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 |
| No. 5 | 0.205" | 3/16" | 1/8" | 0.188" | 4 1/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| No. 6 | 0.228" | 7/32" | 0.138" | 0.219" | 4 5/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| No. 8 | 0.272" | 1/4" | 0.164" | 0.250" | 5" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| No. 10 | 0.314" | 9/32" | 0.19" | 0.281" | 5 1/4" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| 1/4" | 0.382" | 5/16" | 1/4" | 0.313" | 5 5/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| 5/16" | 0.475" | 3/8" | 5/16" | 0.375" | 6 1/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| 3/8" | 0.572" | 1/2" | 3/8" | 0.500" | 6 1/2" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| 7/16" | 0.663" | 1/2" | 7/16" | 0.500" | 7" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| 1/2" | 0.757" | 1/2" | 1/2" | 0.500" | 7 1/2" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| 5/8" | 0.945" | 5/8" | 5/8" | 0.625" | 7 5/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 000000 |
| 3/4" | 1.133" | 3/4" | 3/4" | 0.750" | 7 3/4" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 000000 |
| 7/8" | 1.322" | 7/8" | 7/8" | 0.875" | 8 1/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 000000 |
| 1" | 1.510" | 1" | 1" | 1.000" | 8 1/2" | 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 |
| No. 5 | 0.205" | 3/16" | 1/8" | 0.188" | 4 1/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| No. 6 | 0.228" | 7/32" | 0.138" | 0.219" | 4 5/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| No. 8 | 0.272" | 1/4" | 0.164" | 0.250" | 5" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| No. 10 | 0.314" | 9/32" | 0.19" | 0.281" | 5 1/4" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| 1/4" | 0.382" | 5/16" | 1/4" | 0.313" | 5 5/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| 5/16" | 0.475" | 3/8" | 5/16" | 0.375" | 6 1/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| 3/8" | 0.572" | 1/2" | 3/8" | 0.500" | 6 1/2" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| 7/16" | 0.663" | 1/2" | 7/16" | 0.500" | 7" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 000000 |
| 1/2" | 0.757" | 1/2" | 1/2" | 0.500" | 7 1/2" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 000000 |
| 5/8" | 0.945" | 5/8" | 5/8" | 0.625" | 7 5/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 000000 |
| 3/4" | 1.133" | 3/4" | 3/4" | 0.750" | 7 3/4" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 000000 |
| 7/8" | 1.322" | 7/8" | 7/8" | 0.875" | 8 1/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 000000 |
| 1" | 1.510" | 1" | 1" | 1.000" | 8 1/2" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 000000 |
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 |
| No. 5 | 0.221" | 3/16" | 0.141" | 0.188" | 4 1/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| No. 6 | 0.244" | 7/32" | 0.154" | 0.219" | 4 5/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| No. 8 | 0.288" | 1/4" | 0.18" | 0.250" | 5" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| No. 10 | 0.330" | 9/32" | 0.206" | 0.281" | 5 1/4" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| 1/4" | 0.398" | 5/16" | 0.266" | 0.313" | 5 5/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| 5/16" | 0.491" | 3/8" | 0.328" | 0.375" | 6 1/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| 3/8" | 0.588" | 1/2" | 0.391" | 0.500" | 6 1/2" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| 7/16" | 0.679" | 1/2" | 0.453" | 0.500" | 7" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| 1/2" | 0.773" | 1/2" | 0.515" | 0.500" | 7 1/2" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| 5/8" | 0.961" | 5/8" | 0.641" | 0.625" | 7 5/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 000000 |
| 3/4" | 1.149" | 3/4" | 0.766" | 0.750" | 7 3/4" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 000000 |
| 7/8" | 1.338" | 7/8" | 0.891" | 0.875" | 8 1/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 000000 |
| 1" | 1.526" | 1" | 1.016" | 1.000" | 8 1/2" | 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 |
| No. 5 | 0.236" | 3/16" | 0.156" | 0.188" | 4 1/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| No. 6 | 0.259" | 7/32" | 0.169" | 0.219" | 4 5/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| No. 8 | 0.303" | 1/4" | 0.195" | 0.250" | 5" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| No. 10 | 0.345" | 9/32" | 0.221" | 0.281" | 5 1/4" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| 1/4" | 0.413" | 5/16" | 0.281" | 0.313" | 5 5/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| 5/16" | 0.506" | 3/8" | 0.344" | 0.375" | 6 1/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| 3/8" | 0.603" | 1/2" | 0.406" | 0.500" | 6 1/2" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| 7/16" | 0.694" | 1/2" | 0.469" | 0.500" | 7" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| 1/2" | 0.788" | 1/2" | 0.531" | 0.500" | 7 1/2" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| 5/8" | 0.976" | 5/8" | 0.656" | 0.625" | 7 5/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 000000 |
