James ManningDrill, Ream, Counterbore,

Countersink, and Tap

Requirements:1. 1/4 “ Reamed hole2. Counterbore a clearance hole for a

3/8-16 SHCS3. Countersink a clearance hole for a ¼-

20 FHMS4. Tap a ¼-20 x ½” deep thread,

Clearance drill back side to ½” depth5. Chamfer a 45 degree angle on the

bottom

Chamfered edges Tapped, Deep Threaded and machined a half inch back into block

Counterbore,Drilled & tapped

Countersink,Drilled & Reamed Materials Used:

• 3” x 3” x 1” steel block• Manual Mill• Manual Lathe