Hi all I,m in the process of making the Topsy Turvy H&M engine. I'm trying to figure out how to cut the 44 tooth spur gear on my dividing head (40 to 1 ratio). I've figured out how to cut the 22 tooth (1 turn and 27 holes on the 33 hole plate). The 44 tooth set up I've come up with is .9 turns plus 3 holes on the 33 hole plate.... .9 Turns???? Here is how I've come to this conclusion. 40/44 = .9 4/44. working the fraction to arrive at a number on a plate... 4/44 = 2/22 multiply by 1.5 = 3/33 or three holes on 33 hole plate so that's .9 turns plus 3 holes? How's that going to work?? Any help would be appreciated. Thanks MikeG

Sorry Mike--Can't help you. I cut gears using my rotary table (90:1 ratio) and sector plates. I got my paper charts out and started to take a look, but there is too much difference in our two systems for me to help.---Brian

Hi Mike Using the 33 hole plate set the sector arms so you can advance 30 holes only for each cut on the 44 tooth gear. 40 turns for 1 complete rev so 40x33=1320/44=30 Marcus

Marcus Thank you for your answer, which is exactly how I finally figured it out. Just came in from the shop after making a beautiful brass 44 tooth gear!! MikeG