Gallery, Projects and General > How do I??

Is this Die made improperly?

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SPiN Racing:
Evening all,

I wasnt sure if this is the right section. BUt I figure it works in How Do I.. because soo many things I am a complete novice at.

Yes I have used Dies before, and Taps. I have since I was little.. but most of the things I used them for were repairing somethign that wasnt very presice.

Machining.. And wanting to tap something, or Cut external threads with a Die... you kinda need to do it precisely.

I kinda feel like Im drawing it in CAD.. marking it with a thick Sharpie, and cutting it with a plasma cutter.


Anyhow... so the thing is... With the fan pull I made for my mom, I realised that the threads I cut in the end were offcenter. The drill and tap job in the brass was centered though.
It dawned on my I am very likely doing something wrong... OR the Die is actually crappy, not just a cheap cheap cheap die.. but a crappily cut one too.

This is the Die in the holder.


Here we have it flipped over,


And again



Now here is how I was cutting threads in a shaft with the die.
My method is basically to close the jaws of the chuck so that they are centered in the opening on the Die Holder, then move the tailstock so its against the part I am cutting the thread into.
I then crank the 3 jaw by hand with some RapidTap in the Die, and on the part.
As I crank the 3-jaw, I run the tailstock in so it stays lightly snug, and keeps the die square.








And here is a clip of a stainless shaft I cut threads into, with the die in the 3-jaw. The other end of the shaft is snug enough to lightly drag in the drill chuck in the tailstock. The shaft is around 8 inches long.

I put my indicator on it to see how much runout it has... and as you see, either the shaft is off center in the Die, AKA threads mal-cut, or the threads are off center in the die, and the part is indicating offset.
(Actually I am going to go back out and see if the threads are off-set on the part and snap a Pic. will post in a few)

http://www.youtube.com/watch?v=EKEk-0ZxGF8

Darren:
It's very hard to tell from the pictures, but your die looks like it's not very well made and/or it's well used and worn.

I've never had good results with cheap dies and esp with a material like stainless.
I new decent quality branded die makes all the difference, a real big difference.
You might find that split dies will give you greater control of the thread diameter as they are adjustable.

Darren

sbwhart:
Hi Scot

As Darren said for stainless you need a good quality High Speed Steel Die (HSS) used with a cutting compound one type we use in the UK is RTP, also for lathe work it helps if you've got a die holder that keeps the die central.

I'll post you some photos this afternoon when I get back from my elderly parent duties.  :dremel:

Cheers
 :wave:
Stew

SPiN Racing:
Thanks Guys

Actually that is the ONLY time I used that die.

I took it from the case.. put it in and cut the thread. It looked that shoddy fresh out of the box.

I was gathering the basics.. and it was 19.95USD for a basic tap and die set SAE, and 19.95 for a basic set Metric. SO I got both.
Now I am thinking I regret that.....

Oh and I checked that shaft.. and the threads are dead nuts centered on it. It has NO WOBBLE at ALL. Sorry.. No runout. LOL

The die is mis-drilled I guess.

BUT...

two things I think I may need to do.
1. Buy better Dies. Bite the bullet, and buy the good ones.
2. Make/buy/build a Die Holder that is better than the cheapie cast stuff.

Darren:
Don't buy a whole tap and die set in one go. Apart from costing you a fortune for quality items, you'll prob never use half of them.

Maybe just buy as you need, that way it's easy to get the best available when you need it.

Cheap sets will be carbon steel, for stainless threading these arfe not hard enough and you will be better off with HSS tooling. But again, you really should try the better brands.

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