Step 9: Jaw Drive Mechanism
Using drill motor mounting bars (part L), quarter-inch carriage bolts, nuts and washers, attach the motor to the lower right-hand side of the moving platform. You'll need to add a couple flat washers under the bottom mounting bar so that the chuck is elevated above the surface of the platform so it’s not dragging on the movable platform.
Attach a quarter inch turnbuckle to the threaded shaft, screwed it on so thread engagement is about a ¼ inch. Drill a hole in the moving platform in line with the center slot of the turnbuckle and about 1/2 inch ahead of the end of the threaded shaft.
Create a turnbuckle guide using carriage bolt, nuts, washers, and nylon quarter inch nuts and washers as shown in the photos.
Position the cable mount wood block (part G) sit it aligns with the opposite end of the turnbuckle. Create a stepped diameter hole to hold actuation cable in this mounting block. Attach the mounting block to the moving platform with T-nuts installed the platform and hex head cap screws, see photos.
On the right-hand side of the turnbuckle using 1 inch long # 6 sheet metal screws to attach the wooden microswitch mounts [part I]. Position them so the front and rear microswitches limit turnbuckle movement as it moves from jaw open to jaw closed positions. That is, the N.C. microswitches need to trip (open) before the turnbuckle bottoms out on anything solid. Number 4 sheet metal screws one half-inch long can be used to mount the microswitches.
Cut actuating cable outer casing 15 ½ inch long and inner cable 22 inches long. Thread the inner cable through the front turnbuckle hole and then thru the mounting block. Install the outer casing and then thread the inner cable through a 1/8 flanged nylon bushing in the mini clamp connecting plate and finally through the 1/8 hole in the ½ carriage bolt. Make a cable clamp by drilling a 3/32 hole in the center of a 10-24 coupling nut and then use a 10-24 screw to clamp the cable within the coupling, see photos.