Lathe gear calculation | Model Engineer
Asked a similar question some time ago but forgotten the answer.....doh! Could some kind soul take 5 minutes and enlighten me on how to calculate lathe gear changes required for selective pitches please? I can see on machine what gears I need but how exactly does this work out eg. my machine has 8tpi leadscrew, I have 20,30,40,50,55,60,63,70,75 + 80 gears. For a 26tpi thread I would need 70, 65, 30 + 60 gears but how does the maths work here exactly? My previous thread a gentlemen mentioned the 127/100 rule, what does that mean and what bearing does it have on change gears? Many thanks onc...