Most of the older lathes had change-gears as well as the quick-change gearbox. An inch leadscrew was very common on metric lathes - to cut metric threads you just had to include a 127 tooth gear in the change-gears (an inch is 25.4 mm, and 127 is half of 254). Those lathes came with a stack of about 8 or 10 change-gears, and you assembled a gear train to cut the thread you wanted. Typically there was a leads and feeds data plate attached to the lathe - here's mine:
[Linked Image]

However change-gears eventually became uncommon - they made lathes very versatile, but set-up took longer.