Howdy again, feller metal reckers.
I have some 1/4-inch 316 SS thru-the-wall bulkhead tube fittings that I need to a 17/64 hole straight thru - just large enough for a 1/4-inch OD tube to slip thru without binding. The stop has a .18-inch ID, so I started from the tube end with a 3/16 cobalt bit, then increased the size gradually until I got 1/4-inch all the way thru with little trouble, taking it slow.
I then put the 17/64 bit in (same cobalt, mfr, point, etc) and it drilled fine starting at the tube end. But when it gets to the thick wall MPT end, it stops and I can't get it any further. I also trying going at it from the MPT end and won't penetrate at all.
There's a good chance I heat hardened the fitting by letting it spin - the tip glowed orange before I realized what was going on.
Anyway, that's where I am. Any suggestions from the stainless folks?
As a last resort I can enlarge it with a round rat tail file, but would rathe have a nice smooth round surface.
I'm using Swagelok but could not find that fitting on their website. Good products, but website is nothing like McMaster:
Photo of the same type of fitting, different make - 1/4 tube x 1/4 male:9546388
Snuffy Sniffs (No relation)
PS -- Larry? Pay attention and yew mite git some smarts.