# Single Point Threading = no Depth Gauge Joe P.



## Janderso (Apr 4, 2020)

One of my favorite YouTube channels is Joe Pieczynski.
He is a great teacher imho.
As a hobby machinist with little practical experience, I am always learning. 
Therefore, I watched this video, “Single Point Threading, Want to do it better?” By Joe Pi.
In this video, Joe says, “If someone walks into my shop and asks, how deep should I cut this thread, throw him out”.
”Threads are not driven by the depth of the thread”.
I guess if you own a thread mic., put it away?
He explained to me the method to use is the 3-wire and follow the machinists handbook and the instructions that come with the thread wire kit.
This experience has given me confidence moving forward with respect to single point threading and learning more about threads.
Did you know the 2A is for external or “air” threads? did you know the 2B threads are for the “bore” or internal?
I do now.
The pics show my latest project, a smaller machinists jack. I cut the threads 5/8 x 18 UNF. I’m I followed the 2A specs. I put it in the imaginary mail and received the external thread portion to fit into my internal machinist jack base that I cut using a commercial tap.
It fits perfectly with no slop and smooth as glass. Did I get lucky or is this why there are published standards.


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## ttabbal (Apr 4, 2020)

As I understand it, and I'm a noob too, thread mics measure the same thing wires + mic do, the thread pitch diameter. So they should be equivalent when it comes to accuracy.

The how deep to cut is when people want to go to a certain depth of cut on the dials or DRO. It's a close approximation a lot of the time, but can lead to parts that don't thread to standard fasteners.

Nice job on the jack. I'd like to make some myself sometime.


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## jaek (Apr 4, 2020)

Looks pretty good!

FWIW a thread mic measures the pitch diameter (quality of fit) directly, just like the three-wire method. No need to throw it away.

Thread depth depends on major and minor diameters which aren't as critical. It's the reason "75% thread for aluminum, 50% thread for steel" thing works.


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## mikey (Apr 4, 2020)

You did a nice job on your jack!

Have to agree that Joe Pi is a great teacher, and I really like his personality - confident, capable and direct. 

Thread wires are actually very accurate and capable of being more accurate than most thread mics that read in the thousandths. More accurate because you can read wires to the tenths with a tenths reading mic. However, wires are a serious pain in the butt and I hate them so I don't use them. A thread mic is far more convenient to use, is direct reading and is more than accurate enough to obtain excellent thread fits.

There is a LOT to know about threads, thread fits and cutting threads. Took me a long time to understand it but then again, I'm slow. You might look into the fit classes and learn how to cut what you need, on purpose and to specs. Cutting a class 3A and matching class 3B thread is not as easy as it looks because you are cutting and measuring to tenths. On smaller threads, like a class 3 10-32 thread, the OD of your blank and the thread pitches are within a few tenths and you have to be able to work at that level of accuracy. Looks easy on paper, not so easy at the lathe. 

Take your time and maybe look into grinding a good HSS threading tool. It will make your life so much easier and your thread form will be much cleaner.


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## Janderso (Apr 4, 2020)

The one thing that still has me baffled, how do you assure you are cutting accurate internal threads? Is a bore gauge the only way?
I work alone, I don't ship my parts off to a job offsite. I make fit and finish adjustments on the fly so it's easy for me to start checking fit when I'm getting close to depth.


jaek said:


> Looks pretty good!
> 
> FWIW a thread mic measures the pitch diameter (quality of fit) directly, just like the three-wire method. No need to throw it away.
> 
> Thread depth depends on major and minor diameters which aren't as critical. It's the reason "75% thread for aluminum, 50% thread for steel" thing works.


Now that you mention it, you are correct. I had forgotten you need to change the adapters for different thread pitches on thread micrometers. I don't own one so I am unfamiliar with them.


