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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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 |