Parting brass tube

[fatal-exception]

Ok, here's a problem that I've never seemed to be able to find the solution to.

I have to make about 100 thin brass washers (3/8" OD, .305 ID, .025" Long). I have the tube that I need to make them, but the same old problem arises, how to part them on the lathe so that I don't need to do any deburing.

Is there some special trick about grinding the parting tool that will create a burr-less part? Generally, I would use a thinner than normal parting tool for this type of job, maybe the thickness of a hacksaw blade, ground to the regular geometry of a parting tool. What I end up with is a small ring on the parted off pieces that is a pain to remove with a xacto knife.

Can anyone shed some light on this for me?

Thanks,
Paul

[Geof]

It is impossible to get a part off completely burr-less but you can come close.

Use a HSS tool and grind the cutting face at an angle so it has a sharp pont that breaks through first on the side of the piece being parted off; this will leave a minimum burr.

If you are doing this on a CNC and want to fiddle around a bit grind a vee grooving tool to cut a vee in the ID so that the parting tool breaks into the vee and leaves even less of a burr.

[fatal-exception]

Thanks Geof, I will give that a try.

Paul

[CalG]

If you start with stock that needs the bore cleaned up, less burr is generated if the parts are dropped during the boring operation than when the parting tool is plunged through the ID.

Plus, the parts drop on to the boring bar and not into the chip tray ;-)

CalG

[HuFlungDung]

If I might add, resist the impulse to give any hook or positive rake to the top of the blade. It should be neutral or slightly negative for brass and bronze, and very sharp. This will produce a ring that may come off with the part but will harmlessly pop off when you give it a squeeze with needle nose pliers. It may also help to allow the tool to dwell exactly at the ID diameter, just at the moment before the piece comes off. This will give it a little bit of a chance to fatigue the metal still joining the part to the stock, and help make a cleaner pop off. If your tool has any hook or positive rake, it will pop the piece off before this has a chance to occur.