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Fluteless Smooth-Finish Countersinks with Pilot for Screws
High-Speed Steel
 |
0 Flutes |
These versatile, wear-resistant countersinks cut cleanly in most materials, including plastic, aluminum, and steel.
Manufacturer—We source from trusted manufacturers who vet raw materials for purity and use diamond grinding wheels to machine precise edges. This keeps cutting surfaces smooth and free of microscopic burrs. Because our suppliers clean their wheels more often than other manufacturers, each countersink is consistently ground to create uniform holes every time.
Dia. | Pilot | Uncoated | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
For Hole Dia. | Body | Shank | Dia. | Lg. | For Screw Size | Overall Lg. | Shank Type | Mfr. | Each | |||
0 Flutes | ||||||||||||
82° Countersink Angle | ||||||||||||
| 1/4" to 33/64" | 33/64" | 3/8" | 1/4" | 5/32" | 1/4" | 2" | Round | Republic Drill | 2739A64 | 000000 | ||
| 5/16" to 41/64" | 41/64" | 3/8" | 5/16" | 5/32" | 5/16" | 2 3/16" | Round | Republic Drill | 2739A66 | 00000 | ||
| 3/8" to 49/64" | 49/64" | 1/2" | 3/8" | 5/32" | 3/8" | 2 1/2" | Round | Republic Drill | 2739A68 | 00000 | ||
| 7/16" to 53/64" | 53/64" | 1/2" | 7/16" | 7/32" | 7/16" | 2 11/16" | Round | Republic Drill | 2739A71 | 00000 | ||
| 1/2" to 15/16" | 15/16" | 1/2" | 1/2" | 1/4" | 1/2" | 2 11/16" | Round | Republic Drill | 2739A73 | 00000 | ||
Center Drill Sets
 |
82° Countersink Angle | 90° Countersink Angle | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
No. of Pieces | Trade Size | Finish | Container Type | Mfr. | Each | Each | ||||
High-Speed Steel | ||||||||||
| 5 | 1, 2, 3, 4, 5 | Uncoated | Plastic Case | Dormer Pramet | 2917A2 | 000000 | 2917A3 | 000000 | ||
Carbide | ||||||||||
| 6 | 1, 2, 3, 4, 5, 6 | Uncoated | Metal Case | Ultra Tool | 2925A72 | 000000 | 2925A73 | 000000 | ||
| 6 | 1, 2, 3, 4, 5, 6 | Titanium Carbon Nitride (TiCN) Coated | Metal Case | Ultra Tool | 2936A321 | 000000 | 2936A331 | 000000 | ||
| 6 | 1, 2, 3, 4, 5, 6 | Titanium Aluminum Nitride (TiAlN) Coated | Metal Case | Ultra Tool | 2936A322 | 000000 | 2936A332 | 000000 | ||
| 6 | 1, 2, 3, 4, 5, 6 | Aluminum Titanium Nitride (AlTiN) Coated | Metal Case | Ultra Tool | 2936A323 | 000000 | 2936A333 | 000000 | ||
Oversized Counterbores
High-Speed Steel
 |
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.
