We take a lot of care in making this product. First, we use oversize 1144 heat-treated shafting material. We turn the OD, and then we drill the socket for the insert. Next, all in the same hold, we skin the outside and bore the ID so the entire part is concentric.

The bore is .500 +.0005; the hat insert is turned to .4998 so the fit is very good. The contact on the hat is out at the outside and the saw does not touch the inside radius of the hat.

The saw is not included.