# Any safe way to thread away from my chuck on a South Bend 10K?



## twooldvolvos (Feb 13, 2021)

I'm slowly adding to my lathe skills and its time to make a thread.  So of course I have been doing a lot of reading and viewing videos on line.  I have a burning question.  Is there any safe way to cut threads away from the chuck on a South Bend 10K?  My understanding is that answer is no because I would run the risk of unscrewing the chuck (my chuck is a screw on type).  If this is correct, I will need to learn thread cutting in the direction of my chuck.  I have been too close for comfort to my spinning chuck with my tool post already and it makes nervous to do so.  Any wisdom is appreciated.  Thanks.


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## SLK001 (Feb 13, 2021)

Do you have a way to mount your tool behind your work?  If you were to try (and wanted normal, RH threads), your machine would have to be run in reverse, your tool would have to be upside down and on the back side of your work.

In short, learn FIRST to thread normally.  When threading, the back gears are usually used, so the speed is quite low.  It is really an easy operation to master.  If you have collets for your machine, their use would make threading away from the chuck safe.  Although there are many who say, "I have a threaded chuck and I thread from the chuck all the time...", it is NOT a safe practice.  It's kind of like saying, "I grind my tool bits without safety glasses all the time and I can still see with both eyes..." - a methodology that most would NOT consider safe.  And even if the chuck doesn't come flying off the machine, you still have ruined your work if the chuck comes loose.

As for coming too close to your spinning chuck, are you using your back gears?  Are you using a 29.5º angle on your compound (and feeding the compound)?


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## jcp (Feb 13, 2021)

I have used my collet setup when it's 1/2" or smaller thread. I've also used the 3 jaw chuck, but have since quit. I learned to thread toward the chuck (a long time ago) and it's really no big deal. Start at a low rpm and work your way up. Practice is all it takes.


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## DavidR8 (Feb 13, 2021)

Indeed, threading toward the chuck is not a big deal. 
I’m a novice and I’ve done it without any problems.


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## bill stupak (Feb 13, 2021)

2x on the backgear, use the lowest speed you have along with backgear and practice with a thread pitch around 20 and you'll do fine.


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## mickri (Feb 13, 2021)

I made a chuck keeper (wrong term?) that will hold a chuck in place if I have to run the lathe in reverse.  It is a long rod that fits through the spindle.  The chuck end is a close fit to the inside of the chuck and the outboard end is threaded.  When it is snugged up I can not get the chuck to come off no matter how hard it try.  Another forum member explained how this works.  The two different threads, 8 tpi  on the chuck verses 13 tpi on the keeper, work against each other preventing either from unthreading.


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## twooldvolvos (Feb 13, 2021)

SLK001 said:


> Do you have a way to mount your tool behind your work?  If you were to try (and wanted normal, RH threads), your machine would have to be run in reverse, your tool would have to be upside down and on the back side of your work.
> 
> In short, learn FIRST to thread normally.  When threading, the back gears are usually used, so the speed is quite low.  It is really an easy operation to master.  If you have collets for your machine, their use would make threading away from the chuck safe.  Although there are many who say, "I have a threaded chuck and I thread from the chuck all the time...", it is NOT a safe practice.  It's kind of like saying, "I grind my tool bits without safety glasses all the time and I can still see with both eyes..." - a methodology that most would NOT consider safe.  And even if the chuck doesn't come flying off the machine, you still have ruined your work if the chuck comes loose.
> 
> As for coming too close to your spinning chuck, are you using your back gears?  Are you using a 29.5º angle on your compound (and feeding the compound)?


Thanks for your advice.

I don't have an obvious easy way to put my tool behind the work so I will save that idea for another day.

This is how new I am.  I have run the lathe in back gears just to see if I could make the chuck spin and that's as far as I went.  I hadn't thought to thread in back gears but that is an excellent idea.

As for collets, I do have collets but haven't tried them yet.  I take it that with collets, the draw bar will hold the chuck onto the lathe.  Another good point.


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## mickri (Feb 13, 2021)

You don't use a chuck with collets.  The collets are held in the spindle by the draw bar and you need to have a thread protector on the spindle threads to prevent damage to the spindle threads.

As others have said there is no need to thread away from the headstock.  When I started I used pvc pipe to practice on.  Didn't take long to get the process down.  Maybe an hour at most.