Pilot | Shank | Uncoated | Titanium Nitride (TiN) Coated | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
For Screw Size | Body Dia. | Dia. | Lg. | Overall Lg. | Dia. | Type | No. of Flutes | Mfr. | Each | Each | ||||
1/64" Oversize | ||||||||||||||
| No. 4 | 0.206" | 0.128" | 0.156" | 3 7/8" | 5/32" | Round | 4 | Alvord-Polk Tool | 2919A51 | 000000 | 28225A51 | 000000 | ||
| No. 5 | 0.221" | 0.141" | 0.188" | 4 1/8" | 3/16" | Round | 4 | Alvord-Polk Tool | 2919A52 | 00000 | 28225A52 | 00000 | ||
| No. 6 | 0.244" | 0.154" | 0.219" | 4 5/8" | 7/32" | Round | 4 | Alvord-Polk Tool | 2919A53 | 00000 | 28225A53 | 00000 | ||
| No. 8 | 0.288" | 0.18" | 0.250" | 5" | 1/4" | Round | 4 | Alvord-Polk Tool | 2919A54 | 00000 | 28225A54 | 00000 | ||
| No. 10 | 0.330" | 0.206" | 0.281" | 5 1/4" | 9/32" | Round | 4 | Alvord-Polk Tool | 2919A55 | 00000 | 28225A55 | 00000 | ||
| 1/4" | 0.398" | 0.266" | 0.313" | 5 5/8" | 5/16" | Round | 4 | Alvord-Polk Tool | 2919A56 | 00000 | 28225A56 | 00000 | ||
| 5/16" | 0.491" | 0.328" | 0.375" | 6 1/8" | 3/8" | Round | 4 | Alvord-Polk Tool | 2919A57 | 00000 | 28225A57 | 00000 | ||
| 3/8" | 0.588" | 0.391" | 0.500" | 6 1/2" | 1/2" | Round | 4 | Alvord-Polk Tool | 2919A58 | 00000 | 28225A58 | 00000 | ||
| 7/16" | 0.679" | 0.453" | 0.500" | 7" | 1/2" | Round | 4 | Alvord-Polk Tool | 2919A59 | 00000 | 28225A59 | 000000 | ||
| 1/2" | 0.773" | 0.515" | 0.500" | 7 1/2" | 1/2" | Round | 4 | Alvord-Polk Tool | 2919A61 | 00000 | 28225A61 | 000000 | ||
| 5/8" | 0.961" | 0.641" | 0.625" | 7 5/8" | 5/8" | Round | 4 | Alvord-Polk Tool | 2919A62 | 000000 | 28225A62 | 000000 | ||
| 3/4" | 1.149" | 0.766" | 0.750" | 7 3/4" | 3/4" | Round | 4 | Alvord-Polk Tool | 2919A63 | 000000 | 28225A63 | 000000 | ||
| 7/8" | 1.338" | 0.891" | 0.875" | 8 1/8" | 7/8" | Round | 4 | Alvord-Polk Tool | 2919A67 | 000000 | 28225A64 | 000000 | ||
| 1" | 1.526" | 1.016" | 1.000" | 8 1/2" | 1" | Round | 4 | Alvord-Polk Tool | 2919A65 | 000000 | 28225A65 | 000000 | ||
1/32" Oversize | ||||||||||||||
| No. 4 | 0.221" | 0.143" | 0.156" | 3 7/8" | 5/32" | Round | 4 | Alvord-Polk Tool | 2919A71 | 00000 | 28225A71 | 00000 | ||
| No. 5 | 0.236" | 0.156" | 0.188" | 4 1/8" | 3/16" | Round | 4 | Alvord-Polk Tool | 2919A72 | 00000 | 28225A72 | 00000 | ||
| No. 6 | 0.259" | 0.169" | 0.219" | 4 5/8" | 7/32" | Round | 4 | Alvord-Polk Tool | 2919A73 | 00000 | 28225A73 | 00000 | ||
| No. 8 | 0.303" | 0.195" | 0.250" | 5" | 1/4" | Round | 4 | Alvord-Polk Tool | 2919A74 | 00000 | 28225A74 | 00000 | ||
| No. 10 | 0.345" | 0.221" | 0.281" | 5 1/4" | 9/32" | Round | 4 | Alvord-Polk Tool | 2919A75 | 00000 | 28225A75 | 00000 | ||
| 1/4" | 0.413" | 0.281" | 0.313" | 5 5/8" | 5/16" | Round | 4 | Alvord-Polk Tool | 2919A76 | 00000 | 28225A76 | 00000 | ||
| 5/16" | 0.506" | 0.344" | 0.375" | 6 1/8" | 3/8" | Round | 4 | Alvord-Polk Tool | 2919A77 | 00000 | 28225A77 | 00000 | ||
