General Specifications fro Manufacturer's Brochure:
Consists of three (3) guide tubes with internal diameters of:
.670" for 1/2" TO 5/8" diameter barstock
.551" for 1/4" TO 1/2" diameter barstock
.315" for 1/16" TO 1/4" diameter b...
These reduction bushes allow for the fitting of boring bars and drills with a tapered shaft. All sizes are manufactured in a range of capacities. The sleeves are hardened and ground for a good fit for both the holder and the shaft.