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 Drill Bits
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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 | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
82° Countersink Angle | 90° Countersink Angle | Optional Collars | ||||||||||
| For Screw Size  | For Drill Bit Size | Body Dia. | Overall Lg. | For Use On | Each | Each | OD | Wd. | Each | |||
Uncoated High-Speed Steel | ||||||||||||
4 Flute | ||||||||||||
| No. 4 | 7/64" | 5/16" | 3/4" | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel, Wood | 0000000 | 000000 | 0000000 | 000000 | 9/16" | 1/4" | 0000000 | 00000 |
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.
Drill-Bit Countersinks with Drill Bit
These countersinks come attached to a high-speed steel jobbers’ bit for drilling and countersinking at the same time. They have a hex shank that fits in all quick-change and standard drill chucks. The bit is held in place with a set screw and can be adjusted up to 1” for different screw lengths. The 82° countersink angle is compatible with the profile of flat- and oval-head inch screws.
For technical drawings and 3-D models, click on a part number.
Countersinks | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
For Screw Size | 82° Countersink Angle | Replacement Drill Bits | ||||||||
| Hard Wood | Drill Bit Size | Body Dia. | Shank Size | Overall Lg. | Max. Hole Drilling Dp. | For Use On | Each | Each | ||
Uncoated High-Speed Steel | ||||||||||
2 Flute | ||||||||||
| No. 4 | 5/64" | 1/2" | 1/4" | 2 9/16" | 1" | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel, Wood | 0000000 | 00000 | 0000000 | 00000 |
Inch Size High-Speed Steel Counterbores with Built-In Pilot
The built-in pilot maintains alignment in the hole.
Titanium nitride (TiN) coated counterbores are more wear and heat resistant than uncoated counterbores.
For technical drawings and 3-D models, click on a part number.
Dia. | Pilot | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| For Screw Size | Body | Shank | Dia. | Lg. | Overall Lg. | Number of Flutes | Flute Style | For Use On | Each | |
Uncoated High-Speed Steel | ||||||||||
| No. 4 | 0.186" | 5/32" | 0.112" | 0.156" | 3 7/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 000000 |
Titanium Nitride (TiN) Coated High-Speed Steel | ||||||||||
| No. 4 | 0.186" | 5/32" | 0.112" | 0.156" | 3 7/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
Oversized High-Speed Steel Counterbores with Built-In Pilot
Use these oversized counterbores when the screw holes in sheets or layers of material are misaligned. The built-in pilot maintains alignment in the hole. The body diameter and pilot diameter account for the 1/32” or 1/64” oversized diameter rating.
Titanium nitride (TiN) coated counterbores are more wear and heat resistant than uncoated counterbores.
For technical drawings and 3-D models, click on a part number.
Dia. | Pilot | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| For Screw Size | Body | Shank | Dia. | Lg. | Overall Lg. | Number of Flutes | Flute Style | For Use On | Each | |
Uncoated High-Speed Steel | ||||||||||
1/64" Oversized | ||||||||||
| No. 4 | 0.206" | 5/32" | 0.128" | 0.156" | 3 7/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 000000 |
1/32" Oversized | ||||||||||
| No. 4 | 0.221" | 5/32" | 0.143" | 0.156" | 3 7/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
Titanium Nitride (TiN) Coated High-Speed Steel | ||||||||||
1/64" Oversized | ||||||||||
| No. 4 | 0.206" | 5/32" | 0.128" | 0.156" | 3 7/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
1/32" Oversized | ||||||||||
| No. 4 | 0.221" | 5/32" | 0.143" | 0.156" | 3 7/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
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. 4 | 0.198" | 0.111" | 0.170" | 2 5/8" | 2 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 000000 |