Review on KangTeer Carbide Burr: 12Mm Diameter Tree Shape With Double-Cut Tungsten Carbide For Rotary File Cutting Burs, 1/4" Shank For Rotary Drills And Die Grinders by Jason Elliss

This product was a gift to use in 1/4" shaft air grinder. When finally need burr found it kept working out of grinder regardless of cleaning air grinder collet, retightening etc. Used a different burr that had no problems. Finally got smart and measured shafts of both burrs. Other burr measured exactly 0.250" this burr measured 0.236" (6.0mm). The smaller shaft will not tighten in my 1/4" (0.250) collet, which makes it an $11.99 worthless burr. It is now pass Best Buy return time. 1/4" (0.250") as described is not 9mm (0.236')