[Medmach]

We are currently working on a new project, drilling .051"-.056" diameter hole through a 1.400" long shaft in our Citizen M32 swiss lathe. The material is Alloy 20, the drills are Mitsubishi carbide(I forget the exact style). We have had limited success with the drilling, chipped tools poor finish (i should mention the finish requirement of 63 microinches) etc, with tool life being the biggest challenge.

We have subcontracted gun drilling, but due to cost and added complications to the remaining machining operations, this is not ideal.

Any sugestions or recommendations are appreciated.

Chet Pierce

[underthetire]

Used to turn a lot of nickel alloys. Tool life is always bad. Found the old kennametal k68 carbide was better than most. We used sumitomo new point drills (sharp edge, not honed edge) and could only get 10 parts per drill, even with HPC. The alloys we turned were tough though, nickel with titanium and a few other nasties.

[mactec54]

Medmach

If it is not being used in chloride solutions, which alloy 20 is good for, then go with 416ss this is very good to machine