My Sioux Valve Grinder # 645L and Portable Seat Grinder 1710S
Sioux made valve grinders since the early 1920's. A must have single use machine for any antique car enthusiast such as myself. In the early days, up until the 1970's and introduction of unleaded gasoline, the valves on cars needed resurfacing between 50,000 to 70,000 miles. And it was cheaper to grind the old valves rather than purchasing new.
After cleaning up the valves. The flat end is ground square to the stem. Then a small 45 degree chamfer is added flat end. Making for easier insertion in the head of block. But most important for truing the valve in the Sioux grinder head. Along with setting a stop making all valves the same length. Only old timer's know and understand this. I have read several poster's saying that they cannot get the valve to run truer than .005”. Saying that the three jaws in the work-head is not enough to hold the valve stem true. When in practice The back end of the work-head has a stop with a reverse taper. That center's the valve stem. And the three small jaws grabs 4” of 5” toward the valve head. And indeed makes for quick and accurate setup. Putting a test indicator the revolving valve reveals the TIR (Total Indicator Reading) of less than .001”.
This is a Sioux Portable Valve Seat Grinder. The kit contains the power unit, numerous grinding wheels, positioning shafts, and diamond wheel dresser. This tool in a must have for quick and accurate valve seat grinding of flat head engines. The seat can be resurfaced without removing the engine from the car. Being that most early cars were valve in block design this was a very popular tool to own. However it's still can be used in valve in head engines. But many home mechanics just drop the heads off at a machine shop for someone else to do all the valve work...