This is the stop block attached to the front slotted vertical slide adjustment for the table. The whole is an all metal foot operated mortising machine. It has a chuck to hold the chisel bits [ a bent one in chuck ]; with a small [ 3 1/4 X 22 1/2 ] iron table which is adjustable vertically and can swivel for angle cuts. The table has hold down rods which are also adjustable. The verticle unit is bolted to a three leg, claw footed base. There does not appear to be any rotating parts to drive a drill bit, etc.; thus, the machine must have been used to creat square corners in a pre-drilled hole.