Technical Machinist help

I need some info/help with understanding collets and specialty collets. If I knew what the descriptions meant I could probably figure out what to order but I’m lost.

I’m trying to fabricate/adapt a square tool holder onto my reciprocal machine. Like a pull max.







I see these things -


But I don’t know what to get, or if they work together. With the other square holders I see.

Need some help please

 

If you were looking for collets for a Bridgeport mill you’d want R8’s for example. Judging from the appearance of what your pictures show I think those are ER’s. The key word there is I “think”.
Look up ER style collets and see if there is a manufacturer that offers collets for square tools.

 

Not exactly what you have but getting close. https://www.mcmaster.com/products/square-collets

 

Pullmax collet.

 

I think the thing you will find is that when you do get something that will hold square shapes in position, they will probably not grip tight enough to resist a "pounding" application of force vertical to the axis of the collet. They position it fine and have a fair amount of grip but may not prevent downward movement of the part when applying continual or repetitive force. A positive stop below the part may be needed to prevent movement.

An alternative you might consider is getting a 4 jaw chuck and modify it for your needs. It will do any size square or rectangle but it won't be self centering. Thats actually good because it would allow you to adjust location slightly when needed. Most of what it appears you will be doing could be located visually. Its a "one size fits all" solution and will hold round, square, rectangular and oval shapes. It would still need a positive stop added to its bottom side. That should be easy to do

 

You can get a 5c square collet but as someone gas said it may not take impact

 

Does that Collett go to the type of holder I pictured above ?

 

There wound be solid blocking and substantial iron backing up the bottom of the bottom die/tooling.

 

If it were only that easy.
Of course I tried that and thinking it couldn’t be easier. I found a lot of not what I want nor helpful information nor pictures of what’s under the spanner nut.

 

The holder you show is an ER32 style holder . A 5c holder is different , the collet is tightened from the back.

 

Collet wont take that kind of beating.
This is a large weld-a-hub for a square shaft.
Find the appropriate size you need for your tooling and modify accordingly. Then you have something solid to pound on.

 

So Im looking for a ER 32 square collet?

 

that might be what this guy made up ?
I’d fab up a substantial solid base for the vertical pounding forces to the bottom of the die shaft, am I correct in thinking that the collet will control the lateral movement?


It’s kind of a mystery what’s under the spanner nut, but this is the Pullman lower tool holders.
Not easy to come by without the machine.

 

Maybe. The concern I have is the length of the bottom support. Unless it has to be long, I would want it shorter than whats in the picture. There isn't anyway to know for sure without trying it, but shorter gives less room for it to move any.

 

Show some pics of what you have with your nut off.
The ER that is. Could it be just holding a square shoulder adapter tight. Think flanged bushing.
No collet involved what so ever??
In therory a collet would work if you had a positive stop to take the beating and the collet would just be there for location/quick change.
Look at 5c collet blocks with stops for ideas.

 

I don’t have anything to show

 

https://www.baileigh.com/7-8-square-tool-holder-for-power-hammer

 

5c collets are pinned to keep them from rotating.
Most have a nut on the back, but could use one on the front(top in this case.)
So you could make it work as long as you arent relying on the collet for the pounding force. Hense the stop for the bottom of the tooling.

 

Are you still looking for a picture of the collet?

 

Sure

 

This is the lower of a P5 which used 19mm or .750" shanks.
The collet has an included angle of 25* and is .867" tall. The major diameter is 1.601". I think the key is the 25* taper which is a releasing taper so there is no resistance in changing tools. The highth screw is about 1.25" on diameter and the threaded base piece is oriented and locked in place with two small dowel pins. It is .687" tall, all threads which are 1.785" in diameter and is the only part that has the square hole in it. The collet is soft, I touched it with a file, and has the 4 slots from the top, and eight from the bottom.
Let me know if I missed something.

 

certainly look same as mill collets!

 

ER collets are only available for holding round items; they are intended to hold tooling like milling cutters etc. You could make the 5C collets work if it isn't possible to get hold of the proper tooling. square and hexagonal 5C collet blocks are available, here's one on UK ebay https://www.ebay.co.uk/itm/37323048...o0ceCoaaspFAysAZbH-YSVNOTRa8pq0BoC5sgQAvD_BwE a similar/the same thing is almost sure to be available in the USA as the C in 5C comes from Cataract, a company owned by Hardinge who invented these widely used collets. As well as the external thread used for closing the collet, 5C collets also have a 20 TPI internal thread in the rear, this is there to fit a 'collet stop' which you'd use for repetitive work on same length items e.g. slotting screw or bolt heads. If the rear of the collet stop was against the machine base it would take all the vertical forces; the collet and collet block would only be providing lateral support.