This brought up a memory, from the first shop I worked at.  Was grinding the seats on a Ford flathead V-8, in the case with the stones and shafts were a set with a valve stem diameter of 1/2 inch.  Just huge in comparison to the rest.  Discovered they were for a commercial Ford engine that used sodium in a hollow valve stem.  The sodum sloshing inside cooled the valve in an attempt keep the seat from burning.  We found an article saying to dispose of them carefully, as the liquid sodium could  burn or explode.  Watching for a Sioux set now.

As seen from Woodstock .......

When I had my shop, we had a Black & Decker seat grinder. I can't remember which valve grinder we had, it might have been a Sioux, but I bought it used from our local NAPA parts store machine shop. It was said to be worn out but once I cleaned it up the only thing I could find wrong was excessive play in the guides that were used in the mechanism to slide the valve back and forth across the grinding stone. My father-in-law was a tool and die maker so I asked him to take the guides to work and remove the clearance plus a little more. When I got them back, I installed with some shim stock to get the clearance just right so the table slid smoothly without any chatter when cutting the valve. That grinder served me well up until I sold the place. I wish I had a setup now as this sort of work is getting hard to get done as the automotive machine shops close up one at a time.

Lou Manglass

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...   

Very cloudy here in Pa. The few chances i got out at work, i could only see it for a few seconds before clouds covered it again. Would be interesting to see it through a telescope.