| 3/8" | 0.603" | 0.406" | 0.500" | 6 1/2" | 1/2" | Round | 4 | Alvord-Polk Tool | 2919A78 | 00000 | 28225A78 | 00000 | ||
| 7/16" | 0.694" | 0.469" | 0.500" | 7" | 1/2" | Round | 4 | Alvord-Polk Tool | 2919A79 | 00000 | 28225A79 | 000000 | ||
| 1/2" | 0.788" | 0.531" | 0.500" | 7 1/2" | 1/2" | Round | 4 | Alvord-Polk Tool | 2919A81 | 00000 | 28225A81 | 000000 | ||
| 5/8" | 0.976" | 0.656" | 0.625" | 7 5/8" | 5/8" | Round | 4 | Alvord-Polk Tool | 2919A82 | 000000 | 28225A82 | 000000 | ||
| 3/4" | 1.164" | 0.781" | 0.750" | 7 3/4" | 3/4" | Round | 4 | Alvord-Polk Tool | 2919A83 | 000000 | 28225A83 | 000000 | ||
| 7/8" | 1.353" | 0.906" | 0.875" | 8 1/8" | 7/8" | Round | 4 | Alvord-Polk Tool | 2919A87 | 000000 | 28225A84 | 000000 | ||
| 1" | 1.541" | 1.031" | 1.000" | 8 1/2" | 1" | Round | 4 | Alvord-Polk Tool | 2919A85 | 000000 | 28225A85 | 000000 | ||
0.5 mm Oversize | ||||||||||||||
| M3 | 6.0 mm | 3.5 mm | 0.219" | 4 1/2" | 3/16" | Round | 4 | Alvord-Polk Tool | 2740A11 | 00000 | ——— | 0 | ||
| M4 | 7.5 mm | 4.5 mm | 0.250" | 5" | 1/4" | Round | 4 | Alvord-Polk Tool | 2740A12 | 00000 | ——— | 0 | ||
| M5 | 9.0 mm | 5.5 mm | 0.281" | 5 5/8" | 5/16" | Round | 4 | Alvord-Polk Tool | 2740A13 | 00000 | ——— | 0 | ||
| M6 | 10.5 mm | 6.5 mm | 0.313" | 5 5/8" | 5/16" | Round | 4 | Alvord-Polk Tool | 2740A14 | 00000 | ——— | 0 | ||
| M8 | 13.5 mm | 8.5 mm | 0.375" | 6 1/2" | 1/2" | Round | 4 | Alvord-Polk Tool | 2740A15 | 00000 | ——— | 0 | ||
| M10 | 16.5 mm | 10.5 mm | 0.500" | 7" | 1/2" | Round | 4 | Alvord-Polk Tool | 2740A16 | 00000 | ——— | 0 | ||
| M12 | 18.5 mm | 12.5 mm | 0.500" | 7 1/8" | 1/2" | Round | 4 | Alvord-Polk Tool | 2740A17 | 00000 | ——— | 0 | ||
| M14 | 21.5 mm | 14.5 mm | 0.563" | 7 1/2" | 5/8" | Round | 4 | Alvord-Polk Tool | 2740A18 | 000000 | ——— | 0 | ||
| M16 | 24.5 mm | 16.5 mm | 0.625" | 7 5/8" | 5/8" | Round | 4 | Alvord-Polk Tool | 2740A22 | 000000 | ——— | 0 | ||
| M20 | 30.5 mm | 20.5 mm | 0.750" | 8 1/8" | 7/8" | Round | 4 | Alvord-Polk Tool | 2740A26 | 000000 | ——— | 0 | ||
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 | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
For Screw Size | Body Dia. | Dia. | Lg. | Overall Lg. | Dia. | Type | No. of Flutes | Mfr. | Each | |||
C2 Carbide | ||||||||||||
1/64" Oversize | ||||||||||||
| 1/4" | 0.398" | 17/64" | 0.313" | 5 5/8" | 5/16" | Round | 3 | Rock River Tool | 3218A113 | 0000000 | ||
| 5/16" | 0.491" | 21/64" | 0.375" | 6 1/8" | 3/8" | Round | 3 | Rock River Tool | 3218A123 | 000000 | ||
| 3/8" | 0.588" | 25/64" | 0.500" | 6 1/2" | 1/2" | Round | 3 | Rock River Tool | 3218A133 | 000000 | ||
| 7/16" | 0.679" | 29/64" | 0.500" | 7" | 1/2" | Round | 3 | Rock River Tool | 3218A143 | 000000 | ||
| 1/2" | 0.773" | 33/64" | 0.500" | 7 1/2" | 1/2" | Round | 3 | Rock River Tool | 3218A153 | 000000 | ||
| 5/8" | 0.961" | 41/64" | 0.625" | 7 5/8" | 5/8" | Round | 3 | Rock River Tool | 3218A163 | 000000 | ||
