Manufacturing Technology HPEDSB Holes Manufacturing Technology HPEDSB

Hole Types Drilled and/or Reamed Holes Threaded Holes Countersink Holes Counterbore Holes

Drilled Holes (Straight) Uses a spiral flute drill bit to create a hole of a desired size in a workpiece Can be drilled through a part or to specific depth Will never measure the exact size of the drill bit because of drill wander or size variations in bits Can be started by using a center punch to mark location or by first pre-drilling a hole using a center drill

Reamed Holes A hole that is extremely close in tolerance to desired size (usually within 0.001”) Created by first drilling with a drill bit that is 1/32-1/64” smaller than desired final size Used for things such as locating holes, bearing fits, etc.

Threaded Holes A hole that contains screw threads for fastening purposes Created in a 3-Step Process: Center Drill in desired location Drill to correct Tap Drill Size Create threads using a Tap

Countersink Holes A drilled hole that also contains a conical taper at the top of the hole that allows a flat head screw to sit flush with the surface of the work piece Created by following common drilling steps and then using a countersinking tool to create the countersink at the top of the drilled hole

Counterbore Hole A drilled hole that is bored oversize at the top surface to a specific diameter and depth, to allow for a Socket Head Cap Screw or other component to sit flush with the surface of the work piece Created by following the common drilling steps and boring using a special counterboring tool