It is beveled at the lower end so as to rest snugly against a cleat nailed down at the proper place on the floor.

The board is held in place by a loop of iron, B, which hooks into the holes in the trough of the grindstone.

In the board a series of holes (say 1" in diameter) are bored.

These run parallel to the floor when the board is in place, and receive the end of the tool-holder.

The tool-holder consists of four parts: (1) a strip C, 1-1/2" thick, and as wide as the widest plane-bit to be ground.