IMHO Mr Pete, aka Tubalcain, is the best source on the web for a beginning hobby machinist.  He is a retired high school shop teacher.  You could start with his beginning videos doing and making what he says and by the time you get through the first couple of hundred of his videos you will be well on your way.  There are lots of other good videos by very knowledgeable people.  But they are random helpful tips on how to do things.  Mr. Pete starts from square one and leads you down the path.  He is still my go to source to brush up on things whenever I run into a problem.


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## Tozguy (Feb 13, 2021)

twooldvolvos said:


> I will need to learn thread cutting in the direction of my chuck. I have been too close for comfort to my spinning chuck with my tool post already and it makes nervous to do so.


As already mentioned use the slowest speed possible. Do not run the chuck in reverse. 
Start with an easy pitch like 16 tpi, or finer, do not thread to a shoulder, use a long enough piece so that the tool holder never gets close to the chuck. Make the situation as easy as possible.
You can even turn the spindle by hand (with power off) at first to build your confidence with the operations.
Its like learning to ride a bike or to swim. You will soon get more comfortable with the operation.


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## SLK001 (Feb 13, 2021)

twooldvolvos said:


> As for collets, I do have collets but haven't tried them yet.  I take it that with collets, the draw bar will hold the chuck onto the lathe.  Another good point.



No, the wording of my answer was unfortunate - "If you have collets for your machine, their use would make threading away from the chuck safe".  What I should have said is, "If you have collets for your machine, their use would make threading away from the headstock safe".  You remove the chuck to use your collets.  If you have the correct size collet, it is the best thing to hold your work with, both toward the headstock and toward the tailstock.

When practicing threading, be sure to support the work from BOTH ends.  Flexing of the work can frustrate a novice to the point of abandoning the hobby.  I don't recommend learning on PVC pipe, since it usually isn't round and it also isn't concentric on the ID and OD, unless you prep the pipe properly (which is also good practice).  It's best to have a nut handy in order to test fit your threads, so practice with the thread pitch of the nut.

Having a SHARP tool of the correct geometry is also mandatory.  Grind a piece of HSS to the correct geometry, then hone the edge to a very fine finish.  DO NOT USE CARBIDE at first.  LEARN to grind your own HSS tool bits.  It is a skill that you will use as long as you have your lathe.


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## Illinoyance (Feb 13, 2021)

mickri said:


> You don't use a chuck with collets.  The collets are held in the spindle by the draw bar and you need to have a thread protector on the spindle threads to prevent damage to the spindle threads.
> 
> As others have said there is no need to thread away from the headstock.  When I started I used pvc pipe to practice on.  Didn't take long to get the process down.  Maybe an hour at most.
> 
> IMHO Mr Pete, aka Tubalcain, is the best source on the web for a beginning hobby machinist.  He is a retired high school shop teacher.  You could start with his beginning videos doing and making what he says and by the time you get through the first couple of hundred of his videos you will be well on your way.  There are lots of other good videos by very knowledgeable people.  But they are random helpful tips on how to do things.  Mr. Pete starts from square one and leads you down the path.  He is still my go to source to brush up on things whenever I run into a problem.


The South Bend 10K has the spindle ground to take a collet directly in the spindle.  It is possible to use a collet and a chuck at the same time.  I have done just that to hols a work stop in the collet.


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## DavidR8 (Feb 13, 2021)

Illinoyance said:


> The South Bend 10K has the spindle ground to take a collet directly in the spindle.  It is possible to use a collet and a chuck at the same time.  I have done just that to hols a work stop in the collet.


Yup I've sucessfully used MT3 collets on my 10K even though the 'official' type is a 6K which are pretty hard to come by.


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## T Bredehoft (Feb 13, 2021)

When I taught threading it was a requirement that the student make a number, 10 to  30 dry passes, (without the tool engaged). This would built (a little) muscle memory into the  operation. Once the hand/eye co-ordination is established (and the speed is slow) threading becomes easy.


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## Aaron_W (Feb 13, 2021)

If you get an ER collet chuck that also reduces the hazard of hitting the chuck. Still not good to make contact but at least you don't have jaws to hit since the chuck face is basically flat. Also since you don't have jaws it is easier to see the solid bits so if you need to cut close to the chuck you can see exactly how far you have left to go. Jaws on a spinning chuck kind of fade into a blur.

I use a red sharpie on the ends of the jaws as well as on the stock I'm cutting to help me see where the jaws are likely to make contact when I need to work close to the chuck.


