The above knurl is designed to fit into a quick change tool holder block.
The tightner (upper left), the handle is 1/4″ steel rod about 3 inches long. The handle hub is 3/4″ dia. brass rod and should be tall enough to allow the handle to clear the height adjustment bolt on the tool holder block. It should be cross drilled to receive the handle, also drilled and tapped to receive the 5 inch threaded rod. The threaded rod is pinned in place. The top bearing block is 3/4″ dia. by 3/4″ brass rod, with a flat milled on the top and a 5/16″ through hole. The bottom bearing block is as per the top block, except that it should be drilled and tapped to receive the 1/4″ threaded rod. A steel washer is used to reduce friction.
The right and left housing plates, (3″ by 4″ by 3/8″ steel) are each identical, except that the left plate has all 1/4″ holes, while the right plate has two of the holes threaded for 1/4″ bolt. (the uppermost hole should have been marked “1/4 thread”)
The knurling levers: Made from 1″ by 3/4″ by 4.5″ brass bar stock. I used brass because it was the only stock that size that I had. I milled the knurl pocket (s) at the same time by butting them end to end in order to ensure that they were perfectly in line. I also drilled the 3/4 in dia. semi circular cutouts at the same time by clamping the two levers top to top in the vice. Drill the spring pocket about 1/2″ deep and a dia to suit whatever spring you have.
The diagional line near the knurl pocket is a .030+ – drilled hole for a lock wire to pass through it (and a hole in the end of the knurl axel) to secure the axel in place. I considered set screw to be prettier but far less reliable.
The housing plate separator (spacer) (1′ by 3/4″ by 2.5 brass bar stock) Brass because it was . . . Add as little shim stock as is needed to allow the levers to operate snugly. I radiused two of the corners to allow the levers to close a bit more.
The mounting block (3″ by 3/4″ by 2.5″ brass bar stock) Brass because it was . . . I milled shoulders on mine to provide clearance for the tool holder height adjustment nut and a flush fit in the holder.
Author: Bill Darby