The nut size is 11/4 X 2 X 1/4. It was used on a South Bend 10K but the nut can be altered to fit many other lathes.
The item "South Bend lathe 9/10K boring bar holder" is in sale since Thursday, November 7, 2019. This item is in the category "Business & Industrial\CNC, Metalworking & Manufacturing\Metalworking Equipment\Metalworking Lathes". The seller is "5026bruce" and is located in Bangor, Maine.
This item can be shipped to United States.