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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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. 5 | 0.220" | 1/4" | 0.138" | 1 7/32" | 0.25" | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 000000 |
| No. 5 | 0.220" | 1/4" | 0.138" | 2" | 0.414" | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 000000000 | 00000 |
| No. 6 | 0.242" | 1/4" | 0.15" | 1 7/32" | 0.25" | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| No. 6 | 0.242" | 1/4" | 0.15" | 2" | 0.45" | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 000000000 | 00000 |
| No. 8 | 0.290" | 5/16" | 0.178" | 1 15/32" | 0.281" | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| No. 8 | 0.290" | 3/8" | 0.178" | 2 1/4" | 0.534" | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 000000000 | 00000 |
| No. 10 | 0.332" | 5/16" | 0.2" | 1 1/2" | 0.312" | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| No. 10 | 0.332" | 3/8" | 0.2" | 2 1/4" | 0.6" | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 000000000 | 00000 |
| 1/4" | 0.406" | 3/8" | 0.28" | 2 3/4" | 0.84" | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 000000000 | 00000 |
| 1/4" | 0.406" | 7/16" | 0.28" | 1 3/4" | 0.375" | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| 5/16" | 0.490" | 1/2" | 0.34" | 1 15/16" | 0.375" | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| 5/16" | 0.490" | 1/2" | 0.34" | 3" | 1.02" | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 000000000 | 00000 |
| 3/8" | 0.593" | 1/2" | 0.406" | 3 1/2" | 1.218" | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 000000000 | 00000 |
| 3/8" | 0.593" | 5/8" | 0.406" | 2 11/32" | 0.468" | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| 7/16" | 0.687" | 1/2" | 0.468" | 4" | 1.404" | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 000000000 | 00000 |
| 7/16" | 0.687" | 5/8" | 0.468" | 2 1/2" | 0.5" | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| 1/2" | 0.781" | 1/2" | 0.532" | 4 1/2" | 1.596" | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 000000000 | 00000 |
| 1/2" | 0.781" | 5/8" | 0.532" | 2 11/16" | 0.562" | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
Metric Size Drill-Point Counterbores
The same tool lets you drill and counterbore holes with enough clearance for socket head screws.
For technical drawings and 3-D models, click on a part number.
Dia. | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| For Screw Size, mm | Body, mm | Shank | Drill Tip, mm | Overall Lg. | Maximum Hole Drilling Depth, mm | Number of Flutes | For Use On | Each | |
Uncoated High-Speed Steel | |||||||||
| 3 | 5.95 | 1/4" | 3.57 | 1 1/4" | 6.35 | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 000000 |
| 4 | 7.54 | 1/4" | 4.36 | 1 3/8" | 7.54 | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| 5 | 9.13 | 5/16" | 5.55 | 1 1/2" | 7.94 | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| 6 | 10.71 | 5/16" | 6.35 | 1 9/16" | 9.52 | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| 8 | 13.49 | 7/16" | 8.73 | 1 13/16" | 11.11 | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| 10 | 16.66 | 1/2" | 10.32 | 2 1/16" | 14.29 | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| 12 | 18.75 | 5/8" | 12.7 | 2 7/16" | 15.87 | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| 14 | 21.82 | 5/8" | 14.68 | 2 5/8" | 16.67 | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| 16 | 24.6 | 5/8" | 16.67 | 2 3/4" | 17.46 | 2 | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
Drill-Bit Counterbores with Drill Bit
These counterbores are attached to a drill bit for drilling and counterboring in a single step. Use them to create flat bottomed holes that act as seats for the heads of lag screws, washer head screws, and tee nuts. All have a 1/4" hex shank that fits quick-change drill chucks, power screwdrivers, and impact drivers. Lock the drill bit in place with the included set screw. For tough resistance to wear, corrosion, and heat, the drill bit is titanium nitride (TiN) coated.
Use the optional rotating depth stops to drill holes to a precise depth. The end of the collar has a ring that rotates separately from the body. When the ring touches your workpiece, it stops moving to prevent scratches or rub marks. The wide opening leaves room for chips to clear the drilling area.
