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View Full Version : Cutting multiple O-ring gooves with a lathe



Uman
09-21-2003, 06:58 PM
I am trying to develop a production technique to consider production of a plastic cylinder fitting for my new invention. The cylinder ID is to have four O-ring grooves cut and equally spaced on the cylinder ID circumference at equal depth.

Is it possible to make a special tool that will cut all four O-ring grooves simultaneously on a lathe? I envisioned a bar with four cutters spaced along the bar at 90ْ of the centerline. The cuter tips will be ground to the shape of the individual grooves.
Does this seem possible or should I not waste my time making this special tool?
If four grooves is too optimistic, how about only two at a time?

Material: Delrin or Polyproplene plastic
Cylinder OD: 1.75
Cylinder ID: 1.25
Cylinder Length 6”

Thanks for any suggestions
Cheers,

Alistair Hosie
09-21-2003, 07:15 PM
I cannot see why this should be so difficult there are such devices for cutting wood for decorative purposes .Not exactly the same I agree but if the tool is well made and applied at the right angle I.E face on with equal pressure should be okay as I see it.But then again I'm no expert.I would have thought a single tool with equally spaced points cut into it would suffice for cutting plastic,instead of having to fit four individual cutters.I have cut plastic bushes by hand on a wood lathe,and that stuff cuts and turns beautifully.Alistair

Thrud
09-21-2003, 08:02 PM
Uman:
There is no reason you cannot do this. I would try to incorporate "top notch" sytle inserts in a 3/4"-1" boring bar. These are easily replace and will allow great sonsistancy to your work piece in a production setting. You could also make use of HSS or brazed carbide blanks clmped on bar. If you do this I would suggest amking a grinding jig to insure consistancy on the bits. Use High pressure air to help blow the "fuzzies" out and keep the tools cool to prevent melting the plastic.

Take my word for it, in production things like "consistancy" mean a lot in the long run.

[This message has been edited by Thrud (edited 09-21-2003).]

Doc Nickel
09-21-2003, 10:03 PM
Well, it seems it'll take some brainpower, but if you could find a carbide face-grooving insert (seems to me I've seen such a thing) the proper finished ring width, you could make a square tool to hold them.

Have each insert bolt to a different face of the square, and have each seat machined to the proper depth. Then it should be a matter of centering the tool to the work, and plunging it in. All four cut simultaneously- each blade faces in the proper direction.

Delrin is pretty forgiving- make the tools sharp and aligned properly, turn it fast and punch 'em in and pop 'em out as quick as you can to prevent heat buildup.

Doc.