Cutting Metric Threads on a Logan with standard gears and gearbox Version 3

I have added a check for gears fitting. You can enter any gear train and the spreadsheet will check that the gear train fits. I have added two sheets. The first adds a 33T gear and yielding a 4 -> 30 PPM error. The second sheet adds 20T, 25T, 27T, 33T gears to give 4 PPM error. The Microsoft small basic program ( free from Microsoft) is on the last sheet and lets you calculate any thread with any set of gears ( with quick change gearbox ) and returns the lowest error possible with those gears.

I have made the tolerance to metric threads tighter. I have verified that all gears calculated fit on lathe. I have included, on sheet 2, a basic program written in Microsoft small basic ( which you can download for free ) that brute force calculates the gear combinations that give the tightest tolerance to the metric pitch specified on Line 1.

You can use this to enter the gears you have.

When using this program you will get many gear combinations, not all of which fit. You can load some of these into the spreadsheet and swap all gears in the odd columns and swap all of the gears in the even columns. It took me awhile to find combinations that fit on the lathe. I sat at a table with the gears an a couple of 5/8 rods to check fit.