About Counterbores
Counterboring—Enlarge the top of an existing hole to create a cylindrical-shaped opening with a flat bottom that acts as a seat for the head of a screw or wood plug.
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About Countersinks
Countersinks cut a cone-shaped opening to install screws and rivets flush with a surface or hold workpieces between centers on a lathe. They can also be used for chamfering and deburring.
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High-Speed Steel Drill-Bit Countersinks for Screws
For use on wood, plastic, and most metals, these countersinks attach to a drill bit (sold separately) to countersink and drill holes at the same time. They attach to the drill bit with two set screws and the position can be adjusted for different screw lengths. An 82° countersink angle is compatible with the profile of flat- and oval-head inch screws; a 90° countersink angle is compatible with the profile of flat- and oval-head metric screws and is also good for deburring.
Optional collar (not included) controls the cutting depth of your countersink. It attaches with two set screws.
For technical drawings and 3-D models, click on a part number.
Countersinks | Optional Collars | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| For Screw Size  | For Drill Bit Size | Body Dia. | Overall Lg. | For Use On | Each | OD | Wd. | Each | ||
82° Countersink Angle | ||||||||||
Uncoated High-Speed Steel | ||||||||||
4 Flute | ||||||||||
| No. 3 | 3/32" | 1/4" | 3/4" | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel, Wood | 0000000 | 000000 | 1/2" | 1/4" | 0000000 | 00000 |
90° Countersink Angle | ||||||||||
Uncoated High-Speed Steel | ||||||||||
4 Flute | ||||||||||
| No. 3 | 3/32" | 1/4" | 3/4" | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel, Wood | 0000000 | 00000 | 1/2" | 1/4" | 0000000 | 0000 |
Carbon Steel Drill-Bit Countersinks for Screws
Only for use on wood and plastic, these countersinks attach to a drill bit (sold separately) to countersink and drill holes at the same time. They attach to the drill bit with two set screws and the position can be adjusted for different screw lengths. The 82° countersink angle is compatible with the profile of flat- and oval-head inch screws.
Optional collar (not included) controls the cutting depth of your countersink. It attaches with two set screws.
For technical drawings and 3-D models, click on a part number.
Counterbores for High-Profile Rounded-Head Screws
The built-in pilot maintains alignment in the hole.
For technical drawings and 3-D models, click on a part number.
Pilot | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| For Screw Size | Body Dia. | Head Dia. | Lg. | Overall Lg. | Number of Flutes | Flute Style | For Use On | Each | |
Uncoated High-Speed Steel | |||||||||
| No. 3 | 0.176" | 0.098" | 0.120" | 2 1/2" | 2 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 000000 |