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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About Drill Bits
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High-Speed Steel Drill-Point Countersinks for Screws
A small drill point at the tip lets you use the same tool for drilling and countersinking holes. 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.
For technical drawings and 3-D models, click on a part number.
Dia. | 82° Countersink Angle | ||||||
|---|---|---|---|---|---|---|---|
| For Screw Size  | Body | Shank | Drill Tip | Overall Lg. | For Use On | Each | |
Uncoated High-Speed Steel | |||||||
2 Flute | |||||||
| No. 8 | 7/16" | 1/4" | 0.166" | 2" | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 000000 |
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. 8 | 11/64" | 3/8" | 7/8" | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel, Wood | 0000000 | 000000 | 5/8" | 1/4" | 0000000 | 00000 |
90° Countersink Angle | ||||||||||
Uncoated High-Speed Steel | ||||||||||
4 Flute | ||||||||||
| No. 8 | 11/64" | 3/8" | 7/8" | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel, Wood | 0000000 | 00000 | 5/8" | 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.
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 | Replacement Drill Bits | ||||||||||
| Hard Wood | Soft 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. 6 | No. 8 | 7/64" | 1/2" | 1/4" | 2 27/32" | 1" | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel, Wood | 0000000 | 00000 | 0000000 | 00000 |
| No. 8 | No. 10 | 1/8" | 1/2" | 1/4" | 2 31/32" | 1" | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel, Wood | 0000000 | 0000 | 0000000 | 0000 |
Countersinking Drill Bits for Screws
Also known as step drill bits, these bits countersink as they drill. The 82° countersink angle is compatible with the profile of flat- and oval-head inch screws. After multiple sharpenings, the drill bit diameter may become smaller.
For technical drawings and 3-D models, click on a part number.
Dia. | Lg. | 82° Countersink Angle | |||||||
|---|---|---|---|---|---|---|---|---|---|
| For Screw Size | Body | Step | Step | Overall | Shank Dia. | Point Angle | For Use On | Each | |
Uncoated High-Speed Steel | |||||||||
2 Flute | |||||||||
| No. 8 | 0.332" | 0.169" | 1/2" | 4 3/4" | 0.3320" | 118° | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 000000 |
Quick-Change Combination Countersinking Drill and Screwdriver Bits
Drill, countersink, and drive screws without switching three separate bits in and out of your power tool. With a single hand, flip between drilling countersunk holes and driving screws. The countersinking drill and screwdriver bit are secured with set screws, so you can switch them out for any bits with a 1/4” hex shank.
The countersinking drill has an 82° angle, allowing inch-sized flat- and oval-head screws to sit flush with the surface.
For technical drawings and 3-D models, click on a part number.
Combination Countersinking Drill and Screwdriver Bits | Replacement Drill Bits | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| For Screw Size | Drill Bit Size | Countersink Body Dia. | Max. Hole Drilling Dp. | Countersink Angle | Screwdriver Bit Size | For Drive Style | Adapter Hex Shank Size | Adapter Lg. | For Use On | Each | Each | ||
Black-Oxide High-Speed Steel Countersink | |||||||||||||
4 Countersink Flutes | |||||||||||||
| No. 8 | 7/64" | 3/8" | 2" | 82° | No. 2 | Phillips | 5/16" | 3 3/4" | Aluminum, Fiberglass, Plastic, Wood | 0000000 | 000000 | 0000000 | 00000 |
High-Speed Steel Drill-Point Countersink Sets for Screws
Small drill points let you drill and countersink holes with the same tool. 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.
82° Countersink Angle | ||||||||
|---|---|---|---|---|---|---|---|---|
| For Screw Size | Number of Pieces | Number of Flutes | Number of Countersinking Ends | Shank Type | For Use On | Container Type | Each | |
Uncoated High-Speed Steel | ||||||||
| No. 5, No. 6, No. 8, No. 10, No. 12, 1/4", 5/16", 3/8" | 8 | 2 | 1 | Round | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | Plastic Case | 00000000 | 0000000 |
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. 8 | 0.272" | 1/4" | 0.164" | 0.250" | 5" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 000000 |
Titanium Nitride (TiN) Coated High-Speed Steel | ||||||||||
| No. 8 | 0.272" | 1/4" | 0.164" | 0.250" | 5" | 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. 8 | 0.288" | 1/4" | 0.18" | 0.250" | 5" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 000000 |
1/32" Oversized | ||||||||||
| No. 8 | 0.303" | 1/4" | 0.195" | 0.250" | 5" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
Titanium Nitride (TiN) Coated High-Speed Steel | ||||||||||
1/64" Oversized | ||||||||||
| No. 8 | 0.288" | 1/4" | 0.18" | 0.250" | 5" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
1/32" Oversized | ||||||||||
| No. 8 | 0.303" | 1/4" | 0.195" | 0.250" | 5" | 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. 8 | 0.285" | 0.163" | 0.120" | 2 3/4" | 2 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 000000 |
Inch Size Drill-Point Counterbores
Drill and counterbore holes with enough clearance for socket head screws without changing tools. The longer the counterbore, the thicker the material it can drill.
For technical drawings and 3-D models, click on a part number.
Dia. | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| For Screw Size | Body | Shank | Drill Tip | Overall Lg. | Max. Hole Drilling Dp. | Number of Flutes | For Use On | Each | |
Uncoated High-Speed Steel | |||||||||
| No. 8 | 0.290" | 5/16" | 0.178" | 1 15/32" | 0.281" | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 000000 |
| No. 8 | 0.290" | 3/8" | 0.178" | 2 1/4" | 0.534" | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 000000000 | 00000 |
Counterboring Drill Bits
Often called step drill bits, these drill and counterbore holes at the same time. After drilling and counterboring, tap the hole and install your fastener. The body diameter may decrease after multiple sharpenings.
For technical drawings and 3-D models, click on a part number.
Dia. | Lg. | |||||||
|---|---|---|---|---|---|---|---|---|
| For Screw Size | Body | Step | Step | Overall | Point Angle | For Use On | Each | |
Uncoated High-Speed Steel | ||||||||
| No. 8 | 0.290" | 0.178" | 1/2" | 4 1/4" | 118° | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 000000 |
Oversized Long-Life Counterboring Drill Bits
These counterbores are often used when screw holes in sheets or layers are misaligned. Also known as subland drill bits, they last longer than standard counterboring drill bits because the diameter stays the same after sharpening. They drill and counterbore at the same time. After drilling and counterboring, tap the hole and install your fastener. The diameters account for the 1/32” or 1/64” oversized diameter rating.
For technical drawings and 3-D models, click on a part number.
Dia. | Lg. | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| For Screw Size | Body | Step | Step | Overall | Number of Flutes | Point Angle | For Use On | Each | |
Uncoated High-Speed Steel | |||||||||
1/64" Oversized | |||||||||
| No. 8 | 0.281" | 0.175" | 3/8" | 4 1/4" | 2 | 118° | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 000000 |
Long-Life Counterboring Drill Bits
Also known as subland drill bits, these last longer than standard counterboring drill bits because the diameter stays the same after sharpening. They drill and counterbore at the same time. After drilling and counterboring, tap the hole and install your fastener.
For technical drawings and 3-D models, click on a part number.
Dia. | Lg. | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| For Screw Size | Body | Step | Step | Overall | Number of Flutes | Point Angle | For Use On | Each | |
Uncoated High-Speed Steel | |||||||||
| No. 8 | 0.272" | 0.164" | 3/8" | 2 11/16" | 2 | 118° | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 000000 |