I have steel broadhead adapters in 100 and 75 grains, 11/32" from several suppliers, they don't seat all of the way into the Grizzly ferrule, ( I assume the Grizzly is 21/64'). There is always about one "thread" on the adapter not seated fully into the broadhead.
I have tried 5/16" and they seem a little to small.
I have found a way to make the 11/32s work by chucking them into a drill press, and while they are spinning, I use a 12" wood ruler wrapped in course emory cloth and hold it against the adapter, mantaining the correct degree of taper.
It works but is time consuming and tedius.
Anyone know of a better way to get them to fit, or a supplier of steel adapters that will fit a Grizzly?
Thanks,
John