Counterbore for #8 screw HS

Counterbore

• High Speed Steel
• For #8 Screw
• One piece construction

Use these counter bores create a flat bottomed hole. These special drill bits have a pilot that fits into the already drilled hole. The flutes will widen the hole and create a flat bottom. This flat bottom allows you to have your fastener flush with the surface. These counter bores are designed fillister screws but they should work with your Socket Head screws. You should verify the diameter to make sure.

The data for these Counterbores
#size   pilot dia    cut dia  
#2          .085"         .155"
#4          .111"         .198"
#8          .163"         .285"

Sorry, we don't have these one piece counterbores for any smaller sizes.

The picture shows a counterbore and counter sunk 4-40 socket head screw.