Edited to add most collets will offer the same advantages, it is not limited to the ER type, but on small lathes ER collets are popular since they can often hold larger stock than many of the in the spindle collets. Most lathes under 11-12" usually can't use 5C collets without a collet chuck.


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## mickri (Feb 13, 2021)

I have 3C collets for my craftsman 12x36 and yes I can still put a chuck on the spindle with a collet in the spindle bore..  But the chuck does not hold the collet in place.  The collet is held in place with a draw bar.

When I practiced threading with PVC pipe all I was doing was learning the process.  The mechanics of threading.  Watch the threading dial to engage the half nuts on the proper line.   Let it run for an inch or so.  Disengage the half nuts.   Back out the cross slide.  Move the carriage back to the starting point.  Move the cross slide in to zero.  Advance the compound and do it again.  Over and over again until I had it down pat.   Both external and internal threading.

I had dykem on the PVC to be able to see the cut.  I would check with a thread gauge to see if I was getting the correct tpi.  As Tom said I was learning the mechanical process.  Spent about an hour doing this and threading is now no big deal.  The next step was practicing with steel until the nut would screw on.  Recently I had to cut a whitworth thread without the benefit of a nut.  This required me to learn how to use wires to measure the thread.  I don't have a thread micrometer and don't plan to buy one.   The wires work for me.  Another skill that I have learned.  But it all started with learning the mechanics on PVC pipe.


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## SLK001 (Feb 13, 2021)

DavidR8 said:


> Yup I've sucessfully used MT3 collets on my 10K even though the 'official' type is a 6K which are pretty hard to come by.



Aren't Morse Taper collets also hard to come by?


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## Aaron_W (Feb 13, 2021)

SLK001 said:


> Aren't Morse Taper collets also hard to come by?



Not as common as some types so they do cost a little more but MT and B&S collets are used on a lot of mills so they are fairly easy to find.

Little Machine Shop MT collets


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## DavidR8 (Feb 13, 2021)

SLK001 said:


> Aren't Morse Taper collets also hard to come by?



For reasons unknown to me there seems to be a bit of a resurgence in MT tooling.


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## jcp (Feb 13, 2021)

It's my understanding that 3C collets (more readily available than 6K) can be used in a 10K by using the 3C to MT2 adapter for the 9" lathes. This will limit you to 1/2" dia. though where use of 6K will go up to 5/8ths.


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## JHerdebu (Feb 14, 2021)

twooldvolvos said:


> I'm slowly adding to my lathe skills and its time to make a thread.  So of course I have been doing a lot of reading and viewing videos on line.  I have a burning question.  Is there any safe way to cut threads away from the chuck on a South Bend 10K?  My understanding is that answer is no because I would run the risk of unscrewing the chuck (my chuck is a screw on type).  If this is correct, I will need to learn thread cutting in the direction of my chuck.  I have been too close for comfort to my spinning chuck with my tool post already and it makes nervous to do so.  Any wisdom is appreciated.  Thanks.


Please watch Joe Pieczynski's video on threading in Reverse Direction gear on youtube.


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## Illinoyance (Feb 14, 2021)

jcp said:


> It's my understanding that 3C collets (more readily available than 6K) can be used in a 10K by using the 3C to MT2 adapter for the 9" lathes. This will limit you to 1/2" dia. though where use of 6K will go up to 5/8ths.


I have a MT3 spindle adapter for 3C collets.  I made an extension for the drawbar that fits 3C collets.  It is not as convenient as using thr 6Ks but my set of 6Ks are in 1/16" steps.  Last time I checked a single 6K from Hardinge was $168.  I can get 3Cs in 1/64 increments a lot cheaper.  Metric, too.


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## Illinoyance (Feb 14, 2021)

Back to the original question.  It is unwise to thread in reverse on any lathe with a threaded spindle.  Torque generated by threading COULD cause the chuck to unscrew.  For small diameter threads it is probably OK if one accepts the risk.  For work held in a collet it is perfectly fine to thread in reverse.


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## Ken226 (Feb 14, 2021)

For anyone intimidated by cutting metric threads to a shoulder, with inch leadscrew and thread disl,  I've been doing it for many years using the method below.

It lets you use both your inch thread dial, and to disengage the half nut at the shoulder.

Adom is quick at it, but he slows down later in the video and shows better shots of the method.






Adoms like a robot doing that.  Very fast.

