A(Fig. 79) is a flat board, on the edges of which are screwed the projecting pieces, b, c, d. e is a piece of wood bearing against the ends of b c, and which forms the straight edge for the cutter or diamond. f is the line which the diamond will make when held against e. From this line the size of the plates is set out and marked on the board, or a stop is fixed, and by two cuts you have a glass exactly square, provided the Hoard has been made square in the first instance. - (A. Killar.)

Fig. 79.

Glass Cutting Board 10061