Flycutting Stainless steel

I would use a hole saw and plenty of cutting oil to do this job.

I had to cut some holes like this in some 3/8 stainless plate. Even drilling this stuff is a pain. I originally tried using a boring head and carbide tipped boring bar, but even the lowest speed on my mill/drill just destroyed the carbide once the hole got near 2". Finally I clamped it to a rotary table, chucked up a 3/4" roughing end mill, and hogged out the hole with the rotary table. I used the lowest spindle speed available, 120 rpm, and lots of feed rate and smoky sulfured cutting oil. Hot, sharp, evil swarf.

Later on the same job I snapped off a 6/32 tap and had to grind it out with a dremel.

Nasty job all around.

Al

Thanks to all for good advice. If I had some spare pieces I might still be tempted to see what I can learn (break) Judging from the answers I am farming this one to the pros.

Regards,

Boris Mohar

Got Knock? - see: Viatrack Printed Circuit Designs

FWIW, I use mild steel flanges on stainless headers. I think I got the tip from the Burns webpage. I'd job this out if I didn't have a drill press/mill capable of 50 - 75 rpm to use a hole saw. Your trepanning tool won't work, at least I couldn't make one work (I tried the same thing in mild steel once).

Brian

Since those are the tools you have, I would give it a shot. I would probably drill a hole for the center drill to fit in first and substitute a solid rod in place of the drill. Then build a dam around the location with some wax or something. Might also plug the center hole with the same stuff. Add oil and try it on the lowest speed. Try to feed so that you get a continuous chip about .005 thick coming off. Just don't let it rub without cutting. You will probably have to stop and resharpen the cutter several times per hole if it works at all.

Let us know what happens.

Dan

I will get a scrap piece first and practice.

Regards,

Boris Mohar

Got Knock? - see: Viatrack Printed Circuit Designs

I forgot to add that Stainless cuts better with somewhat more relief and rake than ordinary steel.

Dan