- Joined
- Aug 23, 2014
- Messages
- 932
Since I have a 1.5mm lead screw on my minilathe I decided I could use a 63 tooth change gear to help make imperial threads a bit more accurate. I had an 80 tooth gear that was damaged so I thought I'd use it as my first victim. I cut it down to 65mm O.D. after mounting it on an expanding arbor. I turned the arbor down for a press fit in the gear, then tightened the expanding screw and cut 1/2-13 threads on it and secured the gear with a large washer and nut to prevent any movement. The minilathe uses Module 1, 20° P.A. gears. I used an LMS 4" 72 to 1 ratio rotary table with a 28 hole index plate, 1 turn plus 4 holes for indexing. Tooth total depth was 2.4mm according to the math and checked out against the original change gears. I had to kind of mickey mouse mounting the rotary table since the minimill doesn't have enough Y axis travel to mount the table on center. I used a #7 gear cutter (55-134 teeth) and matching arbor. The shavings are powder like cast iron. It went smooth with no hiccups. The new gear matches up and runs true. It only took me 70 years on this earth to make my first gear. I guess you could say I'm a slow learner. It took about 4 hours to do everything including math and installing the index plate setup.
Roy
Roy
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