Posted by Bob N on May 01, 2007 at 14:09:02:
In Reply to: Re: How Do I Make A Pinion gear for lathe chuck posted by mkk on April 27, 2007 at 11:43:57:
The completed pinion was completed. It took about 40 minutes to make the mill jig, about 1-1/2 hours to make the pinion blank and its integral shaft and to cut a keyway for the reference gear (It also included a pilot at the small end of the pinion and threading at the end of the shaft to lock it to the jig.) On of the more challenging items was making a mill cutter and hand grinding to sharpen the two cutting flutes.
Once I had the setup installed on the mill, it took about an hour to cut the 11 teeth.
After it was completed, I installed it in the lathe chuck to test. It was fully functional, but does exhibit a small amount of binding on one small sector of the ring gear, but not enough to be considered problematic. Before I harden the gear, I plan to work it against the ring gear to smooth out the small amount of binding.
I cut the teeth in two steps. First step was with the jig holding the blank so the 15 degree bevel would allow the cutter to gradually cut into the blank (Zero depth at small end, migrated to full tooth depth at large end). I then reset the jig for a 0 degree cant, so that the cutter would give full depth cut of each tooth. This is one area where my expertise fell a bit short. I had ground the cutter contour to exactly match tooth contour. I should have made the cutter a bit smaller than that, because the result was that I got some taper to the teeth which were slightly undersize.
If I were to make it again, I would not have made the full depth cut with the blank at 15 degrees, I would use 8 to 10 and make the cutter contour smaller, which would reduce the tooth taper significantly.
Bottom Line: I now have a fully functional chuck.
Note: I had tried to find the pinion at several places, but replacement parts for this 5 inch chucks are not available.
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