Bought a valve seat grinder on Ebay and one of the stone holders wasn't for the Sioux driver in the kit. It was for a Thor/Black & Decker driver with a 5/8 hex and .375 top diameter pilots. I took it apart and bored the spindle to fit Sioux style .385 pilots. It is so old the shell is brass and they used two extra bearings as spacers. I swapped the bearings to use the two unused bearings for the spindle and set out to make a compatible 1/2 hex to fit the driver.
Sacrificing a 1/2 deep impact socket to get an internal hex was a easy way to get that part. I made a top to match the original dimensions and press fit the socket section in it. The whole thing was and is press fits and it relies on friction to transmit the torque of the driver to the stone.
Here it is with the driver and the other holder for the kit. Now I'm waiting for and order from Goodson's with stones and carbide sizing balls.
Ground the valve seats in my open sky shop. Intake width .060 exhaust .080. Tried to get the intake pattern towards the outside of the valve face and exhausts in the middle.
Stem clearance checking. This is the best I've got to use. A magnetic mount and dial indicator set on the stem as close to the guide bore as possible and as square as possible.
One exhaust was a little tight and on inspection there was a burr in the bore. A quick trip with the hone cleaned that up. The goal was .001 on intakes and .0025 on exhaust. With his setup's limitations I think it is real close to that.
