stepper settings/ calculation set up

Oops, sorry, I updated what I said. I've been immersed in this stuff with a US based engineer the last couple of days who is working in SI units. This morning he said:

Rod, in your distance traveled calc per pinion rev - my research showed that a 30mm diameter pinion is the pitch diameter. You guys are clever enough to call it by it's useful name

you need the pitch of the belt system

there are Inch and Metric belts available
GT2 for instance is metric 2mm Metric is 5mm or 10mm Standard
the Inch ones are module m=d/z
but better to messure is the outside diameter m=da / 7(z+2)

and d=Workdiameter=m*z
worklengthPerRev= U = d*Pi THATS the Value you need for calculation

if you got the m you got P as m=P / Pi -> P= m * Pi
so you got
d= (z*P) / Pi

Sorry Education Personal