HolesHoles

Manufacturing TechnologyManufacturing Technology

Bayside Secondary SchoolBayside Secondary School

HPEDSBHPEDSB

Hole TypesHole Types

Drilled and/or Drilled and/or Reamed HolesReamed Holes

Threaded HolesThreaded Holes

Countersink HolesCountersink Holes Counterbore HolesCounterbore Holes

Drilled Holes (Straight)Drilled Holes (Straight)

• Uses a spiral flute drill bit to create a Uses a spiral flute drill bit to create a hole of a desired size in a workpiecehole of a desired size in a workpiece

• Can be drilled through a part or to Can be drilled through a part or to specific depthspecific depth

• Will never measure the exact size of the Will never measure the exact size of the drill bit because of drill wander or size drill bit because of drill wander or size variations in bitsvariations in bits

• Can be started by using a center punch Can be started by using a center punch to mark location or by first pre-drilling a to mark location or by first pre-drilling a hole using a center drillhole using a center drill

Reamed HolesReamed Holes

• A hole that is extremely close in A hole that is extremely close in tolerance to desired size (usually tolerance to desired size (usually within 0.001”)within 0.001”)

• Created by first drilling with a drill Created by first drilling with a drill bit that is 1/32-1/64” smaller than bit that is 1/32-1/64” smaller than desired final sizedesired final size

• Used for things such as locating Used for things such as locating holes, bearing fits, etc.holes, bearing fits, etc.

Threaded HolesThreaded Holes

• A hole that contains screw threads A hole that contains screw threads for fastening purposesfor fastening purposes

• Created in a 3-Step Process:Created in a 3-Step Process:– Center Drill in desired locationCenter Drill in desired location– Drill to correct Tap Drill SizeDrill to correct Tap Drill Size– Create threads using a TapCreate threads using a Tap

Countersink HolesCountersink Holes

• A drilled hole that also contains a conical A drilled hole that also contains a conical taper at the top of the hole that allows a taper at the top of the hole that allows a flat head screw to sit flush with the flat head screw to sit flush with the surface of the work piecesurface of the work piece

• Created by following common drilling Created by following common drilling steps and then using a countersinking steps and then using a countersinking tool to create the countersink at the top tool to create the countersink at the top of the drilled holeof the drilled hole

Counterbore HoleCounterbore Hole

• A drilled hole that is bored oversize at A drilled hole that is bored oversize at the top surface to a specific diameter the top surface to a specific diameter and depth, to allow for a Socket Head and depth, to allow for a Socket Head Cap Screw or other component to sit Cap Screw or other component to sit flush with the surface of the work pieceflush with the surface of the work piece

• Created by following the common Created by following the common drilling steps and boring using a special drilling steps and boring using a special counterboring toolcounterboring tool