| 3/4" | 1.149" | 49/64" | 0.750" | 7 3/4" | 3/4" | Round | 3 | Rock River Tool | 3218A173 | 000000 | ||
| 7/8" | 1.338" | 57/64" | 0.875" | 8 1/8" | 7/8" | Round | 4 | Rock River Tool | 3218A183 | 000000 | ||
| 1" | 1.526" | 1 1/64" | 1.000" | 8 1/2" | 1" | Round | 4 | Rock River Tool | 3218A193 | 000000 | ||
1/32" Oversize | ||||||||||||
| 1/4" | 0.413" | 9/32" | 0.313" | 5 5/8" | 5/16" | Round | 3 | Rock River Tool | 3218A112 | 000000 | ||
| 5/16" | 0.506" | 11/32" | 0.375" | 6 1/8" | 3/8" | Round | 3 | Rock River Tool | 3218A122 | 000000 | ||
| 3/8" | 0.603" | 13/32" | 0.500" | 6 1/2" | 1/2" | Round | 3 | Rock River Tool | 3218A132 | 000000 | ||
| 7/16" | 0.694" | 15/32" | 0.500" | 7" | 1/2" | Round | 3 | Rock River Tool | 3218A142 | 000000 | ||
| 1/2" | 0.788" | 17/32" | 0.500" | 7 1/2" | 1/2" | Round | 3 | Rock River Tool | 3218A152 | 000000 | ||
| 5/8" | 0.976" | 21/32" | 0.625" | 7 5/8" | 5/8" | Round | 3 | Rock River Tool | 3218A162 | 000000 | ||
| 3/4" | 1.164" | 25/32" | 0.750" | 7 3/4" | 3/4" | Round | 3 | Rock River Tool | 3218A172 | 000000 | ||
| 7/8" | 1.353" | 29/32" | 0.875" | 8 1/8" | 7/8" | Round | 4 | Rock River Tool | 3218A182 | 000000 | ||
| 1" | 1.541" | 1 1/32" | 1.000" | 8 1/2" | 1" | Round | 4 | Rock River Tool | 3218A192 | 000000 | ||
C5 Carbide | ||||||||||||
1/64" Oversize | ||||||||||||
| 1/4" | 0.398" | 17/64" | 0.313" | 5 5/8" | 5/16" | Round | 3 | Rock River Tool | 3218A213 | 000000 | ||
| 5/16" | 0.491" | 21/64" | 0.375" | 6 1/8" | 3/8" | Round | 3 | Rock River Tool | 3218A223 | 000000 | ||
| 3/8" | 0.588" | 25/64" | 0.500" | 6 1/2" | 1/2" | Round | 3 | Rock River Tool | 3218A233 | 000000 | ||
| 7/16" | 0.679" | 29/64" | 0.500" | 7" | 1/2" | Round | 3 | Rock River Tool | 3218A243 | 000000 | ||
| 1/2" | 0.773" | 33/64" | 0.500" | 7 1/2" | 1/2" | Round | 3 | Rock River Tool | 3218A253 | 000000 | ||
| 5/8" | 0.961" | 41/64" | 0.625" | 7 5/8" | 5/8" | Round | 3 | Rock River Tool | 3218A263 | 000000 | ||
| 3/4" | 1.149" | 49/64" | 0.750" | 7 3/4" | 3/4" | Round | 3 | Rock River Tool | 3218A273 | 000000 | ||
| 7/8" | 1.338" | 57/64" | 0.875" | 8 1/8" | 7/8" | Round | 4 | Rock River Tool | 3218A283 | 000000 | ||
| 1" | 1.526" | 1 1/64" | 1.000" | 8 1/2" | 1" | Round | 4 | Rock River Tool | 3218A293 | 000000 | ||
1/32" Oversize | ||||||||||||
| 1/4" | 0.413" | 9/32" | 0.313" | 5 5/8" | 5/16" | Round | 3 | Rock River Tool | 3218A212 | 000000 | ||
| 5/16" | 0.506" | 11/32" | 0.375" | 6 1/8" | 3/8" | Round | 3 | Rock River Tool | 3218A222 | 000000 | ||
| 3/8" | 0.603" | 13/32" | 0.500" | 6 1/2" | 1/2" | Round | 3 | Rock River Tool | 3218A232 | 000000 | ||
| 7/16" | 0.694" | 15/32" | 0.500" | 7" | 1/2" | Round | 3 | Rock River Tool | 3218A242 | 000000 | ||
| 1/2" | 0.788" | 17/32" | 0.500" | 7 1/2" | 1/2" | Round | 3 | Rock River Tool | 3218A252 | 000000 | ||
| 5/8" | 0.976" | 21/32" | 0.625" | 7 5/8" | 5/8" | Round | 3 | Rock River Tool | 3218A262 | 000000 | ||
