Mine are 38/17 and 32/23 combinations. These both provide the same centre to centre of 2.95/2" Gary's do not.
I think my alloy end cover may be a little sloppy as the centre to centre distance did not match.
My gears have been replaced at some time and not all of the originals are there to be found. I've only used the 2" combo as mine also has a VFD which seems to cover all the feeds I have needed, or might need.
An alternative route would be to work back from the worm drive and table reduction drive to arrive at the feed rates quoted in the literature!
Edited to add that there is a pic with countable gear teeth on the lathes dot co site. The smallest gear is a 15. As the centre to centre distances for 15 and 38 is 2.85/2" and that for a 23 and 32 is 2.95/2", we may have a problem, Houston!
Mine works and so does Gary's!
Edited By not done it yet on 21/09/2017 16:44:58