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## benmychree (Apr 4, 2020)

For nearly all my threading, I use the threading tools from Aloris, they are made in several sizes according to the width of flat at the point of the tool, they are sharpened only on the top, and last a very long time.  Yes, thread wires are a PITA, and I seldom use them, and then, only if my thread mikes are too small, then I go to my old shop and borrow the larger one.  I think one can read a .001 thread mike to within a few tenths by approximation, I have never had to make anything closer than that.   At my old shop I had a collection of thread ring gages, and used them to fit most threads.


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## benmychree (Apr 4, 2020)

Janderso said:


> The one thing that still has me baffled, how do you assure you are cutting accurate internal threads? Is a bore gauge the only way?
> I work alone, I don't ship my parts off to a job offsite. I make fit and finish adjustments on the fly so it's easy for me to start checking fit when I'm getting close to depth.
> 
> Now that you mention it, you are correct. I had forgotten you need to change the adapters for different thread pitches on thread micrometers. I don't own one so I am unfamiliar with them.


Most of the thread mikes that I have seen do not have interchangable anvils, they only work for a range of pitched, in 0-1 there are three mikes for the whole range of threads.  For gageing internal threads, a thread plug gage is used, you just screw it in and feel for the fit; like the external gages, they come in GO and NO GO styles, varying in pitch diameter, one should screw in or on and the other should not.
I have made my own plug gages for such as my lathes with screw on chucks, so that when I need to make a backplate for a chuck or whatever, I use it to fit the internal thread.  It is made to the exact pitch diameter as the lathe spindle, using a thread mike.  Having said that most of the thread mike that I have seen do not have interchangable anvils, when I had my shop downtown, I bought three of them (up to 3 inch) made in Poland, and used them a good bit; I can still borrow them if need be.


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## mikey (Apr 4, 2020)

Janderso said:


> The one thing that still has me baffled, how do you assure you are cutting accurate internal threads? Is a bore gauge the only way?
> I work alone, I don't ship my parts off to a job offsite. I make fit and finish adjustments on the fly so it's easy for me to start checking fit when I'm getting close to depth.



The vast majority of threads we make in a hobby shop will be class 2 threads. We can cut the external thread and then cut the internal thread so that it fits the external one we made. This is how most of your threads will be made. If you need a class 3b thread then the best way is to make (or buy) a go/no-go gauge. You will not do this often but if you have to have it, this is how you do it in a hobby shop.


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## brino (Apr 4, 2020)

Jeff I always enjoy Joe Pi's videos.....and your posts......



Janderso said:


> It fits perfectly with no slop and smooth as glass. Did I get lucky or is this why there are published standards.



I believe it's simply that you are paying attention, learning, and getting great at it!
I need more shop time......

-brino


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## mikey (Apr 4, 2020)

Most all modern thread mics now have interchangeable anvils. Gone are the days of the beautiful Starrett and Lufkin fixed standard thread mics. My Tesa set, Mitutoyo, B&S and even the cheap Chinese ones all have interchangeable anvils. Aesthetically, I don't think the more modern tools are better but changing anvils is a lot cheaper than having separate mics.


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## Janderso (Apr 4, 2020)

mikey said:


> Most all modern thread mics now have interchangeable anvils. Gone are the days of the beautiful Starrett and Lufkin fixed standard thread mics. My Tesa set, Mitutoyo, B&S and even the cheap Chinese ones all have interchangeable anvils. Aesthetically, I don't think the more modern tools are better but changing anvils is a lot cheaper than having separate mics.


I toyed with the idea of buying a quality used thread mic on E-bay, when I saw the small range of threads they measure I decided I don’t need a set that bad.
I like the idea of buying one with interchangeable tips.


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## mikey (Apr 4, 2020)

Janderso said:


> I toyed with the idea of buying a quality used thread mic on E-bay, when I saw the small range of threads they measure I decided I don’t need a set that bad.
> I like the idea of buying one with interchangeable tips.



Shars sells a set for under a hundred bucks for a 0-1 thread mic. Reads in tenths, too. Most higher end mics will read in thousandths, although you can interpolate easily enough for greater accuracy, as John said.


