Dave, It looks like a 35t drive gear, 40t driven gear, gearbox B6 would get your 1.75mm pitch.

As to the spreadsheet, I've done one for the Grizzly G0602 and G4000. I haven't ventured into other lathes.

In order to understand all the ratios, you have to know what;s going on in the gearbox. The A, B, C, D, & E positions are in the ratio 1:2:4:8:16 (as you go from A to E, the pitch decreases and the tpi increases). It appears that the ratios of the numbered gears are 16:18:19:20:22:24:26:28 for positions 1- 8. More than likely, this is the actual number of teeth on the gears.

When the drive and driven gears are equal, position C6 gives 1 mm of travel for each revolution of the spindle. Increasing the ratio of drive to driven increases the travel by the ratio of the gears so changing the driven gear from 40t to 30t will increase the travel by the same ratio (40/30) or 1.333 mm per revolution.

My head spins as well but I find hitting the brandy bottle just makes it spin worse.