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About Counterbores
Create flat-bottomed holes, so your screw heads sit flush, recessed, or slightly raised.
Built-In-Pilot Counterbore Sets
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Create flat, close-fitting recesses for a range of screw-head sizes. The pilot centers and stabilizes the counterbore for an accurate cut and even surface on the first try.
High-Speed Steel—Durable and wear resistant, these counterbores make accurate cuts in most materials without chipping or cracking.
For Screw Size | No. of Pieces | Shank Type | No. of Flutes | Each | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Uncoated High-Speed Steel | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
No. 4, No. 5, No. 6, No. 8, No. 10, 1/4", 5/16", 3/8", 7/16", 1/2" | 10 | Round | 4 | 2919A12 | 0000000 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Built-In-Pilot Counterbores
The pilot centers the counterbore and prevents wobbling for an accurate cut on the first try. With dimensions that match standard screw-head diameters and thread diameters, this is your plug-and-play option for pilot-driven counterbores.
High-Speed Steel
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Durable and wear resistant, these counterbores make accurate cuts in most materials without chipping or cracking.
Titanium Nitride (TiN) Coated—Withstand heat, corrosion, and abrasion for longer than uncoated counterbores, so the cutting edges stay sharper.
Carbide-Tipped Steel
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The hardest and most wear-resistant counterbores we offer. These bits stay sharper at higher temperatures and faster speeds for the best performance on hard and abrasive materials.
C2 Carbide—Hard enough to cut cleanly through cast iron and nonferrous metals.
C5 Carbide—Harder than C2 Carbide, these counterbores cut steel without damaging themselves or the hole.
Drill-Point Counterbore Sets
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Skip a step when installing screws of various thread diameters in metal. With a sharp point on the tip, these counterbores drill a pilot hole topped with a flat recess for the screw head. That's faster and more accurate than switching to a counterbore in between passes with your drill bit.
High-Speed Steel—Durable and wear resistant, these counterbores make accurate cuts in most materials without chipping or cracking.
Oversized Counterbores
Designed to give screw heads a slightly loose fit, these counterbores are a bit wider than standard sizes. The extra clearance prevents binding and leaves room for a seal or O-ring around the screw head.
High-Speed Steel
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Durable and wear resistant, these counterbores make accurate cuts in most materials without chipping or cracking.
Titanium Nitride (TiN) Coated—Withstand heat, corrosion, and abrasion for longer than uncoated counterbores, so the cutting edges stay sharper.
Carbide-Tipped Steel
![]() |
The hardest and most wear-resistant counterbores we offer. These bits stay sharper at higher temperatures and faster speeds for the best performance on hard and abrasive materials.
C2 Carbide—Hard enough to cut cleanly through cast iron and nonferrous metals.
C5 Carbide—Harder than C2 Carbide, these counterbores cut steel without damaging themselves or the hole.
Pilot | Shank | Uncoated | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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For Screw Size | Body Dia. | Dia. | Lg. | Overall Lg. | Dia. | Type | No. of Flutes | Each | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
C2 Carbide | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1/64" Oversize | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
3/8" | 0.588" | 25/64" | 0.500" | 6 1/2" | 1/2" | Round | 3 | 3218A133 | 0000000 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1/32" Oversize | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
3/8" | 0.603" | 13/32" | 0.500" | 6 1/2" | 1/2" | Round | 3 | 3218A132 | 000000 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
C5 Carbide | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1/64" Oversize | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
3/8" | 0.588" | 25/64" | 0.500" | 6 1/2" | 1/2" | Round | 3 | 3218A233 | 000000 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1/32" Oversize | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
3/8" | 0.603" | 13/32" | 0.500" | 6 1/2" | 1/2" | Round | 3 | 3218A232 | 000000 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Drill-Point Counterbores
Skip a step when installing screws in metal. With a sharp point on the tip, these counterbores drill a pilot hole topped with a flat recess for the screw head. That's faster and more accurate than switching to a counterbore in between passes with your drill bit.
High-Speed Steel
Oversized Counterbore Sets
![]() |
Designed to give screw heads a slightly loose fit, these counterbores are a bit wider than standard sizes. The extra clearance prevents binding and leaves room for a seal or O-ring around the screw head.
High-Speed Steel—Durable and wear resistant, these counterbores make accurate cuts in most materials without chipping or cracking.
Oversized Long-Life Counterbore Drill Bits
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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 counterbore 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.
Dia. | Lg. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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For Screw Size | Body | Step | Step | Overall | No. of Flutes | Point Angle | For Use On | Each | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Uncoated High-Speed Steel | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1/64" Oversize | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
3/8" | 0.578" | 0.391" | 3/4" | 4 1/8" | 2 | 118° | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 29525A63 | 000000 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1/32" Oversize | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
3/8" | 0.594" | 0.406" | 3/4" | 4 1/8" | 2 | 118° | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 29525A64 | 00000 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Counterbore Drill Bits
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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.
Dia. | Lg. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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For Screw Size | Body | Step | Step | Overall | Point Angle | For Use On | Each | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Uncoated High-Speed Steel | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
3/8" | 0.594" | 0.406" | 7/8" | 7 1/8" | 118° | Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel | 8914A36 | 000000 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||