I never seem to get as much done as I hope, which is a recurring theme in my life. This weekend's work on the Dingley followed suit.
I had drilled and reamed all of the holes in the black stock deep enough to allow for FOUR gear blanks, it turns out! In this picture, I'm using the shop's little WWII-era Sheldon lathe to cut grooves in the stock down to the depth of the gear teeth. By doing this, I eliminate a great deal of tool pressure on the custom ground milling cutter. I don't want to risk breaking that as it's the only one I have! Notice the double groove between the first and second blanks? That allows me to make a full depth cut through the first blank without touching the second one. If things go wrong, it should be easily seen in the first blank and can be corrected before going on to the other three:
Once turned, I proceeded to the vertical mill and futzed around with an indexing head, which allows me to advance the stock 12.85 degrees per cut. This will accurately space the 28 teeth on our gears. I burned up a lot of time getting this arrangement set up to suit me, but hurrying at the stage can easily land a fellow back at the starting point. Here you can see the teeth within about .020" of finish depth:
As this operation progressed, I grew so focused on the task at hand that I forgot to take pictures! I finished cutting the gear teeth and then went back to the lathe. I carefully parted all four gear blanks off of the piece of bar stock and proceeded to stone one side to check flatness. Being acceptably so, I relaxed and moved to the surface grinder to really flatten things out. Remembering the camera, I managed to get this pic. It's blurry, but almost everything in the field of view is moving:
The hardening process works much better if the parts are brought to a high polish beforehand. After grinding, I rough lapped the blanks to ensure flatness and get them one step closer to final polish:
The teeth have yet to be deburred in this photo. Although a tedious job to individually deburr all of them, it's vital and I can do it as spare time crops up during the coming week. After a few secondary machining operations, we'll be ready to heat treat.