Counterbores | Replacement Drill Bits | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Shank | Each | ||||||||||||
| Body Dia. | Drill Bit Size | Overall Lg. | Max. Hole Drilling Dp. | Type | Size | Drill Bit Material | Number of Flutes | For Use On | Each | 1-5 | 6-Up | ||
Black-Oxide Steel | |||||||||||||
| 3/8" | 1/8" | 2 7/8" | 1.1" | Hex | 1/4" | Titanium Nitride (TiN) Coated High-Speed Steel | 3 | Aluminum, Brass, Plastic, Wood | 0000000 | 000000 | 0000000 | 00000 | 00000 |
| 1/2" | 1/8" | 2 7/8" | 1.2" | Hex | 1/4" | Titanium Nitride (TiN) Coated High-Speed Steel | 3 | Aluminum, Brass, Plastic, Wood | 0000000 | 00000 | 0000000 | 0000 | 0000 |
| 5/8" | 3/16" | 3 1/4" | 1.3" | Hex | 1/4" | Titanium Nitride (TiN) Coated High-Speed Steel | 3 | Aluminum, Brass, Plastic, Wood | 0000000 | 00000 | 0000000 | 0000 | 0000 |
| 5/8" | 1/4" | 3 21/32" | 2.7" | Hex | 1/4" | Titanium Nitride (TiN) Coated High-Speed Steel | 3 | Aluminum, Brass, Plastic, Wood | 00000000 | 00000 | 0000000 | 0000 | 0000 |
| 3/4" | 3/16" | 3 1/4" | 1.3" | Hex | 1/4" | Titanium Nitride (TiN) Coated High-Speed Steel | 3 | Aluminum, Brass, Plastic, Wood | 0000000 | 00000 | 0000000 | 0000 | 0000 |
| 3/4" | 1/4" | 3 5/8" | 1.6" | Hex | 1/4" | Titanium Nitride (TiN) Coated High-Speed Steel | 3 | Aluminum, Brass, Plastic, Wood | 0000000 | 00000 | 0000000 | 0000 | 0000 |
| Each | 1-2 | 3-Up | |||||||||||
| 3/4" | 5/16" | 3 31/32" | 3" | Hex | 1/4" | Titanium Nitride (TiN) Coated High-Speed Steel | 3 | Aluminum, Brass, Plastic, Wood | 00000000 | 00000 | 0000000 | 0000 | 0000 |
| 1" | 7/16" | 4 11/16" | 3.7" | Hex | 1/4" | Titanium Nitride (TiN) Coated High-Speed Steel | 3 | Aluminum, Brass, Plastic, Wood | 00000000 | 00000 | 0000000 | 00000 | 00000 |
| Optional Rotating Depth Stop for 3/8", 1/2" Body Dia. Counterbores | 0000000 | Each | 000000 |
Drill-Bit Counterbores
Attach one of these counterbores to a standard jobbers’ or brad-point drill bit (sold separately) to convert it into a counterboring drill bit. Lock the counterbore into position on the drill bit with the two set screws.
Optional collar (not included) controls the cutting depth of your counterbore. It attaches with two set screws.
For technical drawings and 3-D models, click on a part number.
Counterbores | Optional Collars | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Body Dia. | For Drill Bit Size | Overall Lg. | Number of Flutes | For Use On | Each | OD | Wd. | Each | ||
Uncoated Steel | ||||||||||
| 5/8" | 1/4" | 1" | 4 | Plastic, Wood | 0000000 | 000000 | 7/8" | 1/4" | 0000000 | 00000 |
| 5/8" | 3/16" | 1" | 4 | Plastic, Wood | 0000000 | 00000 | 7/8" | 1/4" | 0000000 | 0000 |
| 3/4" | 1/4" | 1" | 4 | Plastic, Wood | 0000000 | 00000 | 1" | 1/4" | 0000000 | 0000 |
| 3/4" | 5/16" | 1 1/8" | 4 | Plastic, Wood | 0000000 | 00000 | 1" | 1/4" | 0000000 | 0000 |
| 7/8" | 3/8" | 1 1/4" | 4 | Plastic, Wood | 0000000 | 00000 | 1 1/8" | 1/4" | 0000000 | 0000 |
| 1" | 7/16" | 1 3/8" | 4 | Plastic, Wood | 0000000 | 00000 | 1 1/4" | 5/16" | 0000000 | 0000 |
| 1 1/8" | 1/2" | 1 1/2" | 4 | Plastic, Wood | 0000000 | 00000 | 1 3/8" | 5/16" | 0000000 | 0000 |
| 1 1/4" | 9/16" | 1 5/8" | 4 | Plastic, Wood | 0000000 | 00000 | 1 1/2" | 3/8" | 0000000 | 0000 |
Drill-Bit Counterbore Sets
Convert standard jobbers’ or brad-point drill bits into counterboring drill bits for drilling and counterboring in one step.