I run the lathe at a much slower rpm,   disengage the half-nut, then leasurely back out the cross slide.   For me, I back out the cross slide 1 full turn before reversing the spindle.

When the spindles running in reverse, re-engage the half-nut on the same thread dial setting that you started the thread on.   When back to the start of the cut, run the cross slide that 1 full turn in, back to zero.  Then take the next pass, thread dial in the same spot as the first pass

The important thing, is after you disengage the half-nut at the end of each pass, don't let the spindle run long enough for the thread dial to make a full revolution past your mark.   

Back out the cross slide, and stop the spindle, then reverse it so you can engage the thread dial on the same mark.  As long as the thread dial didn't go a full revolution, the same mark will mean the same thread, in exactly the same spot.


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## twooldvolvos (Feb 19, 2021)

JHerdebu said:


> Please watch Joe Pieczynski's video on threading in Reverse Direction gear on youtube.


I wish I could use this technique but my understanding is that it is unsafe running a lathe like my South Bend 10K in reverse since the chuck is screwed on and I risk it unscrewing with tool pressure.  Am I missing something?


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## twooldvolvos (Feb 19, 2021)

SLK001 said:


> No, the wording of my answer was unfortunate - "If you have collets for your machine, their use would make threading away from the chuck safe".  What I should have said is, "If you have collets for your machine, their use would make threading away from the headstock safe".  You remove the chuck to use your collets.  If you have the correct size collet, it is the best thing to hold your work with, both toward the headstock and toward the tailstock.
> 
> When practicing threading, be sure to support the work from BOTH ends.  Flexing of the work can frustrate a novice to the point of abandoning the hobby.  I don't recommend learning on PVC pipe, since it usually isn't round and it also isn't concentric on the ID and OD, unless you prep the pipe properly (which is also good practice).  It's best to have a nut handy in order to test fit your threads, so practice with the thread pitch of the nut.
> 
> Having a SHARP tool of the correct geometry is also mandatory.  Grind a piece of HSS to the correct geometry, then hone the edge to a very fine finish.  DO NOT USE CARBIDE at first.  LEARN to grind your own HSS tool bits.  It is a skill that you will use as long as you have your lathe.


Ha.  Ha.  Good catch.  There is no chuck involved when using collets.  I understood what you were trying to say without noticing any problems with the wording.


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## mickri (Feb 19, 2021)

As I said in my previous post #6 make a chuck keeper.  It will prevent the chuck from unthreading when running in reverse.


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## twooldvolvos (Feb 20, 2021)

mickri said:


> As I said in my previous post #6 make a chuck keeper.  It will prevent the chuck from unthreading when running in reverse.


Mickri.  Good point.  Being a newbie and wanting to add thread cutting to my resume, I am considering coming up with a chuck keeper and beginning my thread cutting career cutting away from the chuck or using collets.  I really don't want to run my tool post into my chuck, but then who does?


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## Ken226 (Feb 20, 2021)

Is running the toolpost
into the chuck a common thing?  

I haven't done it a single time since I bought my first lathe in 2007.   Perhaps I've been lucky.


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## mickri (Feb 20, 2021)

This hobby is not for the inattentive.  You have to keep track of what you are doing.  Threading towards the chuck is no different from turning towards the chuck.  If anything threading is easier to keep from hitting the chuck because as soon as you release the half nuts the carriage stops moving.  Whenever I do anything on my lathe I always do a dry run by hand looking for anything that might hit the chuck.  I spin the chuck with my left hand while I move the carriage towards the chuck with my right hand.  I then change my setup if I have to.  The closest that I come to the chuck is when doing internal boring because you want to keep the boring bar as short as possible.  I get really close sometimes.  Within an 1/8" at times.   I should probably turn away from the chuck when boring.

Don't let this stress you out.  A little preplanning and you will be fine.


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## Dabbler (Feb 20, 2021)

@twooldvolvos @SLK001 the advice that @mickri is giving is golden.

Even Joe Piecyznski will tell you to never thread away from  the chuck if you have a screw on chuck.  Joe is on the forum here from time to time, and I hope he chimes in on this thread.

I know that some of our best British friends have made innovative ways to 'keep' the chuck on the lathe including that neat drawbar suggested by @mickri but these devices are more in an 'intermediate to advanced' operators.  Take their advice and get used to threading the normal way before trying to use the variants on your threaded spindle.

