Well, I've never had this happen to me previously on 303, only on 304. Guess I haven't really lived...
I have a 303 part in the lathe that needs a precision shaft bore for a gearmotor shaft, and it looks to me like it work-hardened when I was drilling it out (I guess). I've been trying to get a carbide-insert boring bar to bite into into it, and I am seeing serious bell-mouthing, almost out to my .750 finished bore size. The bore is 1.25" long. The hard part is in the middle and back of the part, and I just thought I would canvass here to see what options there are. Things I have considered:
-- Grinding the zone out, but no tool post grinder. Have to use a Dremel, unfortunately. No idea how deep the hardened layer is (anyone?)
-- Making the part again. (lousy option)
-- Carbide reamer (also lousy $$$, and might get jammed in the hard part and then it's back to re-making the part)
-- Bore larger and sleeve, presents some complication with finishing the part.
-- Some magic suggestion from someone that works immediately and perfectly.(My favorite)
This is a single part, which is why I'd like to save it. I have a second mating part as well, that is 2+" long with same operation, and then I need to broach a keyway in both.
I have a 303 part in the lathe that needs a precision shaft bore for a gearmotor shaft, and it looks to me like it work-hardened when I was drilling it out (I guess). I've been trying to get a carbide-insert boring bar to bite into into it, and I am seeing serious bell-mouthing, almost out to my .750 finished bore size. The bore is 1.25" long. The hard part is in the middle and back of the part, and I just thought I would canvass here to see what options there are. Things I have considered:
-- Grinding the zone out, but no tool post grinder. Have to use a Dremel, unfortunately. No idea how deep the hardened layer is (anyone?)
-- Making the part again. (lousy option)
-- Carbide reamer (also lousy $$$, and might get jammed in the hard part and then it's back to re-making the part)
-- Bore larger and sleeve, presents some complication with finishing the part.
-- Some magic suggestion from someone that works immediately and perfectly.(My favorite)
This is a single part, which is why I'd like to save it. I have a second mating part as well, that is 2+" long with same operation, and then I need to broach a keyway in both.