triple start tap and die set -how to

[studioso]

hi,
so I finally got around trying the tap and die purchased by the group (thanks Joe), on the clear cheap acrylic rod (thanks George) and I'm having some trouble.

talking about the die, I assumed that I needed between .450 and .470 ( I tried 4 different width within that range) width to make a decent thread, tapered the first 1/16th or so, I lubed with wd-40, made sure to back up half a turn after every turn, and still I had no good peaks: I don't have a picture handy but it looks like a stripped bolt- no rough surfaces but just valleys, no peaks it looks (and feels) like I was stripping the thread at some point of the operation.

what am I doing wrong?
-is there an issue with backing up the die too often? is it necessary to stop every few threads to take off the die and clear any chips inside?
-I use this die holder from little machine shop which slides on the arbor that fits in the morse taper. is it OK to lock to tailstock the bed? does it matter if the ram is unlocked?

on a separate note: what's your good method (and tool) to get a nice uniform width on the blank?, without tapers, so to speak?

I'm sorry for asking all these questions at once, just figured all the info necessary to use the set can go in this thread.


thanks for reading

 

[Manny]

Pictures pictures pictures

The acrylic rod you are talking about takes some practice. I had cracking issues using a 1/2 x 20 die. I have not tried my new tap and die set on that acrylic yet.

First to basics - is the die facing the right direction? Writing should be facing out.

I don't have issue backing the die on and off.
I use the same die holder
I leave my tail stock loose with light pressure while threading and no pressure at all when backing off.

Different materials require backing off differently. Generally I back my die off after 1 or 2 revolutions are when I feel the die start to choke.

Straight cuts are done on my metal lathe. Dunno how you would do it on a wood lathe. maybe a parting tool?

I find pam to be a great lubricant

Usually when I see a stripping effect it is due to me make too large of a tenon and the die just grinds it without grabbing it and pulling forward.

I am sure other more seasoned turners will give more insight

Manny

 

[soligen]

+1 on using Pam.

On the diameter, The die is adjustable, so it's hard to say what is correct for you, as it depends on its adjustment. For me, a diameter of 11.8mm works well on Alumilite.

To get to 11.8, Parting tool to get close, then I just go real slow with my woodchuck (R2 insert) and use the calipers often.

I dont have the same die holder, so can't comment there.

If the diameter is too big, I get chip out in the threads - which is a bummer.