Today I worked on a project for my motorcycling friend Neil. He's building two custom 2-stroke bikes (Yamaha RD350 or RZ400, don't recall), and wanted to make new axles out of 316 stainless steel. Nasty stuff!!
He had bought a 23" long piece of 1-3/8" round, I cut it into one 12" and one 11" long pieces. The 11" long one will need a 20mm hole through it, the 12" long one will need a 12mm hole through it. I ordered an extended length 12mm Dormer HSS-Co drill and a similar Precision Twist Drill Co. 23/32" drill from eBay today, should have them later this week. There didn't seem to be any affordable 20mm drills, so a 23/32" is .7812" vs. 20mm at .7874". Close enough. They cost me just under $65 for both.
So today was a good day to put in starting holes with the two extra long Cleveland HSS-Co 3/8" drills I just had resharpened by a friend. (They'd been dulled when Darren & I made parts for his steady rest.) I ran them at 270rpm, which works out to be 26.5sfm. I wanted to keep it at 30sfm or less, so that was a good speed. You could never drill this work-hardening stainless without coolant, so I'm so glad my lathe has that! I didn't measure, but my calibrated eyeball says the holes are concentric to the OD within .010"TIR.
Here's the required photos:
We've already made a pair the solid ones in the center of the print. I can't finish until the drills arrive, plus he's got to edit the larger one for some changes in the big diameter.
He had bought a 23" long piece of 1-3/8" round, I cut it into one 12" and one 11" long pieces. The 11" long one will need a 20mm hole through it, the 12" long one will need a 12mm hole through it. I ordered an extended length 12mm Dormer HSS-Co drill and a similar Precision Twist Drill Co. 23/32" drill from eBay today, should have them later this week. There didn't seem to be any affordable 20mm drills, so a 23/32" is .7812" vs. 20mm at .7874". Close enough. They cost me just under $65 for both.
So today was a good day to put in starting holes with the two extra long Cleveland HSS-Co 3/8" drills I just had resharpened by a friend. (They'd been dulled when Darren & I made parts for his steady rest.) I ran them at 270rpm, which works out to be 26.5sfm. I wanted to keep it at 30sfm or less, so that was a good speed. You could never drill this work-hardening stainless without coolant, so I'm so glad my lathe has that! I didn't measure, but my calibrated eyeball says the holes are concentric to the OD within .010"TIR.
Here's the required photos:
We've already made a pair the solid ones in the center of the print. I can't finish until the drills arrive, plus he's got to edit the larger one for some changes in the big diameter.