As a matter of safety and protection for your lathe, the cuts you take for threading should be in the order of .004-.005, so you can slack off the drive belt in case the 'bad thing' happens..  I won't prevent all damage, but it will take care of the worst of it, especially at 150 RPM.


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## mickri (Feb 20, 2021)

I must have my drive belts too loose.  It doesn't take much to stop the spindle from turning on my lathe at 28 rpm that I use for threading.


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## RJSakowski (Feb 20, 2021)

I loosen my drive belt sometimes when I want to control the spindle torque. It comes in handy when winding coils or making springs.  Also useful when threading small threads or up to a close shoulder.


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## twooldvolvos (Feb 20, 2021)

Dabbler said:


> @twooldvolvos @SLK001 the advice that @mickri is giving is golden.
> 
> Even Joe Piecyznski will tell you to never thread away from  the chuck if you have a screw on chuck.  Joe is on the forum here from time to time, and I hope he chimes in on this thread.
> 
> ...


Your comment, "150 RPM" is a good reminder.  Using back gears will make cutting threads much more manageable for me as a beginner.  Several others have offered the same wisdom.


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## mickri (Feb 20, 2021)

The true machinists amongst us can thread at faster speeds.  On the other hand us newbies to machining need to thread at the slowest speed that our lathe will turn.  That's 28 rpm in my case.  Until recently I have only used 28 rpm for threading and 166 rpm for everything else.  Did some reading in the MOLO and found for most of what I do which is turning steel I should be a 266 rpm on my lathe.  I occasionally venture up to 418 rpm.   Slow is better starting out until you gain more experience operating your lathe.  JMHO


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## Ken226 (Feb 20, 2021)

mickri said:


> The true machinists amongst us can thread at faster speeds.  On the other hand us newbies to machining need to thread at the slowest speed that our lathe will turn.  That's 28 rpm in my case.  Until recently I have only used 28 rpm for threading and 166 rpm for everything else.  Did some reading in the MOLO and found for most of what I do which is turning steel I should be a 266 rpm on my lathe.  I occasionally venture up to 418 rpm.   Slow is better starting out until you gain more experience operating your lathe.  JMHO



This is excellent advice.    For someone just starting out learning to cut screw threads,  its not the time to look for tricks.   Practice using the standard old methods,  slowly.  As you get better at it, you can start going faster.   When your really good at it,  you can start trying new things.

Like learning to drive a stick-shift first,  or learning to use dials before switching on the DRO. 

If someone starts out cutting threads backwards and upside down,  at what point are they going to learn the normal methods?

My first few attempts at learning to thread weren't even done under power.   I turned the chuck by hand,  or on coarse, deep threads, i used a crescent wrench on the chuck jaws to rotate the spindle.

My advice to someone just starting out, would be to grind their tools from hss blanks,  leave the DRO off and thread toward the headstock.


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## twooldvolvos (Mar 26, 2021)

Ken226 said:


> This is excellent advice.    For someone just starting out learning to cut screw threads,  its not the time to look for tricks.   Practice using the standard old methods,  slowly.  As you get better at it, you can start going faster.   When your really good at it,  you can start trying new things.
> 
> Like learning to drive a stick-shift first,  or learning to use dials before switching on the DRO.
> 
> ...


Thanks for your wise advice.


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## epanzella (Mar 27, 2021)

When I first got my lathe I was nervous threading towards the chuck so I wanted a slower speed than my minimum 70 rpm. I didn't have the skill to build a speed reducer yet so I just did whatever I could to learn. By the time I had the experience to build a speed reducer I also had the experience to thread towards the chuck so the problem solved itself!


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## Watchwatch (Mar 27, 2021)

Ken226 said:


> This is excellent advice. For someone just starting out learning to cut screw threads, its not the time to look for tricks. Practice using the standard old methods, slowly. As you get better at it, you can start going faster. When your really good at it, you can start trying new things.
> 
> Like learning to drive a stick-shift first, or learning to use dials before switching on the DRO.
> 
> ...




I learned to thread towards the chuck way back when. At home, I thread away from the chuck.

What’s the downside to threading away? Only one I can think of is buggering a thread if you don’t hit your mark. You don’t have a chance to to bail out before the tool cuts. Scrap part.

On the flip side, threading towards the chuck can be very expensive if you mess up. Or worse. I’d rather scrap a part than a lathe.

JoePi only threads away and he has made a living at it for 40+ years. 


