Function of Grindstone

[Dan England]

After reading the responses, I took another look at the stone this morning. The outer surface (where the tread is located on a tire) has a distinct and continuous groove. The groove is not centrally located as it is about 2 inches from the edge of the wheel. Going to the sides of the grindstone, one entire side is quite rough. The other side is much smoother, as though the bumps and indentations have been worn away. Is the stone large enough to have been part of a gristmill. In a gristmill, would the grinding be on the outer surface as defined above or would the grinding action be done on the side of the stone. I would think, if used to sharpen tools, the wear would be on the outer surface rather than on the side. Let me know what you think. Dan

[Dan England]

Grumpy: There are no grooves on the sides and the sides aren't wavy. Both sides are straight, the only difference being rough vs smooth. Dan

[Don McCombs]

Millstones are usually much larger than the 17 inch diameter that you described. The channels or grooves that Grump mentions caused the grain deposited in the center of the stone to move outward as the stone turned. Otherwise, the grain would stay under the millstone and be ground to a fine powder. The groove or wear on the circumference of your stone is from sharpening small tools, like dressing the point on a punch or chisel. Frequently, the sides of the stone were also used, accounting for the stone being smoother on one side. You'll see the same wear patterns on your smaller bench grinder wheels.

Here's a millstone.
http://en.wikipedia.org/wiki/Millstone

[Paul B]

Millstones are normally cut from granite or other hard stone, and have grooves cut into the sides. They were used in pairs, one turning, one fixed, and the grain was fed thru the center of the fixed stone to the grooves in the stone where it was ground into meal as it made its way to the outside edge of the stones, where it was collected. You need hard stones to keep from getting stone dust/chips in the meal you are grinding.

Grindstones are normally sandstone or other soft gritty stone, and are smooth sided.

[Dan England]

Paul: The stone is the soft and gritty kind. Each characteristic seems to confirm that it is a grindstone used for working metal. Dan