[icecats]

I have the Tormach PCNC 770 mill and this tooling setup. I need to hold a 1/2" hex shaft (which I don't have yet) in the spindle. How could I do this. If I understand correctly, 1/2" hex is actually a bit bigger than 1/2" on the diagonal. Would the shaft fit in a 1/2" spindle?
Thanks

[SCzEngrgGroup]

Get a 1/2" Hex R8 collet.

Regards,
Ray L.

[icecats]

Get a 1/2" Hex R8 collet.

I have not been able to find one of these. Do you have a source?

[Jim Dawson]

A 1/2 inch hex is 0.5774 across the points.

That is a very uncommon collet, but I actually found them. https://www.aliexpress.com/item/Hot-...8.4.104.mvAXAj

Depending on what you are doing, a drill chuck may work also, but they don't like to be side loaded much.

[GITERDUN]

I have not been able to find one of these. Do you have a source?

This is probably your best option- will hold a lot of hex and round parts.
Z LIVE CENTER 3" 3 Jaw Precision Lathe Chuck with R8 Shank (Non-Rotating) | eBay

[icecats]

I found this 5C Hex Collet on Tormach's website. How could I use this with my current setup?

[Jim Dawson]

I found this 5C Hex Collet on Tormach's website. How could I use this with my current setup?

Unless they make a 5C collet holder that will mate to your spindle, I don't see how a 5C collet would work. A 5C collet is about 1.25 on the OD. We are assuming here that your spindle is a R8, that is the case, correct?

[popspipes]

Hardinge makes an R8 hex in decimal sizes, kind of pricey though, and an 18 day wait as they are out of stock.

https://www.shophardinge.com/product...17570028000000

[icecats]

I am leaning towards purchasing a 5/8" or 3/4" inch chuck with a jacob's taper. The hex should fit in here.

[GLCarlson]

Hex stock half inch across flats is around 0.56 point to point.

Two options: turn it round for a half inch or so and hold with your ER collets. That does assume you've got a lathe.

Or buy some tooling. A small 3-jaw chuck with an R8 backplate may be your best option. R8 hex collets aren't obviously available, and -depending on what you're doing- holding either tooling OR a workpiece in a bigger drill chuck could be exciting if the drill chuck is mounted on a taper arbor (that is, held by friction only) - drill chucks are a really bad way to hold milling cutters because the side forces can work the whole assembly loose during a cut.

Or, wild idea, make a 5C collet holder for your spindle TTS spindle. 5C is readily available with hex, round, square shapes, and not outrageously expensive. Remember, you don't have to tighten the collet from the rear: a compression nut over the front will work as well and would easily pass the half hex stock. Problem with an approach like this is that it's at least a 2 1/2-3 inches long and could be a bit wobbly depending on design. But with a little work, you could probably make it all with just the Tormach; don't necessarily need a lathe. That might actually be a rather slick piece of kit to have for those oddball situations where the more conventional holders just don't work due to shape or diameter.

[IMT]

Depending on the concentricity required, you could take a 1/2" TTS set screw holder and mill a 1/2" hex into it. Make sure one set of flats are perpendicular to the set screw hole.

[Steve Seebold]

Why don't you machine a hex into some aluminum soft jaws. If you need help making the program, send me a sketch of what you're trying to do and I'll do it for ya. It's really easy to machine a hexagonal pocket in aluminum jaws.

[IMT]

Why don't you machine a hex into some aluminum soft jaws. If you need help making the program, send me a sketch of what you're trying to do and I'll do it for ya. It's really easy to machine a hexagonal pocket in aluminum jaws.

How would that allow him to hold the hex in the spindle?

[icecats]

Why don't you machine a hex into some aluminum soft jaws. If you need help making the program, send me a sketch of what you're trying to do and I'll do it for ya. It's really easy to machine a hexagonal pocket in aluminum jaws.

Do you mean soft jaws that fit with some form of Tormach tooling?
Thanks

[Jim Dawson]

You could make a split adapter to fit your R-8 collet.

What is your end goal here, is it to ''turn'' the hex as in a lathe?

[icecats]

You could make a split adapter to fit your R-8 collet.

What is your end goal here, is it to ''turn'' the hex as in a lathe?

Yes, that is what I would like to do. What do you mean by split adapter?

[Jim Dawson]

You make a round plug that fits your collet, put a hex hole in it, then saw it in half so it will squeeze onto the hex then the collet is tightened.

[SCzEngrgGroup]

How would that allow him to hold the hex in the spindle?

That's easy! Just weld an R8 shank to the vise!

Regards,
Ray L.

[Jim Dawson]

That's easy! Just weld an R8 shank to the vise!

Regards,
Ray L.

:cheers:

[icecats]

You make a round plug that fits your collet, put a hex hole in it, then saw it in half so it will squeeze onto the hex then the collet is tightened.

Can this be done without a lathe?