This has been an interesting thread. Wanted to cut some 20 pitch threads on my 1340 Advance lathe that I had not used for threading before, were not 20, found they were 22 pitch. Some head banging, recheck all levers, all as should be according to the charts on lathe. Checked the drive gear train, all as should be. Started trying different pitchs, all tried were not at charted settings. This lathe has 2 shift levers and a 9 position dial, also left/right lever and a threading or power feed lever. Started playing with the 9 position dial,found it it would move about 1 position beyond the 1 or the 9 position. Strange, seemed to be some slack also, with mushy engagement at ether end.
Had seen blue silicone on cover plate instead of a gasket. This was a used lathe, brought by my father about 20 years ago. In for a penny, desided to remove cover. Gear oil in the box, wife not happy about the smell! So the dial turns a pinion gear which moves a rack which has a shift fork on it. Found that the fork mounting screws were loose. Tightened them, still did not move into right position. After watching movement of rack, found pinion was timed to rack wrong. Reset, looks good, moves and stops at each end on position marks.
Putting back together, the shift fork engages a peg on the gear slider but the piece pivots around the main gear cluster and drops down into the case 90 degrees from where it should be. A light weight string looped over it and tied up over the gasket surface. Put RTV grey on gasket surface, and eased cover into place, made sure fork was engaged with peg, pulled out string and replaced fasteners, lightly tighten, try all positions ,turning by hand.
A long story, but now works right.
