Originally Posted by RotarySMP To make imperial threads on a metric lathe, you will need 57 tooth gear somewhere in the change gears. (25.4:1 --> 254 is divisable by 57). I think you can buy these from www.littlemachineshop.com (Can't access the website today). |
Could you explain that? 254 is divisable by 57, as my calculator does not blow up.
My small lathes have a 127 tooth gear to convert metric -> imperial. As far as I know this is the smallest wheel that will do the conversion with no error. There are other combinations (using 2 wheels) that give a very small error.
My big one have a 90 tooth wheel, but it's a strange beast having a metric gearbox driving an imperial leadscrew. And that's on a Belgian lathe! Need I say I never used the thread dial? Good thing it reverses by just throwing a handle.
This is a thing you might consider in choosing system. If you do much threading in one system, either buy one with that system in the leadscrew, or make sure it can reverse using clutches. The clasp nut cannot be used when threading the "foreign" system. And the motor really don't like the frequent start/stop reversing. And with no clutch at all, combined with no use of clasp nut, you can not run threads up to a greater diameter.