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## ttabbal (Apr 4, 2020)

I have the Shars 0-1 thread mic. I think it works quite well. Like all precision tools it takes some practice to get good repeatable measurements. I grabbed some known good fasteners from McMaster and fastenal and measured them, comparing to a chart to make sure I'm in the right range. Once I got comfortable, I used it for cutting and got a great fit. 

I tried with home store bolts, but I got weird results. Turns out I was doing it right and they are barely in spec and some were slightly out. Explained why some of them didn't fit the nuts well. It was confusing at first though.


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## Alexander McGilton (Apr 4, 2020)

I wish some one would tell this to Heidenhain. This is a clipping from the heidenhain 4110 manual. It request that you specify the thread depth by radius dimension U of major diameter to root. I would wish that they made the system work by thread pitch diameter and the theoretical convergence of the tool. Though that would make things more complicated for the user. What I do is set the U to 0.5*F1, take a test cut then compensate linearly after checking with the thread micrometer.


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## Janderso (Apr 5, 2020)

benmychree said:


> For nearly all my threading, I use the threading tools from Aloris, they are made in several sizes according to the width of flat at the point of the tool, they are sharpened only on the top, and last a very long time.  Yes, thread wires are a PITA, and I seldom use them, and then, only if my thread mikes are too small, then I go to my old shop and borrow the larger one.  I think one can read a .001 thread mike to within a few tenths by approximation, I have never had to make anything closer than that.   At my old shop I had a collection of thread ring gages, and used them to fit most threads.


You talking about this style John?


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## Janderso (Apr 5, 2020)

More threading fun today.
I’m gaining confidence. This is a 5/16 18 thread.  No I didn’t use a die, what’s the fun in that


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## MrWhoopee (Apr 5, 2020)

Janderso said:


> More threading fun today.
> I’m gaining confidence. This is a 5/16 18 thread.  No I didn’t use a die, what’s the fun in that



As Fred would say:
"You do nice work........
  damn little of it, but nice work" 


But seriously, nice looking part. You're definitely getting the hang of this.


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## projectnut (Apr 5, 2020)

Janderso said:


> You talking about this style John?
> 
> 
> 
> ...



I have a couple threading tools like that.  One is for the BXA tool holder and the other is for the AXA  tool holder.  They're nice if I have to do long threading or multiple pieces.  However I find myself using a plain old HSS tool ground to a 60* angle more often than not.  

Like benmychree I've made several plug gauges  for testing internal threads.  The first one I made was for a 1 7/16-12 backing plate on my Seneca Falls Star lathe.  It turned out perfect and I was extremely proud of it until I tried to use it.  No matter what I did I couldn't get it to fit my practice piece.  I was frustrated beyond belief and finally put a thread gauge on it.  In error I had put the wrong change gear on the lathe.  Instead of cutting a 1 7/16-12 thread I was cutting a 1 7/16-11 1/2 thread.  Since I've never owned or worked on anything with a 1 7/16-11 1/2 thread I've never had the occasion to use the plug.  I do however keep in a prominent place where I can see it while using that lathe.  It's a constant reminder to check twice and only have to cut once.


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## Bamban (Apr 6, 2020)

Projectnut,

Are you telling me a 1-1/16x16 barrel tenon will not screw all the way into an action  with 1-1/16x18 thread? 

Well, I tried desperately, and in fact I cut off the tenon and cut new one, still the same results. 

My brother has a glued in bench gun, I volunteered to make him a fire forming barrel from a shot out barrel. The action being glued, can't test fit till done since I was chambering through the headstock. 

I downloaded the tenon print from the action manufacturer, used it to cut the barrel, somehow I proved I could not read, my mind was focused on the 1 1/16, and at that time I was doing a lot of AR15 barrels with 16 TPI tenon. Automatically, I set the gearbox to cut 16. 

Not till I failed on the 2nd attempt did I read the print again, and there it was - 18 TPI.


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## Janderso (Apr 6, 2020)

Bamban,
I had to read your post twice to find the error. Oops.
Hey, you knew enough to figure it out.


