This R-4 insert is 15mm wide and has a 4" (100mm) radius on each face. This insert is used with the Bear Tooth™ Carbide Turning Tool.
The center hole is sized for use with a #10 screw.
This insert can be used with the old Woodchuck Pen Pro and Woodchuck Uni-Tool. These tools are no longer carried by Bear Tooth Woods, but the Bear Tooth™ Carbide Turning Tool is an equivalent replacement.
This insert will not work with the Easy Wood tools. Use the appropriate 11mm carbide inserts for Easy Wood tools.