These are hollow square mortise chisels and bits, made by Fisch of Austria. Sharp cutting edges on both the chisel and bits quickly hog out mortises. Correct setting of the bit in the mortise chisel will ensure successful cutting of the tool and a long life for the tool. First place the chisel into its socket in the attachment. Put a dime between the face of the socket and the shoulder of the chisel to prevent the chisel being pushed fully home, tighten down screw to hold the chisel in place. Now fit the bit into the chuck and push it as far as possible into the chisel and secure. Slacken off the screw holding the chisel, remove the coin, push the chisel fully home again, and tighten the screw again. This method allows sufficient clearance for the bit to run smoothly in the chisel and begin to cut just ahead of the chisel.
Replacement bits are available - and to our knowledge will only fit Fisch Hollow mortise chisels.
Made in Austria by Fisch.