Single point vs. die threading

[martik777]

When cutting standard size threads I usually use a die in the tailstock but I'm wondering how much more accurate single pointing the same thread would be.

Has anyone done some actual tests?

 

[Tony Wells]

Much more accurate. For nuts and bolts, studs, utility threads, dies are probably sufficiently accurate. Also much easier to do very small threads with a die.

There are features of threads that you may want to control independently, where a die will not allow that. You may want a special pitch for a one time job.....no die practical. You have much, much better control of the PD when single point threading. Major, minor and pitch are all under your control individually with single pointing. Not so with a die. When a die gets dull, yes, you can sharpen it, and some are adjustable to a degree, but no comparison with single pointing.

Main feature to differentiate, to me, is the axial alignment. With a single point tool, it is near dead on accurate as far as concentricity goes. With a die, in my experience, they tend to drift off center, and there is only so much you can do to correct or minimize it.

 

[martik777]

Thanks, I always thought if you started the die on center it would be almost as accurate but never considered that it would drift off center. Speaking of control and small threads, I recently cut an 80tpi .055 OD screw for a broken eyeglass frame, just kept checking the fit after each pass - amazingly, I was able to single point with my regular 1/4" HSS thread toolbit.

 

[churchjw]

Thanks, I always thought if you started the die on center it would be almost as accurate but never considered that it would drift off center. Speaking of control and small threads, I recently cut an 80tpi .055 OD screw for a broken eyeglass frame, just kept checking the fit after each pass - amazingly, I was able to single point with my regular 1/4" HSS thread toolbit.

I would love to see that. It is so far out of my ability range it sounds like magic. :man:

Jeff

 

[epanzella]

Thanks, I always thought if you started the die on center it would be almost as accurate but never considered that it would drift off center. Speaking of control and small threads, I recently cut an 80tpi .055 OD screw for a broken eyeglass frame, just kept checking the fit after each pass - amazingly, I was able to single point with my regular 1/4" HSS thread toolbit.

Wow! Would luv to know how you did that. I can hardly even see a screw that small and have my hands full just reinserting one into my glasses if it falls out.

 

[RandyM]

I would love to see that. It is so far out of my ability range it sounds like magic. :man:

Jeff

This makes two of us. Show us your craftsmanship.

 

[pestilence]

Thanks, I always thought if you started the die on center it would be almost as accurate but never considered that it would drift off center. Speaking of control and small threads, I recently cut an 80tpi .055 OD screw for a broken eyeglass frame, just kept checking the fit after each pass - amazingly, I was able to single point with my regular 1/4" HSS thread toolbit.

ARE YOU A WIZARD?

 

[martik777]

I created a new thread:

http://www.hobby-machinist.com/show...screw-055-quot-OD-x-80TPI?p=148181#post148181

 

[Bill C.]

Thanks, I always thought if you started the die on center it would be almost as accurate but never considered that it would drift off center. Speaking of control and small threads, I recently cut an 80tpi .055 OD screw for a broken eyeglass frame, just kept checking the fit after each pass - amazingly, I was able to single point with my regular 1/4" HSS thread toolbit.

It depends on the type of die you are using. The heavy snap open threading dies don't drift. The smaller hand dies, most of us have used, could drift since they were design to be used with a tee handle. I used them to clean up rough threads.

 

[Tom Griffin]

Everything about a lathe cut thread is better than a die cut thread. The lead is more consistent, the diameter is more precise, and there is no comparison on the surface finish. If you are making a screw to fix the lawn mower, a die would suffice. Pretty much everything else should be single pointed.

Tom