For technical drawings and 3-D models, click on a part number.
| Sizes Included | Number of Pieces | For Use On | Container Type | Each | |
Uncoated Steel | |||||
|---|---|---|---|---|---|
| 3/16", 1/4", 5/16", 3/8", 7/16", 1/2" | 6 | Plastic, Wood | Wood Stand | 0000000 | 0000000 |
Inch Size Drill-Point Counterbore Sets
Keep counterbores in various sizes on hand to drill and counterbore holes with enough clearance for socket head cap screws without changing tools. The longer the counterbore, the thicker the material it can drill.
Diameter | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sizes Included | Overall Length | Number of Pieces | Body | Shank | Drill Tip | Maximum Hole Drilling Depth | Number of Flutes | Shank Type | For Use On | Container Type | Each | |
Uncoated High-Speed Steel | ||||||||||||
| No. 5 No. 6 No. 8 No. 10 1/4" 5/16" 3/8" 7/16" 1/2" | 1 7/32" 1 7/32" 1 15/32" 1 1/2" 1 3/4" 1 15/16" 2 11/32" 2 1/2" 2 11/16" | 9 | 0.22" 0.242" 0.29" 0.332" 0.406" 0.49" 0.593" 0.687" 0.781" | 1/4" 1/4" 5/16" 5/16" 7/16" 1/2" 5/8" 5/8" 5/8" | 0.138" 0.15" 0.178" 0.2" 0.28" 0.34" 0.406" 0.468" 0.532" | 1/4" 1/4" 0.281" 0.312" 3/8" 3/8" 0.468" 1/2" 0.562" | 2 | Round | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | Plastic Case | 00000000 | 0000000 |
| No. 5 No. 6 No. 8 No. 10 1/4" 5/16" 3/8" 7/16" 1/2" | 2" 2" 2 1/4" 2 1/4" 2 3/4" 3" 3 1/2" 4" 4 1/2" | 9 | 0.22" 0.242" 0.29" 0.332" 0.406" 0.49" 0.593" 0.687" 0.781" | 1/4" 1/4" 3/8" 3/8" 3/8" 1/2" 1/2" 1/2" 1/2" | 0.138" 0.15" 0.178" 0.2" 0.28" 0.34" 0.406" 0.468" 0.532" | 0.414" 0.45" 0.534" 0.6" 0.84" 1.02" 1.218" 1.404" 1.596" | 2 | Round | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | Plastic Case | 00000000 | 000000 |
Metric Size Drill-Point Counterbore Sets
No need for separate tools, these sets have counterbores in various sizes that drill and counterbore holes with enough clearance for socket head cap screws. The longer the counterbore, the thicker the material it can drill.
Diameter | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sizes Included | Number of Pieces | Body | Shank | Drill Tip | Overall Length | Maximum Hole Drilling Depth | Number of Flutes | Shank Type | For Use On | Container Type | Each | |
Uncoated High-Speed Steel | ||||||||||||
| 3 mm 4 mm 5 mm 6 mm 8 mm 10 mm 12 mm 14 mm 16 mm | 9 | 5.95 mm 7.54 mm 9.13 mm 10.71 mm 13.49 mm 16.66 mm 18.75 mm 21.82 mm 24.6 mm | 1/4" 1/4" 5/16" 5/16" 7/16" 1/2" 5/8" 5/8" 5/8" | 3.57 mm 4.36 mm 5.55 mm 6.35 mm 8.73 mm 10.32 mm 12.7 mm 14.68 mm 16.67 mm | 1 9/32" 1 13/32" 1 9/16" 1 5/8" 1 29/32" 2 5/32" 2 9/16" 2 27/32" 3 1/2" | 6.35 mm 7.54 mm 7.94 mm 9.52 mm 11.11 mm 14.29 mm 15.87 mm 16.67 mm 17.46 mm | 2 | Round | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | Plastic Case | 00000000 | 0000000 |