Back up ring skive cut on lathe?

[Ez_DuzIt123]

This may be a dumb quesiton but does anyone know of a good way to make backup rings on a lathe? Currently we are turning the od and id then taking an .015 endmill to create the skive cut on the ring. It takes a little while and there is a lot of deburring that needs to be done afterwards. My first plan was to create some sort of pneumatic fixture with a razor blade attachment and after the ring is turned on the lathe you put it in the fixture and the razor blade cuts the 22 degree gap in the ring. Then i started thinking maybe there is a way to do this complete in the lathe? Anyone have any thoughts or suggestions? I'll attach a part of the drawing sent by the customer so you all can get an idea of what i am talking about. The rings are made from PEEK.

 

[TeachMePlease]

Leave a couple thou on the OD and the ID, cut your slot, then finish turn both, should eliminate most of your deburring.

 

[BoxcarPete]

If it were teflon, I might say you have a chance at plunging a blade in at a 22° angle and then peeling the whole thing off at once, but that's PEEK, and it's pretty stout for a backup. You can try that, but I think you're more likely to get scrap than a usable part.

Might be worth a shot though if you are daring.

 

[4GSR]

We used to use a jewelers coping saw to scarf cut backup rings with.

Most of the seal companies today scarf cut them with some kind of sharp knife, in a guillotine setup. Also seen setups where they use a .010-.015" slitting saw to cut the scarf with. PEEK is not easy to cut with a knife like Teflon is but is doable.

Ken

 

[Ez_DuzIt123]

We used to use a jewelers coping saw to scarf cut backup rings with.

Most of the seal companies today scarf cut them with some kind of sharp knife, in a guillotine setup. Also seen setups where they use a .010-.015" slitting saw to cut the scarf with. PEEK is not easy to cut with a knife like Teflon is but is doable.

Ken

Jewelers saw on an angled live tool I am assuming? Do you just cut a helix around the entire rod then bore the ID to finish the part?

 

[NC Rick]

I make them in small quantities, a hundred or two at a time. We use 5-600 a year. I’m buying the filled Teflon molded and skived to my specifications and then use a small jig which I push the band through, toggle clamp in place and then cut it with a little sharp shear type die that has a 90 degree step so they are “z” cut.

 

[DDoug]

This may be a dumb quesiton but does anyone know of a good way to make backup rings on a lathe? Currently we are turning the od and id then taking an .015 endmill to create the skive cut on the ring. It takes a little while and there is a lot of deburring that needs to be done afterwards. My first plan was to create some sort of pneumatic fixture with a razor blade attachment and after the ring is turned on the lathe you put it in the fixture and the razor blade cuts the 22 degree gap in the ring. Then i started thinking maybe there is a way to do this complete in the lathe? Anyone have any thoughts or suggestions? I'll attach a part of the drawing sent by the customer so you all can get an idea of what i am talking about. The rings are made from PEEK.

View attachment 272949

Are you allowed to heat the knife (if you went with that method).

I could see a disposable razor (for repeatability) mounted on a block
with a watlow heating cartridge in the block.

 

[Ez_DuzIt123]

Are you allowed to heat the knife (if you went with that method).

I could see a disposable razor (for repeatability) mounted on a block
with a watlow heating cartridge in the block.

PEEK has a very high melting point. I don't think this would work