Dividing Head / Rotary Table

The final one I made has 40 teeth so it will have the desired 40:1 ratio. Hobbing a gear is tricky - even if the gear diameter is correct, it doesn't take much for the teeth to wander initially in the process, resulting in 39 or 41 teeth when you are shooting for 40. A more pronounced (and controllable) gashing operation will prevent that.
 
Good job , enjoying your progress every time you try new things your learning and becoming more proficient and confident. There will be no stopping your desire to build more tooling and even machines. Good luck thanks for sharing.
 
Nice job on the hob and the worm and worm gear! You are correct, parting when the part is trapped by a center is not a good idea!
I recently had to part off a 1/2" piece from a 2" diameter piece of steel which I was forced to support with a center (too big to fit through the chuck and too short to use the steady rest). I discovered another use for the spindle crank I recently made for my South Bend 10L: I parted it off normally until I got close and then installed the handle and finished off turning it by hand. It worked fine (but slowly) and I was able to stop instantly when it finished the cut!
 
Parting off with a center in the work is not a good idea, it will pinch the work to the tool and cause big trouble. You could get away with it at the beginning, but not at the end of the cut.
 
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