| 3/4" | 1.164" | 3/4" | 0.781" | 0.750" | 7 3/4" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 000000 |
| 7/8" | 1.353" | 7/8" | 0.906" | 0.875" | 8 1/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 000000 |
| 1" | 1.541" | 1" | 1.031" | 1.000" | 8 1/2" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 000000 |
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 |
| No. 5 | 0.221" | 3/16" | 0.141" | 0.188" | 4 1/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| No. 6 | 0.244" | 7/32" | 0.154" | 0.219" | 4 5/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| No. 8 | 0.288" | 1/4" | 0.18" | 0.250" | 5" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| No. 10 | 0.330" | 9/32" | 0.206" | 0.281" | 5 1/4" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| 1/4" | 0.398" | 5/16" | 0.266" | 0.313" | 5 5/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| 5/16" | 0.491" | 3/8" | 0.328" | 0.375" | 6 1/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| 3/8" | 0.588" | 1/2" | 0.391" | 0.500" | 6 1/2" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| 7/16" | 0.679" | 1/2" | 0.453" | 0.500" | 7" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 000000 |
| 1/2" | 0.773" | 1/2" | 0.515" | 0.500" | 7 1/2" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 000000 |
| 5/8" | 0.961" | 5/8" | 0.641" | 0.625" | 7 5/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 000000 |
| 3/4" | 1.149" | 3/4" | 0.766" | 0.750" | 7 3/4" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 000000 |
| 7/8" | 1.338" | 7/8" | 0.891" | 0.875" | 8 1/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 000000 |
| 1" | 1.526" | 1" | 1.016" | 1.000" | 8 1/2" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 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 | 00000000 | 00000 |
| No. 5 | 0.236" | 3/16" | 0.156" | 0.188" | 4 1/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| No. 6 | 0.259" | 7/32" | 0.169" | 0.219" | 4 5/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| No. 8 | 0.303" | 1/4" | 0.195" | 0.250" | 5" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| No. 10 | 0.345" | 9/32" | 0.221" | 0.281" | 5 1/4" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| 1/4" | 0.413" | 5/16" | 0.281" | 0.313" | 5 5/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| 5/16" | 0.506" | 3/8" | 0.344" | 0.375" | 6 1/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| 3/8" | 0.603" | 1/2" | 0.406" | 0.500" | 6 1/2" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 00000 |
| 7/16" | 0.694" | 1/2" | 0.469" | 0.500" | 7" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 000000 |
| 1/2" | 0.788" | 1/2" | 0.531" | 0.500" | 7 1/2" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 000000 |
| 5/8" | 0.976" | 5/8" | 0.656" | 0.625" | 7 5/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 000000 |
| 3/4" | 1.164" | 3/4" | 0.781" | 0.750" | 7 3/4" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 000000 |
| 7/8" | 1.353" | 7/8" | 0.906" | 0.875" | 8 1/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 000000 |
| 1" | 1.541" | 1" | 1.031" | 1.000" | 8 1/2" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 00000000 | 000000 |
Metric Size High-Speed Steel Counterbores with Built-In Pilot
These counterbores are oversized for use with screw holes in misaligned sheets or layers of material. All have a built-in pilot to maintain alignment in the hole. The body diameter and pilot diameter account for the 0.5 mm oversized diameter rating.
For technical drawings and 3-D models, click on a part number.
Dia. | Lg. | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| For Screw Size, mm | Body, mm | Shank | Pilot | Overall | Number of Flutes | Flute Style | For Use On | Each | |
Uncoated High-Speed Steel | |||||||||
0.5 mm Oversized | |||||||||
| 3 | 6 | 3/16" | 0.219" | 4 1/2" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 000000 |
| 4 | 7.5 | 1/4" | 0.250" | 5" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| 5 | 9 | 5/16" | 0.281" | 5 5/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| 6 | 10.5 | 5/16" | 0.313" | 5 5/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| 8 | 13.5 | 1/2" | 0.375" | 6 1/2" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| 10 | 16.5 | 1/2" | 0.500" | 7" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| 12 | 18.5 | 1/2" | 0.500" | 7 1/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| 14 | 21.5 | 5/8" | 0.563" | 7 1/2" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 00000 |
| 16 | 24.5 | 5/8" | 0.625" | 7 5/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 000000 |
| 20 | 30.5 | 7/8" | 0.750" | 8 1/8" | 4 | Spiral | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 000000 |
Carbide-Tipped Counterbores with Built-In Pilot for Steel
To resist damage when cutting steel, these counterbores are C5 carbide-tipped alloy steel. The built-in pilot maintains alignment in the hole.
