1-7/8 x 8 backplate for 10R Spindles



I have a little used SB, used by USN, 10R, 36” bed, with a 1-⅞” spindle. It has the original 5”, 3 jaw, but only one set of jaws and the run out is bad. They made very few small spindle lathes so If you want a new 3 or 4 jaw, there aren't any unless you change out to the larger spindle, which I don’t need for my work.

Here was my solution:

I purchased a 1-3/4 x 8 , 6” dia cast iron backplate from Little Machine shop for $53. As I was unsure of my internal threading skills,I purchased a 

1-⅞ x8 tap for final threading/cleanup. You need to first increase the bore (check the spec in Machinery Handbook), and then I ran enough threading  runs to get my tap started. If you are good with internal threading or have a machinist friend, the Tap is not needed. 

I purchased a Shars 3 jaw for approx $100, and for a total cost of $150, plus $60 for my “tap insurance”, I have a new, 6”  1-⅞ 3 jaw at 6”. 

Easy to machine the backplate to fit indent in 3 jaw. 

If anyone wants to buy my little used 1-⅞ x 8 TAP, I will sell it for $35 including postage.


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