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## brino (Apr 6, 2020)

Bamban said:


> Not till I failed on the 2nd attempt did I read the print again, and there it was - 18 TPI.



Mis-read is one of my problems, but also some 8's really look like 6's........and vise-versa.
It's like my eyes are getting older every day!
-brino


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## projectnut (Apr 6, 2020)

Bamban said:


> Projectnut,
> 
> Are you telling me a 1-1/16x16 barrel tenon will not screw all the way into a action  with 1-1/16x18 thread?
> 
> ...



Welcome to the Slow Learners Club.  This is a fairly exclusive community.  Not many qualify, and those that do often live in a world of their own.  Most of us are ahead of the times.  Because of the way we think and the things we do people have been social distancing themselves from us for years.  Who knew it would come in handy some day.


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## Janderso (Apr 6, 2020)

Projectnut,
Are you saying us hobby machinists are loners? 
Well, I for one am to a tee. There is nothing I would rather do than spend a week in my shop.
The perfect vacation!


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## DavidR8 (Apr 6, 2020)

Janderso said:


> Projectnut,
> Are you saying us hobby machinists are loners?
> Well, I for one am to a tee. There is nothing I would rather do than spend a week in my shop.
> The perfect vacation!


Introverts unite!


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## projectnut (Apr 6, 2020)

I wouldn't necessarily classify all hobby machinists as loners or introverts.  I for one spent 20+ years dealing with customers in the auto repair business and another 20+ years dealing with people in the machine design, fabrication, and production environment.  I did (in most cases) like the people, and thoroughly enjoyed the work.

The work was demanding and more often than not required 60 to 80 hour work weeks.  Add into that traveling for 200+ days a year and it was just about all consuming.  Time with the family and in the shop was all but non existent.  Fortunately it was rewarding, and the wife didn't have a problem with it.  Now that I'm officially retired it's time to do the family things and hobby things I missed out on during my working career.  Don't get me wrong I've enjoyed every minute of it, and wouldn't change a thing.  It's just time to change course and slow down a bit.


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## Janderso (Apr 6, 2020)

Of course we are all different with splendid personalities.
Life would be so boring and predictable if we were all the same.
I have noticed over my 63 years that some people that are mechanically inclined are a bit awkward in a social setting. (I'm including in this category.)
On the other hand, I've worked around sales guys also, I have found most sales oriented people do not know how to work a screw driver.
I'm not trying throw any stones or anything, this is just my personal observation.


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## LEEQ (Apr 7, 2020)

Jeff, I'm late to the party. That said, before you go buying fancy mics and gauges watch all of Joe's threading videos. Think abt subscribing, he's got tons of great stuff. The threading series covers measuring over 1, 2, or three wires as well as what specs to cut your own plug gauges. He'll have you cutting your relief groove with your threading tool so you can use 1 or 2 wires to measure and cut it to finished pitch diameter. Then you'll set your dial to 0 and cut threads to 0 with confidence to full depth of thread as proven by using your wires to measure pitch diameter. P.D. wires are cheap and come with instructions, and Machinery Handbook will show you how to find your over the wire numbers. It's satisfying to look it up and cut it to proper standards and know it will fit storebought hardware. Another super handy gadget is the machinist calculator from Calculated Industries. It will spit out all the threading info once you give it the class (A or B) and size. It will tell you what wires to use, your pd #'s, pd#'s with the wires you have if you don't have the perfect wire, major and minor diameters, tap drills, clearance drills, everything you need and then some. It's like having the information I get from 3 or 4 places in the Handbook on a few buttons . Mine is the app not the physical calculator, a great way to try it on the cheap.  It has speed and feed calculating functions, as well as Trig functions in addition to threads. It is the prince of shop calculators in my humble opinion. I rely on their carpentry one to help me make a living, it's all aces too. Enjoy your Joe Pi and your thread cutting.


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## hman (Apr 11, 2020)

DavidR8 said:


> Introverts unite!