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 C5 Carbide-Tipped Alloy Steel | ||||||||||
| 1/4" | 0.382" | 5/16" | 1/4" | 0.313" | 5 5/8" | 3 | Spiral | Steel | 00000000 | 0000000 |
| 5/16" | 0.475" | 3/8" | 5/16" | 0.375" | 6 1/8" | 3 | Spiral | Steel | 00000000 | 000000 |
| 3/8" | 0.572" | 1/2" | 3/8" | 0.500" | 6 1/2" | 3 | Spiral | Steel | 00000000 | 000000 |
| 7/16" | 0.663" | 1/2" | 7/16" | 0.500" | 7" | 3 | Spiral | Steel | 00000000 | 000000 |
| 1/2" | 0.757" | 1/2" | 1/2" | 0.500" | 7 1/2" | 3 | Spiral | Steel | 00000000 | 000000 |
| 5/8" | 0.945" | 5/8" | 5/8" | 0.625" | 7 5/8" | 3 | Spiral | Steel | 00000000 | 000000 |
| 3/4" | 1.133" | 3/4" | 3/4" | 0.750" | 7 3/4" | 3 | Spiral | Steel | 00000000 | 000000 |
| 7/8" | 1.322" | 7/8" | 7/8" | 0.875" | 8 1/8" | 4 | Spiral | Steel | 00000000 | 000000 |
| 1" | 1.510" | 1" | 1" | 1.000" | 8 1/2" | 4 | Spiral | Steel | 00000000 | 000000 |
Oversized Carbide-Tipped Counterbores with Built-In Pilot for Steel
Counterbore screw holes in misaligned sheets or layers of material. These counterbores are C5 carbide-tipped alloy steel to resist damage when used with steel. They have a built-in pilot to maintain alignment in the hole. The body diameter and pilot diameter account for the 1/32” or 1/64” oversized diameter rating.
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 C5 Carbide-Tipped Alloy Steel | ||||||||||
1/64" Oversized | ||||||||||
| 1/4" | 0.398" | 5/16" | 17/64" | 0.313" | 5 5/8" | 3 | Spiral | Steel | 00000000 | 0000000 |
| 5/16" | 0.491" | 3/8" | 21/64" | 0.375" | 6 1/8" | 3 | Spiral | Steel | 00000000 | 000000 |
| 3/8" | 0.588" | 1/2" | 25/64" | 0.500" | 6 1/2" | 3 | Spiral | Steel | 00000000 | 000000 |
| 7/16" | 0.679" | 1/2" | 29/64" | 0.500" | 7" | 3 | Spiral | Steel | 00000000 | 000000 |
| 1/2" | 0.773" | 1/2" | 33/64" | 0.500" | 7 1/2" | 3 | Spiral | Steel | 00000000 | 000000 |
| 5/8" | 0.961" | 5/8" | 41/64" | 0.625" | 7 5/8" | 3 | Spiral | Steel | 00000000 | 000000 |
| 3/4" | 1.149" | 3/4" | 49/64" | 0.750" | 7 3/4" | 3 | Spiral | Steel | 00000000 | 000000 |
| 7/8" | 1.338" | 7/8" | 57/64" | 0.875" | 8 1/8" | 4 | Spiral | Steel | 00000000 | 000000 |
| 1" | 1.526" | 1" | 1 1/64" | 1.000" | 8 1/2" | 4 | Spiral | Steel | 00000000 | 000000 |
1/32" Oversized | ||||||||||
| 1/4" | 0.413" | 5/16" | 9/32" | 0.313" | 5 5/8" | 3 | Spiral | Steel | 00000000 | 000000 |
| 5/16" | 0.506" | 3/8" | 11/32" | 0.375" | 6 1/8" | 3 | Spiral | Steel | 00000000 | 000000 |
| 3/8" | 0.603" | 1/2" | 13/32" | 0.500" | 6 1/2" | 3 | Spiral | Steel | 00000000 | 000000 |
| 7/16" | 0.694" | 1/2" | 15/32" | 0.500" | 7" | 3 | Spiral | Steel | 00000000 | 000000 |
| 1/2" | 0.788" | 1/2" | 17/32" | 0.500" | 7 1/2" | 3 | Spiral | Steel | 00000000 | 000000 |
| 5/8" | 0.976" | 5/8" | 21/32" | 0.625" | 7 5/8" | 3 | Spiral | Steel | 00000000 | 000000 |
| 3/4" | 1.164" | 3/4" | 25/32" | 0.750" | 7 3/4" | 3 | Spiral | Steel | 00000000 | 000000 |
| 7/8" | 1.353" | 7/8" | 29/32" | 0.875" | 8 1/8" | 4 | Spiral | Steel | 00000000 | 000000 |
| 1" | 1.541" | 1" | 1 1/32" | 1.000" | 8 1/2" | 4 | Spiral | Steel | 00000000 | 000000 |
Oversized Carbide-Tipped Counterbores with Built-In
Pilot for Aluminum, Brass, Bronze, and Cast Iron
Use these counterbores with screw holes in misaligned sheets or layers of material. They are C2 carbide-tipped alloy steel for excellent performance on abrasive materials such as cast iron and nonferrous metals. 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.
