bostonmick Posted April 15, 2018 Report Share Posted April 15, 2018 If you know anyone who has a rota broach try that plenty of fluid and take your time. I have drilled loads of stainless this way and the size you want in one hit Quote Link to comment Share on other sites More sharing options...
victorismyhero Posted April 15, 2018 Report Share Posted April 15, 2018 slow speed and buckets of pressure Quote Link to comment Share on other sites More sharing options...
Dougy Posted April 16, 2018 Report Share Posted April 16, 2018 If your still struggling let me know. I'll shoot a hole through it anywhere you want. Quote Link to comment Share on other sites More sharing options...
Seadog1408 Posted April 16, 2018 Report Share Posted April 16, 2018 Just cut a 10mm by 75mm deep hole in a 316 grade SS bar for the bore of a signal gun, used a cobalt bit and some cutting fluid, did the trip nicely. Quote Link to comment Share on other sites More sharing options...
Paul223 Posted April 16, 2018 Report Share Posted April 16, 2018 I’d plumb straight for an 11mm cobalt, alter the pillar drill gearing for slow speed and use plenty of cutting fluid. Center pop the work first ! Quote Link to comment Share on other sites More sharing options...
pycoed Posted April 17, 2018 Report Share Posted April 17, 2018 HSS is fine, but the killer with stainless is work hardening. Never let the bit skid on the work or you'll harden the S/S & burn the drill in a moment. You MUST use plenty of down pressure to make sure the bit actually cuts. Do that & any good (SKF/ Dormer etc) properly sharp HSS drill will do the job fine for a few holes. Use a pilot just larger than the web of the drill (around 4mm for a 11mm drill). (Did I mention keep up the downpressure?!) Production would be a different matter. Quote Link to comment Share on other sites More sharing options...
activeviii Posted April 22, 2018 Report Share Posted April 22, 2018 On 4/16/2018 at 14:35, Dougy said: If your still struggling let me know. I'll shoot a hole through it anywhere you want. Almost! Quote Link to comment Share on other sites More sharing options...
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