Page "hobbies" Paragraph 224

Tappets and locking bars

Draw-file No. 1 tappet to a smooth fit in its respective slot and square the ends.

Break the end corners with a slight 45 degree chamfer.

Drill a No. 50 hole 1-1/4'' '' from one end and tap 2-56.

( See Fig. 7.

) Put a 2-56 roundhead screw into the hole, cut off the excess threads and file flush with the underside of the bar.

To find the other stop screw position, insert the tappet into the frame and hold the screw head tight against the frame edge.

Scribe a line across the bar on the other end of the tappet, 1/4'' '' plus half the diameter of the 2-56 screw head ( about 5/64'' '' ) away from the frame edge.

Total distance is about 21/64'' ''.

Tend to make this dimension slightly undersize so you can file the screw head to get exactly 1/4'' '' tappet movement.

Drill a No. 50 hole, tap 2-56 and insert a roundhead 2-56 screw as you did on the first end.

Drill a No. 47 hole crosswise through the tappet at the position shown in Figs. 7 and 8.

Repeat these drill and tap operations for each of the tappet bars.