In a pinch, one could probably get away with using a 1.0 thread to fit a 25 TPI. As long as the length of the threaded section is short enough to avoid jamming and the thread was cut loose.

If you take the decimal equivilent of 25TPI (1/25 = .04), it is nearly the same as a 1.0M pitch (1.0/25.4 = .0394"). Granted, it is best to use the right thread. And as Donald pointed out, there are lathes today which use the "electronic lead screws" which make machining the right threads a dream.

Adam Dau