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 C2 Carbide-Tipped Alloy Steel | ||||||||||
1/64" Oversized | ||||||||||
| 1/4" | 0.398" | 5/16" | 17/64" | 0.313" | 5 5/8" | 3 | Spiral | Aluminum, Brass, Bronze, Cast Iron | 00000000 | 0000000 |
| 5/16" | 0.491" | 3/8" | 21/64" | 0.375" | 6 1/8" | 3 | Spiral | Aluminum, Brass, Bronze, Cast Iron | 00000000 | 000000 |
| 3/8" | 0.588" | 1/2" | 25/64" | 0.500" | 6 1/2" | 3 | Spiral | Aluminum, Brass, Bronze, Cast Iron | 00000000 | 000000 |
| 7/16" | 0.679" | 1/2" | 29/64" | 0.500" | 7" | 3 | Spiral | Aluminum, Brass, Bronze, Cast Iron | 00000000 | 000000 |
| 1/2" | 0.773" | 1/2" | 33/64" | 0.500" | 7 1/2" | 3 | Spiral | Aluminum, Brass, Bronze, Cast Iron | 00000000 | 000000 |
| 5/8" | 0.961" | 5/8" | 41/64" | 0.625" | 7 5/8" | 3 | Spiral | Aluminum, Brass, Bronze, Cast Iron | 00000000 | 000000 |
| 3/4" | 1.149" | 3/4" | 49/64" | 0.750" | 7 3/4" | 3 | Spiral | Aluminum, Brass, Bronze, Cast Iron | 00000000 | 000000 |
| 7/8" | 1.338" | 7/8" | 57/64" | 0.875" | 8 1/8" | 4 | Spiral | Aluminum, Brass, Bronze, Cast Iron | 00000000 | 000000 |
| 1" | 1.526" | 1" | 1 1/64" | 1.000" | 8 1/2" | 4 | Spiral | Aluminum, Brass, Bronze, Cast Iron | 00000000 | 000000 |
1/32" Oversized | ||||||||||
| 1/4" | 0.413" | 5/16" | 9/32" | 0.313" | 5 5/8" | 3 | Spiral | Aluminum, Brass, Bronze, Cast Iron | 00000000 | 000000 |
| 5/16" | 0.506" | 3/8" | 11/32" | 0.375" | 6 1/8" | 3 | Spiral | Aluminum, Brass, Bronze, Cast Iron | 00000000 | 000000 |
| 3/8" | 0.603" | 1/2" | 13/32" | 0.500" | 6 1/2" | 3 | Spiral | Aluminum, Brass, Bronze, Cast Iron | 00000000 | 000000 |
| 7/16" | 0.694" | 1/2" | 15/32" | 0.500" | 7" | 3 | Spiral | Aluminum, Brass, Bronze, Cast Iron | 00000000 | 000000 |
| 1/2" | 0.788" | 1/2" | 17/32" | 0.500" | 7 1/2" | 3 | Spiral | Aluminum, Brass, Bronze, Cast Iron | 00000000 | 000000 |
| 5/8" | 0.976" | 5/8" | 21/32" | 0.625" | 7 5/8" | 3 | Spiral | Aluminum, Brass, Bronze, Cast Iron | 00000000 | 000000 |
| 3/4" | 1.164" | 3/4" | 25/32" | 0.750" | 7 3/4" | 3 | Spiral | Aluminum, Brass, Bronze, Cast Iron | 00000000 | 000000 |
| 7/8" | 1.353" | 7/8" | 29/32" | 0.875" | 8 1/8" | 4 | Spiral | Aluminum, Brass, Bronze, Cast Iron | 00000000 | 000000 |
| 1" | 1.541" | 1" | 1 1/32" | 1.000" | 8 1/2" | 4 | Spiral | Aluminum, Brass, Bronze, Cast Iron | 00000000 | 000000 |
Carbide-Tipped Counterbores with Built-In Pilot
for Aluminum, Brass, Bronze, and Cast Iron
C2 carbide-tipped alloy steel has excellent performance on abrasive materials such as cast iron and nonferrous metals. The built-in pilot maintains alignment in the hole.
