Thanks guys. The handles on the large one are .600" diameter then the knurl brings the OD to about .614" . I milled a 5/8" pocket in one side of the balls and a countersunk hole for a 1/4" -20 socket head cap screw from the opposite side.
The ball turning attachment I made for my old lathe still needs some work to be used with the new machine, I may make a new base or just an adapter. I have about 10 more of these 3/4 inch bearing balls so this was a way to use some of them. My best effort at annealing them got them just soft enough to work on with HSS drill bits. I guessed at the optimal temperature by color, medium bright red hot and I think that was OK but I think I let them cool too fast. For cooling I put about a cup and a half of sand in a tin can and heated it to 400 degree in my shop toaster oven. Then I dropped the red hot balls in half of the sand and buried them with the other half. I reduced the temperatue in the oven over a period of an hour and turned it off and they then cooled in the sand for another hour before I handled them.
I have annealed ball bearings in the past with a method I was taught by an electric motor rebuild shop owner I worked for when I was a kid. He would set a bunch of bearings on bricks and then set up a bonfire with cut up pallet lumber over the bricks. He would get the fire going and maintain the temp of the bearings by color for hours, usually at night with plenty of Hungarian wine to keep him company. After the bearings were completely covered by the hot coals he would usually pass out from too much wine and the fire would burn itself out. A good fire would leave nothing but ash after it went out and the bearings would still be warm when I got to work at 8 AM the next morning. The bearing were soft enough that I would be able to cut the races off with a hacksaw. The old guy barely spoke english but I learned a lot from him, including how to sweat out a Hungarian wine hangover with a hard day of work. He was an artist with all things metal and used the balls for all kinds of projects. To this day I can't make myself throw away a large ball bearing and I have used George's method in a summer campfire a couple of times.
