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South Bend 13 lathe - 19tpi

Brannigan

Plastic
Joined
Jan 8, 2018
Does any wise person know which non-standard stud gear can be used on single tumbler, South Bend 13" lathe, to cut 19tpi on a model from around 1940? Unfortunately the banjo does not allow for any change gears... Currently got a second lathe clogging up my workshop just to cut 19tpi as it's a common English thread. Also hoping to get 100% thread accuracy and maintain use of the thread dial. If not possible, reckon I'll have to go down the route of making a new banjo that will allow alternate change gears between the stud gear and gearbox.

All thoughts much appreciated - thanks!
 

GenePoole

Cast Iron
Joined
Dec 8, 2012
Location
St. Louis, MO
I was able to get 27 TPI from my 1966 SB13 by swapping the 64T with a 48T (0.75 ratio) and using the 36TPI setting on the QCGB (36 * 0.75 = 27), but 19TPI might not be so easy since it is a prime number. You'll probably need a 19T, 38T, 57T or 76T gear somewhere in the gear train to achieve this. I don't see any way this works with your thread dial (unless you have a 19TPI lead screw).
 








 
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