Sent from my iPhone using Tapatalk


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## Winegrower (Mar 28, 2021)

For external threads, whether threading toward the headstock, let’s say “normal”,  or away, “reversed” is not a big deal as some of you say.   But where reversing really saves the day is in cutting internal RH threads in a deep blind hole.  I had to do that recently, and because the diameter was small, i had to make a smaller holder for a lay down insert.    It’s a normal insert you could use for external threading, but the holder is left hand and you turn in reverse, cutting on the far side of the hole.   You just run the tool deep into the hole using a dro, a dial indicator or just a carriage stop, take all the time you want, advance the cross slide to the next pass thread cut depth and engage the half nut normally.   

Otherwise, timing when to disengage the half nut when cutting toward the bottom of a blind hole kind of turns this hobby into work.


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## Ken226 (Mar 28, 2021)

Quote from @Watchwatch :
"What’s the downside to threading away? Only one I can think of is buggering a thread if you don’t hit your mark. You don’t have a chance to to bail out before the tool cuts. Scrap part."



I didn't say that there was a downside.  I said:

"For someone just starting out learning to cut screw threads, its not the time to look for tricks."

By that,  I just meant that "someone just starting out, learning",  should learn to thread backwards untill he learns the textbook way.   That method shouldn't be learned at the exclusion of learning the textbook method.

Sorry,  I should have been more clear.

As to downsides of away, and upside down threading.  Of course there are downsides.  Minor, but they exist.


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## Ken226 (Mar 28, 2021)

As to downsides of threading upside down.

The lathe was designed with the intent that the cutting forces be directed downward, into the tool, though the toolpost, compound and cross slides, then into the bed-ways.      Because of this, they designed the compound and cross slide dovetails with the flat, precise, oily, load bearing surfaces facing up, to absorb these forces with minimal wear.
They put the angled surfaces of the dovetails, and the gibs below, away from cutting forces.  Since the angled surfaces and gibs are designed control alignment and sliding clearances, the designers decided to put them where they would be subject to less cutting forces and wear.

The bed-ways were put on top of the bed, for the same reason.  Cutting forces end up transmitted into the hardened, precision ground, polished and oiled bed-ways.



When you cut upside down and backwards, the forces are imparted upwards on the tool.  In the lifting direction.   So, the cutting forces are no longer transmitted through the precision ground, polished and hardened surfaces,  but are transmitted through the much smaller  angled dovetail surfaces and gibs. (p=f/a or pressure=force divided by area).    So, in that simple formula p=f/a,   when you reduce the numeric value for the denominator (a),  you increase the value for p.    So the same cutting forces result in significantly more pressure on lathe parts, and it is transmitted into parts that are not hardened, precision ground, and scraped to hold oil.

Also, consider.  The final point where those forces are transferred into the bed, is the gib on the underside of the front of the saddle.  That force is transmitted with an upward vector, and with a much higher value for p, due to that gibs much smaller value for a.  In most of your (and my) lathe's, that gib isn't hardened,  and in some cases, as it wears, it's not adjustable,  but may need replaced if it wears sufficiently that the saddle starts to lift while threading backwards.


Now, all that being said,  I still believe those are very minor downsides for most hobby machinists.    Because we're threading with low cutting forces, finer pitches, and infrequently enough to wear things out with those low cutting forces.

I wouldn't be a bit afraid to thread upside down for most stuff. But if I were going to be threading a few hundred 1 foot long rods with 4 pitch ACME threads, I wouldn't do it.   Or if I had a small lathe with non adjustable and/or hard to replace saddle, cross slide and compound rest gibs, I might not want to use that method.

For some, perhaps the juice is worth the squeeze.  Some circumstances may allow for it, but other circumstances may not.




Another consideration is lathe design.  I don't know much about Southbend Lathes but I recall a post on practical machinist indicating that they do not have a frontside undermount gib to prevent lifting.   

Quote from a post on Practical Machinist:

"The smaller SouthBend lathes, 9" & 10" at least, don't have anything at the front of the saddle to prevent lifting. Just a bolt on gib strip under the rear shears.".

Im not familiar with Southbend, and have no idea what, or where the "rear shears" are, but If this is true, those Southbend models and any others sharing that design, might not give the best results if one chooses to thread upside down using one.


