Dividing Head Calculation Double Check

[Mister Ed]

I need verification for my calculations for my dividing head. I need to increment 77 degrees. 40:1 dividing head.
Based on my calculations I need 5 full turns and 5/9 of a turn, So, I could go 15 holes on the 27 hole circle or 10 on the 18 ... correct?

I don't use this thing often and when I do I am usually dividing the circle into X number of divisions.

Thanks - Ed

 

[Ed ke6bnl]

ok total newby and never done it, speaking kinda out loud on paper. seems like 9 degrees per rev. so that means 8 revs gets you to 72 degrees + you need 5 more degrees 5/9 or 15/27 so I see 8 revs + 15 of the 27 plate. Ed as well

 

[Zanfar]

As an aspiring machinist without any machines, this is one I can actually contribute to.

Ed is correct, I get 8 + 5/9 turns of the handle, so 8 full turns and 15 holes on the 27 circle, or 8 turns and 10 holes on the 18 circle