Drilling 316 Stainless Steel

[ianjParticipant @ians]

Hello All.

I have a project using 316 Stainless steel flat bar 8mm X 30mm which calls for 9mm holes to be drilled and counter bored 12mm diameter by 6mm deep. I have solid carbide 9mm drill and 12mm endmill for the counter bore. I’m aware that stainless steel can be difficult to machine and work harden. I’ve tried Google but most advice is CNC related.

I’m asking :

1, Should I pilot drill for the 9mm hole ?

2, What RPM for the 9mm hole and 12mm counter bore?

I will be using my Tom Senior milling machine,

Thank You

Ian

[bernard towersParticipant @bernardtowers37738]

Definitely drill in steps and slow speed with good cutting oil(rocol) and no real need for carbide drills. Been doing the same thing myself today and machining 316 with HSS, just keep the speed down.

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