Have a couple of Citizen C16's in the back of my garage on my own. I'm trying to drill a .065 hole .625 deep in 316 Stainless. No thru coolant. Have checked centerline. I've tried RPM's from 900 to 3150 and feeds from .001 to .002. Used cobalt, carbide, cobalt TiAIN coated. Have went thru about 35 drills so far. The most parts I've ran with one drill is about 10. Any suggestions?
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Drilling 316 Stainless
(5 posts) (4 voices)-
Posted 2 years ago #
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My advice is to slow down to get done faster. Your problem is most likely heat, especially deeper in the hole.
Specifically try about 1750 RPM (30 SFM) and a feed of about .0005 -.0006. Peck like crazy, going only about .005-.010 per peck. Align the coolant as much as you can to go straight down the hole, and make sure it hits the tip of the drill as it exits. Use as high a pressure as you have.
I would use a high quality cobalt drill - one of the ones that costs about 3x what you think it should.
Have had success with this doing hole depths about 10 times diameter, and I don't have thru coolant either.
Good Luck!Posted 2 years ago # -
I'll 2nd the SLOW down on the feed
Also make sure you check your Retract on the peck--How much it stops before cutting again--Factory setting is .02 --we use .005 for the small stuff
TRR.Posted 2 years ago # -
Thanks for the info...
So far have ran 80 parts and just using a standard cobalt straw finish drill. 1750 rpm, .0008 feed, pecking .02, retract out, then back to .005 before. So Far, So Good. Might try a better drill and get more depth per peck out of it.
Posted 2 years ago # -
316 is tricky buis. 316 tends to work harden as the drill begins to cut, so every peck is a potential to loose your edge. if the drill skates on the bottom of the hole, YOUR DEAD! you will need to resharpen. The fewer pecks the better. Keep the the drill cutting edge under the material , if the chip is coming out the top you are OK, Granted this is an act of faith. The best coolant/lub I have found for SS is the old Tap Magic with TriChlor in it, the new stuff is OK.
Slow speed 200-400~ RPMPosted 2 years ago #
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