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 C2 Carbide-Tipped Alloy Steel | ||||||||||
| 1/4" | 0.382" | 5/16" | 1/4" | 0.313" | 5 5/8" | 3 | Spiral | Aluminum, Brass, Bronze, Cast Iron | 00000000 | 0000000 |
| 5/16" | 0.475" | 3/8" | 5/16" | 0.375" | 6 1/8" | 3 | Spiral | Aluminum, Brass, Bronze, Cast Iron | 00000000 | 000000 |
| 3/8" | 0.572" | 1/2" | 3/8" | 0.500" | 6 1/2" | 3 | Spiral | Aluminum, Brass, Bronze, Cast Iron | 00000000 | 000000 |
| 7/16" | 0.663" | 1/2" | 7/16" | 0.500" | 7" | 3 | Spiral | Aluminum, Brass, Bronze, Cast Iron | 00000000 | 000000 |
| 1/2" | 0.757" | 1/2" | 1/2" | 0.500" | 7 1/2" | 3 | Spiral | Aluminum, Brass, Bronze, Cast Iron | 00000000 | 000000 |
| 5/8" | 0.945" | 5/8" | 5/8" | 0.625" | 7 5/8" | 3 | Spiral | Aluminum, Brass, Bronze, Cast Iron | 00000000 | 000000 |
| 3/4" | 1.133" | 3/4" | 3/4" | 0.750" | 7 3/4" | 3 | Spiral | Aluminum, Brass, Bronze, Cast Iron | 00000000 | 000000 |
| 7/8" | 1.322" | 7/8" | 7/8" | 0.875" | 8 1/8" | 4 | Spiral | Aluminum, Brass, Bronze, Cast Iron | 00000000 | 000000 |
| 1" | 1.510" | 1" | 1" | 1.000" | 8 1/2" | 4 | Spiral | Aluminum, Brass, Bronze, Cast Iron | 00000000 | 000000 |
Inch Size Counterbore Sets with Built-In Pilot
The built-in pilot maintains alignment in the hole.
| Sizes Included | Number of Pieces | Pilot Lg. | Number of Flutes | Flute Style | Shank Type | For Use On | Each | |
Uncoated High-Speed Steel | ||||||||
|---|---|---|---|---|---|---|---|---|
| No. 4, No. 5, No. 6, No. 8, No. 10, 1/4", 3/8", 5/16", 7/16", 1/2" | 10 | 0.156", 0.188", 0.219", 0.250", 0.281", 0.313", 0.375", 0.500" | 4 | Spiral | Round | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 0000000 |
Metric Size Counterbore Sets with Built-In Pilot
The counterbores in this set are oversized for counterboring screw holes in sheets or layers of material that are misaligned. All have a built-in pilot to maintain alignment in the hole.
| Dia. Rating | Sizes Included | Number of Pieces | Pilot Lg. | Number of Flutes | Flute Style | Shank Type | For Use On | Each | |
Uncoated High-Speed Steel | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| 0.5 mm Oversized | 3 mm, 4 mm, 5 mm, 6 mm, 8 mm, 10 mm, 12 mm, 14 mm | 8 | 0.218", 0.250", 0.281", 0.312", 0.375", 0.500", 0.562" | 4 | Spiral | Round | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 0000000 |
Oversized Counterbore Sets with Built-In Pilot
Use these oversized counterbore sets when the screw holes in sheets or layers of material are misaligned. They have a built-in pilot to maintain alignment in the hole.
| Dia. Rating | Sizes Included | Number of Pieces | Pilot Lg. | Number of Flutes | Flute Style | Shank Type | For Use On | Each | |
Uncoated High-Speed Steel | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| 1/64" Oversized | No. 4, No. 5, No. 6, No. 8, No. 10, 1/4", 5/16", 3/8", 7/16", 1/2" | 10 | 0.156", 0.188", 0.219", 0.250", 0.281", 0.313", 0.375", 0.500" | 4 | Spiral | Round | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 0000000 |
| 1/32" Oversized | No. 4, No. 5, No. 6, No. 8, No. 10, 1/4", 5/16", 3/8", 7/16", 1/2" | 10 | 0.156", 0.188", 0.219", 0.250", 0.281", 0.313", 0.375", 0.500" | 4 | Spiral | Round | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 0000000 | 000000 |