View Full Version : Chip Breaker Questions !!!!!!

06-10-2010, 11:27 AM
I'm wondering if anyone has any solutions to chipbreaking with TPG style inserts. I get the best results with the TPG style inserts with a dead sharp edge. However since they are a flat insert with no chip breaker geometry I get streams of turnings. It's not a real problem on small jobs but on any internal turning it bird nests inside and depending on the depth of the bore I always have to stop and clean out the hole. I've tried mechanical chip breakers that clamp down over the carbide insert but it makes no difference, I just don't get chips unless I'm turning cast or brass. Coolant might help as it would cool the turnings and maybe allow them to harden, becom brittle and break but I don't use coolant.
Any ideas ????


06-10-2010, 11:45 AM
I don't know of any good solution other than changing over to a different style insert that has chip breaking relief. I don't know of any TPG style that has chip breaking. The cost of the new tooling is alot less than a lost finger......

Mike Burdick
06-10-2010, 12:47 PM
You might try making a chip breaker that fits over the insert and can clamp to the tool handle or some convenient spot. Have you tried adjusting the feed and/or speed when you're turning? Sometimes that helps.

06-10-2010, 01:00 PM
joelee: You may need to fine tune the clamp on breakers to be very close to the edge, you likey take shallower cuts on internal holes so that makes chipbreaking much harder. generaly its deep cuts with high feed rates that make chipbreaking in stringy materials possable.

Also, have you tryed mounting a shop vacuum? Sometimes you can manage to just get the strings to continiously vacuum up, especialy on through bores.

06-10-2010, 02:07 PM
Edit: Reread of OP makes my post irrelevant.

06-10-2010, 02:23 PM
I will sometimes grind a chipbreaking groove behind the cutting edge on brazed carbide tool bits, if needed with a green wheel or a small diamond blade. I don't see why you wouldn't be able to do that on an insert with a little effort.

06-10-2010, 03:28 PM
Jack up the feed and speed.

A chip breaker style insert will help too, but mostly give it more speed.

If you're on a small, slowish, low power machine this can be a problem.

06-10-2010, 04:24 PM
I've tried just about all of the above mentioned ideas. Tried the mechanical chip breaker and all that did was kind of redirect the stream flow, didn't make chips. I found a TPG type insert with a slight chip breaker groove all around it but that type TPG insert has a honed edge and doesn't cut as well as the dead sharp TPG. I did have some real good luck with the CNMG style insert which has a negative rake but that style is somewhat restricting. VNMG and DNMG works well also but have some of the restriction problems that the CNMG has.