Is this Die made improperly?

[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. 

Cheers
 
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.

[sbwhart]

Hi Scot

Here a photo of my home made die holders for the lathe with a variation for holding taps. The small one uses a one peace morse taper and guide made from a blank morse taper baught at trade, the soft end was drilled and tapped and a piece of bar screwed, and the diameter turned for a nice fit in the die holder. You can bore the die holder at each end to take different dies, the larger one just has a piece of bar that you grip in the chuck.



You can buy them from trade but they are good turning exercises to get you to develop your skills and you end up with a usfull tool that will improve your work. 

When I started my apprentiship we spent 12 months in the traing shop under apprentice masters where we made a set of tools, I,ve still got many of my tools there a bit beat up  as I've used them regularly.

Cheers

Stew

[bogstandard]

Spin,

As everyone says, those tap and die sets are no use for anything, you can't even recycle them into anything else. I was given a set of the metric ones, and the only reason I keep them is to show people how bad they really are.

If you search around for a professional tap and die maker, you will find that you can buy very cheaply from them, even cheaper than normal ME suppliers.

A normal smallish sized HSS die is about £9 in the UK, by using a manufacturer, I can buy a HQS (better than HSS) die for £6, and if I buy 5 off, that drops to £2-80p each. Also, you will find that because they supply to industry, they process the order straight away, and you normally get them next day.

In the UK this is who I use. But you are better if you phone or email as the web ordering service doesn't factor in the discount rate.

http://www.tapdie.com/index.html

My die and tapping setup is very similar to Stew's, and I can usually knock up a new die holder in less than an hour.

Where I differ is that I do all my work under power (Ralph was a bit astonished when I showed him the process). As I am normally doing a lot of the same items, and it would take me forever if I did them all by hand.

John

[sbwhart]

I've watched John use a die under power never had the B***s to try it myselve 

Cheers
 
Stew

[rleete]

You can buy them from trade...

I'm sure it's just a matter of terminology, but I'm not sure I understand.  Would this be the same as "buying retail" in the US?

You're just saying make them vs. buy them?

[Divided he ad]

(Ralph was a bit astonished when I showed him the process).

       Very true   


I was.... "but how?... What?..... Why??"  And John was just.... "It's easy look...."   



Nice to have a machine that changes speed quick to aid the process.... Sometimes I think I should have gone for the 'tweekable' DC motor version? .... Ahh well, Mine hasn't held me back much 



Scott,

I know I've already chatted with you over this (haddn't seen the pic's though!!)  but as pretty much said by Darren and Stew.... There is no substitute for a quality tool!  I would have to agree with the buy as you need advise.... I've never needed either a M7 or M9 tap or die yet!!

Admittedly, if your like me you will have to wait a few weeks even months between purchases..... Sadly other bills come first 

Making the holder should be a good topic for you?  (and me.... I can take notes) 




Ralph.

[bogstandard]

Spin,

It has been brought to my attention that you are in fact using the die back to front, but in this situation I don't think it makes any difference. You would still get crap results.
I normally surface grind the back face off, and turn the die around and use that for final finishing to a shoulder.

BTW, there is nothing wrong with well made carbon taps and dies, I prefer them when cutting brass, ali and cast iron (ie softer materials), I find they don't gall as much as an HSS one. But for any harder materials you should always go for HSS and above if possible.


John

[Darren]

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.

In light of Bogs last post I thought I'd better add a bit here as the above wasn't really fair on describing carbon taps.

What I should have said is carbon taps/dies are cheaper to purchase than HSS, I did not mean to imply they are cheap and nasty items per se. And as pointed out they have their slot to fill in our little world.
But for stainless you really want to be looking got HSS or better as john has pointed out.

[bogstandard]

Rleete,

I will answer the question for you. Stew showed you his collection of home made ones, I will show you a few of my bits (machining) to show what he was on about.

The first two pics show my own small tap and die machine holders. This first one shows how I modded a long series tapwrench to fit into a holder that goes into the chuck held in a locked up tailstock. The other tube like one was made to hold very small dies (you can't get a standard sized dieholder for ones this small), you can easily make one to fit standard sized dies. So basically you just turn up an accurate mandrel or hole for them to run on or in. Lubricate the spindles, wack them up to the job and turn them by hand, they should cut nice and true while you turn them into the job. I use them under power, and feel for when it either hits the shoulder or hole bottom and just let go, it then just carries on spinning. Pop the lathe into reverse, hold on, and wind them back out.




This shot shows how they look when ready to go to work.




This shows a commercial set that can do both taps and dies, and is designed to be used under power, but you could use it by turning the chuck. The pin in the slot stops the head rotating, so you have to be very careful when coming to a shoulder or hole bottom. I am just modifying another set that will work on the same principle as the ones above. These will hold up to 16mm taps and dies.



There are lots of types out in the retail shops, and the big one above is designed for production work. With a little bit of thinking, they are very easy to make for only a few bucks, and they will last you a lifetime.

I have also have a lovely, small, auto tapping head for use on the lathe or mill, it just happened to come my way, but I haven't had time to give it a trial yet.

I hope this explains it to you.

John

[rleete]

Thanks for the pics. 

I intend to make those someday - they are on the ever growing list.

[SPiN Racing]

Wow Wow Wow


Lot of information.... starting with me using the Die backwards ROFLMAO.


Ok so.

The dies I have.. are hex shaped.... Rather the metric ones are.

So.. I gather good Dies are not hex shaped.

Next question.....

What keeps the taps from turning inside the holder??

I hate to ask such complete noob questions. But I see how the Hex holds it.


And the long shafts that stay in, and allow the die to thread, while maintaing alignment.. and slide in.. and then free spin.  Nice.

I have done power threading and tapping on the old as hell Lathe at the race shop I work at sometimes.. but it has a big brake lever LOL. SO when close, power goes off, and the hand on the brake to stop it short. A little turn by hand and done.

[bogstandard]

Spin,

Question 1 answer.

Wrong, hex shaped dies are not all bad, just that yours are. You can buy very expensive and very good quality die nuts, they are designed not for cutting threads, but for running down a previously threaded part to clean up any damage, and are usually used with a spanner. Used mainly in places like car workshops to clean up threads that have been damaged.

http://www.tapdie.com/html/dienuts.html

Question 2 answer

If you look at the middle picture of the 3, you will see that there are 3 grub screws around the end of the holder where the die is.
On a standard split die they serve two purposes. The first is to allow for fine adjustment in size of the thread cut, and the second is to hold the die into the holder and stop it rotating.

John

[SPiN Racing]

Ahhh yes.. I didnt see them in the first pic of your die holder. 


Okey.. out I go.. for tonights tinkering.