1. Manufacturing Technology HPEDSB
Holes
Manufacturing Technology
HPEDSB

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

3. 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

4. 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.

5. 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

6. 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

7. 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