# threading small rod help needed



## crueby (Nov 1, 2013)

Looking for some tips on getting threads to go straight on small rod stock (1/8", 1/16"). Using a hand held die holder, seems like whatever I do the thread winds up wandering to the side, getting deeper on one side than the other.

There are several other ways to thread - threading setup on lathe, using tailstock die holder, etc. Question for you guys - which way works best? Does putting the die into a holder on the tailstock help with this problem? Or is getting a threading tool setup for my lathe the way to go? Or some other tricks/tips? I tried searching the forums, but words like 'threading'/etc are in just about every post!

Thanks!


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## Steve J (Nov 1, 2013)

I use a die handle and back it up with a jacobs chuck in the tailstock. back the chuck jaws all the way in and use the body of the chuck to apply pressure and keep the die square. I also found that stainless welding rod works better than mild steel. the mild steel would gall and the threads would strip off.stainless would thread fine. Also i only ever went down to 1/8 with 5-40 threads.


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## Philjoe5 (Nov 1, 2013)

I just finished putting 4-40 threads on the end of a stainless steel rod that was 1/8" in diameter and about 1 1/4" long.  I turned the end of this rod to a diameter of between 0.109" - 0.110" for a length of about 3/8".  I used a round die held in a tailstock dieholder and got good results.   Put the spindle of the lathe in a freewheel state and simultaneously turn the spindle while feeding the tailstock with a very slight amount of pressure.

I had to make three of these and I ended up with a few rejects.  The rejects had been turned down to a diameter of 0.112" which is the major diameter for this thread.  My past experience has been that best results come from diameters that are just under the major diameter of the threads you're trying to cut.  I had thought I could get away with going to 0.112" on this small a thread.  Nope!

Cheers,
Phil


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## abby (Nov 1, 2013)

Most people will have experienced the problem you are having when using split dies and a tailstock die holder will help, but keeping the die square using the tailstock is as good.
More important make sure the die is sharp , if slightly blunt it will cut more on one side with the same results.
Carbon dies are cheaper than HSS but if you are intending to stick with the hobby get HSS , they will last a lifetime if used carefully.
Put a lead on the bar /rod to start the thread and adjust the die on the large side , take more than one cut to get down to the fit you require , use plenty of tapping oil , lube oil is useless.
I make lots of special bolts and screws as small as 10 BA and have found a coventry die head invaluable , the sets of chasers can often be found on Ebay for less than the price of a split die.
*http://youtu.be/Y-r7mEnJmNo
*


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## crueby (Nov 1, 2013)

Philjoe5 said:


> I just finished putting 4-40 threads on the end of a stainless steel rod that was 1/8" in diameter and about 1 1/4" long.  I turned the end of this rod to a diameter of between 0.109" - 0.110" for a length of about 3/8".  I used a round die held in a tailstock dieholder and got good results.   Put the spindle of the lathe in a freewheel state and simultaneously turn the spindle while feeding the tailstock with a very slight amount of pressure.
> 
> I had to make three of these and I ended up with a few rejects.  The rejects had been turned down to a diameter of 0.112" which is the major diameter for this thread.  My past experience has been that best results come from diameters that are just under the major diameter of the threads you're trying to cut.  I had thought I could get away with going to 0.112" on this small a thread.  Nope!
> 
> ...



Good tips - thanks!


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## crueby (Nov 1, 2013)

abby said:


> Most people will have experienced the problem you are having when using split dies and a tailstock die holder will help, but keeping the die square using the tailstock is as good.
> More important make sure the die is sharp , if slightly blunt it will cut more on one side with the same results.
> Carbon dies are cheaper than HSS but if you are intending to stick with the hobby get HSS , they will last a lifetime if used carefully.
> Put a lead on the bar /rod to start the thread and adjust the die on the large side , take more than one cut to get down to the fit you require , use plenty of tapping oil , lube oil is useless.
> ...



Interesting - had never heard of that type of die before.


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## petertha (Nov 1, 2013)

abby said:


> I make lots of special bolts and screws as small as 10 BA and have found a coventry die head invaluable


 
Thats really neat. Is it your own design or off plans or?

Can you elaborate on what/any push force on the die? Does the rotating stock draw it in on its own once threading, or slight spring pressure from behind etc?


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## crueby (Nov 25, 2013)

Did some experiments after getting your advice - I dont have a tailstock dieholder yet (on my to-make-soon list now), so tried it the other way around. Chucked up a length of 1/8" steel rod in the drillchuck held in the tailstock, but left the tailstock little loose on the bed, and held the die in the lathe chuck on the headstock (die up flat against the chuck face to make sure it was square).

Turned the headstock by hand while pushing in on the tailstock, and it cut perfectly straight set of threads.   Keeping the die straight to the rod was definitely the problem in my case. Gotta make a tailstock holder for it - found several different designs, does not look too hard.

Thanks for the help guys! (gals? its? whatever!)


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## Philjoe5 (Nov 25, 2013)

I've also gotten good results using a hex rethreading die held in a diestock.  In this case it's essential to turn the OD a few % less than the major diameter of the thread.  

Then, with a drill chuck in the tailstock to apply some pressure to the die held in the diestock, rotate the spindle and simultaneously advance the tailstock.  After a few full threads have been cut you can then finish the job by turning the diestock and it will follow the threads you've cut.

Cheers,
Phil


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## Swifty (Nov 26, 2013)

You will find using a die holder in the tailstock will solve all your problems. Their very easy to make.

Paul.


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## kd0afk (Nov 29, 2013)

It's not automatic or fancy but here is my solution to threading. Got the idea from Greg Halligan on YouTube.


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## gus (Nov 30, 2013)

Here is how I thread piston rods. 3/4/5 mm brass rods best for threading. I use Japanese Dies bought from TokyuHands. Tapmatic Tapping Fluid is great for threading.A reversible ratchet spanner makes manual threading on the lathe easy
Thread dies must be in good condition to form good looking threads.
For long threaded rods I use die holders and thread on bench vise.

Manual Tapping on the lathe is made easy with Reversible Ratchet Spanner and Tapmatic Fluid.Hex brass nut Loctited to tap so as to use Ratchet Ring Spanner.


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## crueby (Nov 30, 2013)

Clever use of the ratchet - great idea!


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## gus (Dec 1, 2013)

crueby said:


> Clever use of the ratchet - great idea!



Hi Crueby,

A Tail Stock Die Holder and Tap Holder cost "Arm & Leg" landed in Singapore.
"70 Young"  had plenty of idle time to burn and $$$$ to save and buy other 
tools that he can't make.

Been fun making DIY Rotary Table, Fixed Steady Rest, Dividing Head for Gear Cutting etc.So much to do and so little time and energy left.

Week-ends take friends out fishing.Last week end was not to bad. Took home some expensive fish to feed my family. Been blessed with good health and family.


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