Gears

[blackangus]

Hi I don't know if this is the right place for this question but I will ask it anyway. I want to make a gear with 80 teeth and 18 dp when I calculate the OD I come up with 4.555555555555556 I'm just not sure of what I should use for an exact OD. Any help would be greatly appreciated. Thanks

 

[gbritnell]

18/80=4.44444 P.D.

 

[gbritnell]

Sorry about that. That's the P.D. You have to add the addendum 1/18 = .0555 x 2 =.1111 + 4.444 = 4.5555

 

[tornitore45]

You calculated the OD correctly 4.555555555555556
I doubt you can machine to a femto-inch (10exp-15) accuracy so somewhere between the correct dimension an 4.55 +/- 0.005 you should have a working gear.