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## Toolmaker51 (Mar 28, 2021)

mickri said:


> View attachment 355329





mickri said:


> I made a chuck keeper (wrong term?) that will hold a chuck in place if I have to run the lathe in reverse.  It is a long rod that fits through the spindle.  The chuck end is a close fit to the inside of the chuck and the outboard end is threaded.  When it is snugged up I can not get the chuck to come off no matter how hard it try.  Another forum member explained how this works.  The two different threads, 8 tpi  on the chuck verses 13 tpi on the keeper, work against each other preventing either from unthreading.


This is a clever solution. Not sure of it being fail-safe, but certain at least chuck won't leave spindle.  I don't have any threaded spindles that are powered; but can relay this. A right hand [not even large] end mill cutting a transverse slot can unscrew chuck on an indexer.......


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## Toolmaker51 (Mar 28, 2021)

Adding this, perfect for this thread [pun intended? IDK]. 
Juggling machine design, part requirements, available tooling is part of every project; to the point no clear way to distinguish what order to consider those. Regarding tool positioning though, offering this. Sorry, no clearer way to format this is known, even tried color coding to no avail. Initial breakdown starts with external or internal threads, then whether RH or LH.
I literally hold out a finger [OD] or thumb and finger [simulating ID], anticipated tool bit in other hand.

A - Threading tool upright, point toward lathe back
B - Threading tool inverted, point toward lathe back
C - Threading tool upright, point toward lathe front
D - Threading tool inverted, point toward lathe front

L - Direction of feed = Left
R - Direction of feed = Right
f - Forward Spindle Rotation
r - Reverse Spindle Rotation

To Cut Right Hand External Threads: Lf(A/D) Rr(B/C)
To Cut Left Hand External Threads: Lr(B/C) Rf(A/D)
To Cut Right Hand Internal Threads: Lf(B/C) Rr(A/D)
To Cut Left Hand Internal Threads: Lr(A/D) Rf(B/C)


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## Alter Machine (Mar 30, 2021)

I would always complain that apprentices were taught to drill too fast and thread too slow they lacked the confidence to terminate the thread at a shoulder at 300rpm but had no qualms about ramming a 1" at 500rpm into a piece of steel dry. 
YOU are a hobbyist there is no such thing as too slow. try shadow machining first. This where you leave the tool an .100-.500 away from the part and start at a reasonable speed say 150-200rpm (slower if need be) and practice you movements, engaging on the right division disengagement and pullout; returning to the start of the thread and finding zero, make your adjustments to your compound or cross-slide (depending on your methods); rinse and repeat. go slow enough and take light enough cuts to avoid using oil/coolant it can be quite dramatic for some learning to thread with smoke or flood obscuring their vision.
As your experience grows you will learn the most of the limitations you encounter will be that of the machine and not the operator.


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## Ken226 (Mar 30, 2021)

Alter Machine said:


> I would always complain that apprentices were taught to drill too fast and thread too slow they lacked the confidence to terminate the thread at a shoulder at 300rpm but had no qualms about ramming a 1" at 500rpm into a piece of steel dry.
> YOU are a hobbyist there is no such thing as too slow. try shadow machining first. This where you leave the tool an .100-.500 away from the part and start at a reasonable speed say 150-200rpm (slower if need be) and practice you movements, engaging on the right division disengagement and pullout; returning to the start of the thread and finding zero, make your adjustments to your compound or cross-slide (depending on your methods); rinse and repeat. go slow enough and take light enough cuts to avoid using oil/coolant it can be quite dramatic for some learning to thread with smoke or flood obscuring their vision.
> As your experience grows you will learn the most of the limitations you encounter will be that of the machine and not the operator.



My first hundred or so times cutting threads were during "practical lab" exercises.  The last semester for a degree in Mechanical Engineering Technology, taking the technical elective called Manufacturing Methods and Practices.  

That's how the instructor had us practicing.  Air cutting until confident. Then a scratch cut over layout fluid.   He'd come around and check the pitch, and make sure the helix terminated in a circle at the right distance from the part face.

The goal was that the student could terminate the helix within a few thousandths of the specified distance from the face of the shaft, without the circular termination cut being too wide.  1 scratch cut pass,  .005" deep, then 10 more passes @ the same dial setting over top of the scratch cut.   There had to be 1 helix, terminating in 1 circle.

I seem to remember the acceptable width of that termination mark being unreasonably tight and pretty difficult to hit,  with 10 scratch passes @ the same .005" deep setting.

It was kinda fun, competing to hit the narrowest termination mark, closest to the specified length of cut.


