Seneca Falls STAR and metric thread

[farmwrench@aol]

I have a Seneca Falls STAR lathe the bed is marked 9x5, but the owner called it a 10". It is backgeared and has a taper atatchment. I know it is possible to cut meteric thread with such a set up is you know the ratios. The previous owner had never used the taper and wasn't sure it was all there.
The only info I have found was from a cool web site in England, www.lathes.co.uk/senecafalls/index.html (http://www.lathes.co.uk/senecafalls/index.html)
Any other info or accessories (the last owner kept many of the other accesories, center rest ect) But I only paid $200 so I can't gripe.

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[SGW]

To cut metric you'll need a compound gear setup to do the conversion. You can get the exact conversion ratio with a 127/100 combination, but gears that big might not fit, and they're expensive. You can come close enough for all practical purposes with a 47/37 combination.

Assuming the change gears are some standard diametral pitch, you ought to be able to get suitable gears from Boston Gear.

The change gears are almost certainly 14 1/2 degree pressure angle. To figure out the diametral pitch, count the number of teeth on a gear, add two, and divide by the diameter in inches. For example, if you have a 32-tooth gear that is 2.125" in diameter, it's 16dp, i.e., (32+2)/2.125
Things being what they are, it probably won't come out precisely, but the results ought to be close enough so you can say with reasonable confidence what the dp is.