Threading problem.

[Arnak]

Hi Folks,

I have a strange problem with threading that I have never encountered before.

Using a 7/32" ME Die in a tailstock holder I was attempting to put the thread on a piece of mild steel.

Tapping started OK but as I progressed it got harder to turn the die, so I backed off a bit and found that the thread was mangled up.

I continued to attempt to thread the rod and noticed that the thread was forming at the front end of the die and not to bad behind it but once I tried to reverse the die the thread once again became very damaged and reduced in size. ???

I checked the die which as far as I could see was reasonable, I had the gap opened as much as I could and the steel was only slightly a few though undersized.

In all I made 3 attempts to cut the thread but they all came out bad on 3 pieces of steel.

Any ideas as to what could be causing that.

I have ordered a new die just in case.

Arnak

 

[Chitownmachine]

Chipped tooth? If its an old die, is the lead worn? Other wise got me!! Lemme know how it goes

 

[rake60]

What is the actual diameter of the material being being threaded?

When I'm using a die, I usually cut it .005" to .010" under the nominal size.
If it is at the nominal size the die would be trying to cut the thread to sharp points.
That rarely works out well.

Rick

 

[tel]

Sounds like a dodgy die to me. I had a 2BA one that persisted in doing something very similar. Replacing it fixed the problem.

 

[Herbiev]

Just a guess, but does that size come as a taper die?

 

[fcheslop]

I had the same problem with some dies from Tracy Tools the taps are great but the 9/32 and 5/16 by 40 would not cut a decent thread occasionally if a long lead was put on the job they would cut but the thread was always undersize
best wishes Frazer

 

[Arnak]

Hi Guys,

Thanks for the replies.

From your replies I must assume that it is the die, a new one is on the way.

I did try with a piece of stainless steel that was exactly 7/32" and the result was the same.

Hopefully, with the new die I should be back in business.

Arnak

 

[Maryak]

I did try with a piece of stainless steel that was exactly 7/32" and the result was the same.

Arnak

Glad you ordered a new one. ;D

Best Regards
Bob

 

[Ned Ludd]

Hi Arnak,
Two things to suggest;
1/ are you sure the die is sitting squarely in the holder? I often tap the die with a rubber hammer to make sure it is sitting firmly in place. Don't assume that the screws will locate the die correctly.
2/ If the die is sitting correctly, try putting the die in a standard hand operated die holder and use the tail stock quill end face as support to keep the die square to the work.
Dies are usually meant for hand operation and using it this way it does not need the thread cutting part to be in the centre of the die. By holding the die too rigidly in a tailstock die holder you can find that you are cutting with only part of the die, causing it to cut under size.
Ned

 

[Ken I]

Just a couple more points.

You said you had the die opened up as much as possible - the screw "opening" it can work loose or fret if it is taking the load causing the die to slowly close as you work it - then it cut on its entire face and will start tearing - particularly on reversal.

Use all the securing screws - not just the expanding screw.

If its tearing on extraction, try forcing the die wider before unscrewing.

Reduce your OD - cutting to full diameter invariably introduces tearing.

2c

Ken