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## Toolmaker51 (Mar 30, 2021)

Having been single point threading for _decades, _those first passes in layout blue make all the difference. Not just pitch - hand combination, but tool clearance of holders to chucking, carriage with tailstock, the whole set-up. Pitch is a big deal, like why lathes geared for 2 TPI have 20 or 30 low RPM, not to mention the larger diameters involved.
Fortunately, [considerately?] machine engineers allow RPM changes without disturbing initial sync of lead screw. Get dialed in, bump it up.
Far as a mark being unreasonably tight and pretty difficult to hit, it's reasonable being apprehensive with new challenges. That is learning.

My post above, #43 lists each tool orientation - spindle rotation - leadscrew rotation for internal/ external threading, that apply equally turning to a shoulder, O-ringing, snap ring grooves, etc. Print wise, those have narrower yet allowances for error.


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## Ken226 (Mar 30, 2021)

The last semester for that program was a helluva lot of fun, but challenging too.   One of the most challenging things I've done. 

 Engineering Mechanics, Mechanical Design 1, Mechanical Design 2,  Manufacturing Methods and Practices,  Machine Tool Design,  and of course, "Industrial Psychology!".  There were no practical labs for Industrial Psychology though


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## ttabbal (Mar 30, 2021)

Ken226 said:


> There were no practical labs for Industrial Psychology though




I just had an image of Sigmund Freud sitting next to a lathe "Tell me about your gearing.. "


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## Toolmaker51 (Mar 30, 2021)

Separately, few things are more irritating regarding language, than free use of the term 'Technology'. More hype than fact.
Schools, advertising, general speech go wild, pasting it on anything that moves.
Ladies make-up? No, that's chemistry. Manual Machine Tools? No, simple mechanics and bare physics. No Iron Pants? No, just textiles. Kitchen appliances? No, electrical and electronics. You get the idea. Most don't even have technology involved in the manufacturing of same.
Farthest that Technology as a 'thing' reaches, in many cases, is merely development process.

But what about, lets say, stress and load tables of structural engineering? Or aircraft? Well, again not primarily. Those figures were established long ago by experience and slide rules. Technology has pared every spare ounce of material, that extra 10-15% everything had making it last forever.

Wish I had a dime for every "but Technology is critical or does so-and-so......" comment I answered "Ok, then how'd they build Golden Gate Bridge?"
Not to sound tech-phobic! Hell no, lol.

PS. Editing toward inbound posts during my essay. 
Industrial Psychology? Good Grief! Spend more time worrying about those poor unfulfilled cubicle gophers!


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## Ken226 (Mar 30, 2021)

And that was a couple decades ago.   Imagine what it's like now!


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## Toolmaker51 (Mar 30, 2021)

Ken226 said:


> And that was a couple decades ago.   Imagine what it's like now!


Imagining not required. Just watch "_The Office", _live version to what Scott Adams conceived with _"Dilbert". _
Just like when neurotic swivel chair jockeys, engineering aides with company credit cards and/ or expense accounts I know, want to borrow a caliper.
Sure thing! 
As I hand them a box with  a Starrett #123  model vernier.
While I continue doing whatever with a digital caliper .


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## main_cogg (Mar 30, 2021)

You're nicer than I was to them. When they asked me to borrow calipers,  I'd say " sure, inside or outside?" and pull these out of a drawer.


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## Toolmaker51 (Mar 30, 2021)

I'm nicer? Lol. Spring calipers though, pretty damn funny. 
I wonder _how many _look at those, (what appears to us as simple logical mechanical device) but can't analyze the operation.
Indeed, _how many_ is not known. I'm positive there's more every day.


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## Ken226 (Mar 30, 2021)

Toolmaker51 said:


> I'm nicer? Lol. Spring calipers though, pretty damn funny.
> I wonder _how many _look at those, (what appears to us as simple logical mechanical device) but can't analyze the operation.
> Indeed, _how many_ is not known. I'm positive there's more every day.




How many indeed!  At the current rate of decline of the number of people who alive who can do such things,  it should soonbreach it's an asymptotic minimum..   the average IQ has been declining since the Victorian era.

I watched a documentary a few years ago.  It was kinda funny, prophetic, and terrifying, all at the same time.   Some of the absurd things from that show, I've since, seen come to pass.   The hospital scene reminds me of every fast food place I've been recently.

I think it was called "Idiocracy".


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