to use than the wires, but it still requires a little finesse in using.
> 
> Also, I confirmed that the 0.75/TPI equation works. In this case, 0.75/16 = 0.0469". I advanced my compound by 0.044". Like previously mentioned, use this equation as a guideline and keep measuring as you get close!
> 
> View attachment 321158


Nice looking threads
Still waiting for the thread mic to arrive
The formula is pretty handy to use if set up is right but only good if the parts can be fitted 
Funny you cut a 3/8 16 thread the last one I cut about 3 months ago
First pass looked O.K.
Second pass a little rough
Third pass took the points off the thread
Note to self change lathe back to imperial after threading metric


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## devils4ever

I found I have to take very light cuts when threading on my mini lathe. The first few passes I can do 2-3 thousandths. After that, I  only do 1 thousandth cuts. I sometimes repeat the cut at the same depth to make sure it's clean and not stressing anything. I'm sure a full size lathe can do much deeper.


----------



## Nigel123

devils4ever said:


> I found I have to take very light cuts when threading on my mini lathe. The first few passes I can do 2-3 thousandths. After that, I  only do 1 thousandth cuts. I sometimes repeat the cut at the same depth to make sure it's clean and not stressing anything. I'm sure a full size lathe can do much deeper.


If the work is well supported I start at about 8 to 10 thousandths then drop to 5 or so one or two spring passes to clean it up
1 or 2 at the finish to get the fit
Looking forward to try the mic when it comes hope to be able to machine a thread and have 
a good fit without test fitting


----------



## devils4ever

You must have bigger lathe than me. If I go too deep, I get into _trouble _quick!


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## Nigel123

devils4ever said:


> You must have bigger lathe than me. If I go too deep, I get into _trouble _quick!


12 x 37 with 2 hp motor I use HSS tooling with no rake
Trying carbide threading inserts have to change my methods 
seem to be cumbersome especially when using the tail stock
and cutting smaller dia threads


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## SLK001

devils4ever said:


> You must have bigger lathe than me. If I go too deep, I get into _trouble _quick!



There is something really wrong if all you can cut is 0.001" each pass.  What lathe do you have?  Are you using the cross slide, or the compound to feed the cutter?


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## ErichKeane

SLK001 said:


> There is something really wrong if all you can cut is 0.001" each pass.  What lathe do you have?  Are you using the cross slide, or the compound to feed the cutter?


Yeah, that doesn't sound right.  I'd make sure the tool is on-center (even more important on a hobby lathe!) and sharp, and your belt tensioned.  On the smaller lathes you might find that upping the RPM helps a little as well.


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## devils4ever

I have the MicroLux 7X16 mini-lathe from MicroMark. I'm using the compound set to 30 degrees.

I run the lathe at very low speeds to stop the cut in time. Probably in the 30-40 RPM range.

If I take deeper cuts, I'll get chatter and/or the tool with jam into the work piece and jam up everything.


----------



## Nigel123

devils4ever said:


> I have the MicroLux 7X16 mini-lathe from MicroMark. I'm using the compound set to 30 degrees.
> 
> I run the lathe at very low speeds to stop the cut in time. Probably in the 30-40 RPM range.
> 
> If I take deeper cuts, I'll get chatter and/or the tool with jam into the work piece and jam up everything.


If the gibs are tight and setup is right try 29 degrees it might make a difference
cutting on the leading edge only
I also own a 109 craftsman lathe bought in 1970
Did some threading on it definately had to go slower
All said those are nice threads you did


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## SLK001

Try adding a center to the tailstock to support the end of your work.


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## devils4ever

SLK001 said:


> Try adding a center to the tailstock to support the end of your work.



Yep, already do that. I just moved it out of the way for the photo.


----------