No, we don't!  That's what makes us introverts. (sorta like the Procrastinator's Club - we're all members, just haven't gotten around to submitting the paperwork).  

But on a more serious note, I've found that "social distancing" has not made that great a change in my life. I do have a lot of sympathy for those who are extroverts.  This is probably hitting them pretty hard.  Social media, etc. will only take you so far.  It's a poor substitute for close, personal contact.  Be well, everybody ... and ENDURE.


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## ttabbal (Apr 11, 2020)

Yeah.. Hasn't bothered me much. My sister sent me a meme showing a programmer normally working, and one on quarantine. Same picture for both..  

Work, cut some metal, maybe make a few radio contacts... Sleep, repeat.


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## ACHiPo (Apr 11, 2020)

Janderso said:


> You talking about this style John?
> 
> 
> 
> ...


That’s the kind I have.  It’s too tall to be on center so I need to mill a bit off the bottom of the holder.


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## Tim9 (Apr 11, 2020)

I thought about buying a mic....but being Chinese and different anvils...I passed. Especially after seeing Joe P’s video. I’ll stick with wires. 
  Mr Pete has a trick where he uses a piece of delrin plastic to hold the wires. It’s almost impossible to hold the damned wires and a mic with just 2 hands. Using a cork or piece of plastic really makes it a breeze. And in all honesty....as critical as threads can be....I just wouldn’t trust a Cheap Asian import mic with A bunch of interchangeable anvils. Seems like a recipe for a screw up.


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## mikey (Apr 11, 2020)

Tim, can't disagree with you but those Chinese mics might be better than you think. I was using a borrowed Fowler thread mic with changeable anvils for maybe 10 years or so. Yeah, over 10 years, good friend! Anyway, I finally got my mitts on a Tesa 0-1" and 1-2" thread mic set. They were in mint condition and read dead on with the Tesa standard. Before I sent that Fowler back to my friend, I checked it against my Tesa mics and it read dead on the same and the readings were consistent from bolt to bolt.

The Fowler set looks exactly like the one sold by Shars and others. Not saying they are going to be as accurate but I bet they will be. I used thread wires for over 10 years and I can tell you that they are more technique-dependent that many realize. If your mic anvils are off center, or there is debris, burrs or oil under those wires the readings will be off. And I am not guessing at this. Thread mics are much more forgiving of error in addition to being direct reading, fast and accurate.

Your call. The choice to go with thread wires or a mic is a personal choice but I will never go back to wires except for Acme or BSW threads or if I have a work piece larger than 2".


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## Tim9 (Apr 11, 2020)

Good to know Mike. I was ready to buy a Shars anvil type mike since I’ve always had good luck with Shars. But it had a bad review. Maybe it was a troll. Anyway...God I’ve got lots of tools. And I really need to slow down. Already have wires and Joe P is a sharp guy. Since I really have done most of my threads by feel....it’s not really something I use much to begin with. Last thing I did use wires and it was a dead nuts nice thread....so I’ll probably just stick with what I got.


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## Dabbler (Apr 11, 2020)

The Canadian military will not accept using thread wires to measure and validate your threads.  Only a NIST traceable thread mic is acceptable.  Been that way for 40 years at least.


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## MrWhoopee (Apr 12, 2020)

Dabbler said:


> The Canadian military will not accept using thread wires to measure and validate your threads.  Only a NIST traceable thread mic is acceptable.  Been that way for 40 years at least.



Interesting that the Canadian military would specify traceability to a U.S. government agency. Sensible, but still seems odd.


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## DavidR8 (Apr 12, 2020)

MrWhoopee said:


> Interesting that the Canadian military would specify traceability to a U.S. government agency. Sensible, but still seems odd.



Standards know no borders 


Sent from my iPhone using Tapatalk


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## Dabbler (Apr 12, 2020)

MrWhoopee said:


> Interesting that the Canadian military would specify traceability to a U.S. government agency. Sensible, but still seems odd.




pretty simple.  CSA is also specified in contracts, but since everything under the sun is traceable back to NIST, it is specified preferentially.


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