Rectangular Bar Stock in CNC Lathe

pebbert9 · May 4, 2019

We machine a lot of rectangular brass. Typically we cut the brass to length and then use fixtures to hold them in the CNC mill.

I was thinking we could move to a CNC lathe with live tooling and cut out the cutting and fixturing by feeding bar stock.

Is there a good way to hold rectangular bar stock in a CNC lathe in sizes around 0.75" x 1.00" or 1" x 2"?

bigjon61 · May 4, 2019

S-style collet pads and collet chuck. Buy a set of 2" square and a set of 1" square collet pads and you can mix and match. Coupled with the right size spindle liner it should work really well.

Limy Sami · May 4, 2019

Measure across the diagonals and bore a set of soft jaws that are wide enough to catch all 4 corners.

Or Bore a flanged split sleeve to across corners dim (which can be bolted to a soft jaw face if desired) and put in a couple of radial set screws so the stock can only go in one way.

Etc etc etc

Delw · May 4, 2019

pebbert9 said:
We machine a lot of rectangular brass. Typically we cut the brass to length and then use fixtures to hold them in the CNC mill.

I was thinking we could move to a CNC lathe with live tooling and cut out the cutting and fixturing by feeding bar stock.

Is there a good way to hold rectangular bar stock in a CNC lathe in sizes around 0.75" x 1.00" or 1" x 2"?

the 3/4 x 1" is avail in a 16c collet from hardinge I am sure the other sizes or both are avail in bigger collets and pads.
the only problem you will have with long stock is the liners and bar feed beating up the edges of the stock.

Orange Vise · May 5, 2019

A Royal Quick-Grip or Hardinge Flex-C collet chuck with wire-EDM'd collets should do the trick. You'll need one of these larger collet chucks for the 1x2.

As for spindle liners, Trusty Cook makes urethane liners to spec and shape.

Ox · May 5, 2019

pebbert9 said:
We machine a lot of rectangular brass. Typically we cut the brass to length and then use fixtures to hold them in the CNC mill.

I was thinking we could move to a CNC lathe with live tooling and cut out the cutting and fixturing by feeding bar stock.

Is there a good way to hold rectangular bar stock in a CNC lathe in sizes around 0.75" x 1.00" or 1" x 2"?

This is dooable in S26's as they have 4 splits.
I use a similar method of mixing rounds to throw a bar out of center a bit too.

If you get into S30's tho, I think those have 6 splits? If so - you would need custom pads.

This wouldn't be too bad at all unless you are trying to put a magazine loader on it as well.
If so - the challenge would be that the bar wouldn't drop the same every time.

Also - Hardinge will make any shape in any collet to your spec if you want a solid collet, or custom pads.
I have several custom shaped collets around here.

-------------------

Think Snow Eh!
Ox

Mud · May 5, 2019

Ox said:
Also - Hardinge will make any shape in any collet to your spec if you want a solid collet, or custom pads.
I have several custom shaped collets around here.

-------------------

Think Snow Eh!
Ox

I have a few custom W&S style custom collet pads here, one set is for a largish rectangular bar in #5 W&S size. The rectangle is offset in the long direction, they were used in a turning center to make brass fittings. IIRC the name on them is Hardinge.

Darren Janecky · May 10, 2019

Delw said:
the only problem you will have with long stock is the liners and bar feed beating up the edges of the stock.

Nah, you just make a plastic ring with the rectangle hole through it to slide tightly over the bar end and use a liner for the size of the ring OD.

pcasanova · May 13, 2019

spindle liner

here's a liner we had trusty cook make for us. Also LNS has a kit for
square/irregular shaped stock that helps align the stock on the bar loader.

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Rectangular Bar Stock in CNC Lathe

pebbert9

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bigjon61

Hot Rolled

Limy Sami

Diamond

Delw

Stainless

Orange Vise

Titanium

Ox

Diamond

Mud

Diamond

Darren Janecky

Plastic

pcasanova

Hot Rolled

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