3" Burrell Traction Engine build.

 Differential Gear Cutting .. Well I thought I'd seen the back of gear cutting, but the differential has a spur gear of 95 teeth.  I bought a new vertex rotary table before Christmas. and also had the dividing attachment to mount on in the position of the handle. With this setup I was able to start cutting half depth teeth, as a tester, so I have an easy job that will keep us busy for a few weeks.  The maths involved for 95 TEETH, using a 19 hole plate and indexing 18 of the 19 holes. This is fairly easy as its simply 1 hole less each time, so keeping track is simpler than other gears. The rotary table has a ratio of 90:1, so 1 full turn would result in 90 teeth so to get the extra 5 teeth is 18/19 of a turn for 95 teeth. <-Photo    Teeth machined to 0.100" depth for first pass to check dividing. And finished Happy Valentines !! Until next month stay safe; make swarf; have fun! Stephen.