| 3/4" | 1.164" | 25/32" | 0.750" | 7 3/4" | 3/4" | Round | 3 | Rock River Tool | 3218A272 | 000000 | ||
| 7/8" | 1.353" | 29/32" | 0.875" | 8 1/8" | 7/8" | Round | 4 | Rock River Tool | 3218A282 | 000000 | ||
| 1" | 1.541" | 1 1/32" | 1.000" | 8 1/2" | 1" | Round | 4 | Rock River Tool | 3218A292 | 000000 | ||
Fluteless Smooth-Finish Countersink Sets with Pilot for Screws
 |
Cut a smooth, accurate seat for your screw head on the first pass. The built-in pilot centers the countersink while the hollow body prevents chip buildup, vibration, and wobbling.
High-Speed Steel—These versatile, wear-resistant countersinks cut cleanly in most materials, including plastic, aluminum, and steel.
Manufacturer—We source from trusted manufacturers who vet raw materials for purity and use diamond grinding wheels to machine precise edges. This keeps cutting surfaces smooth and free of microscopic burrs. Because our suppliers clean their wheels more often than other manufacturers, each countersink is consistently ground to create uniform holes every time.
82° Countersink Angle | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
No. of Flutes | No. of Pieces | For Hole Dia. | Finish | Shank Type | Container Type | Mfr. | Each | |||
High-Speed Steel | ||||||||||
| 0 | 5 | 1/4" to 15/16" | Uncoated | Round | Wood Stand | Republic Drill | 2739A29 | 0000000 | ||
Counterbores for High-Profile Rounded-Head Screws
High-Speed Steel
 |
Durable and wear resistant, these counterbores make accurate cuts in most materials without chipping or cracking.
Uncoated | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
For Screw Size | Body Dia. | Overall Lg. | Shank Type | No. of Flutes | Pilot Lg. | Mfr. | Each | |||
| No. 0 | 0.110" | 2 1/2" | Round | 2 | 0.110" | Republic Drill | 2909A22 | 000000 | ||
| No. 1 | 0.133" | 2 1/2" | Round | 2 | 0.170" | Republic Drill | 2909A23 | 00000 | ||
| No. 2 | 0.155" | 2 1/2" | Round | 2 | 0.120" | Republic Drill | 2909A13 | 00000 | ||
| No. 3 | 0.176" | 2 1/2" | Round | 2 | 0.120" | Republic Drill | 2909A14 | 00000 | ||
| No. 4 | 0.198" | 2 5/8" | Round | 2 | 0.170" | Republic Drill | 2909A15 | 00000 | ||
| No. 5 | 0.220" | 2 5/8" | Round | 2 | 0.220" | Republic Drill | 2909A16 | 00000 | ||
| No. 6 | 0.241" | 2 5/8" | Round | 2 | 0.230" | Republic Drill | 2909A17 | 00000 | ||
| No. 8 | 0.285" | 2 3/4" | Round | 2 | 0.120" | Republic Drill | 2909A18 | 00000 | ||
| No. 10 | 0.328" | 2 7/8" | Round | 2 | 0.190" | Republic Drill | 2909A19 | 00000 | ||
| No. 12 | 0.372" | 3" | Round | 2 | 0.250" | Republic Drill | 2909A21 | 00000 | ||
Built-in-Pilot Counterbores
High-Speed Steel
|
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.
Pilot | Shank | Uncoated | Titanium Nitride (TiN) Coated | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
For Screw Size | Body Dia. | Dia. | Lg. | Overall Lg. | Dia. | Type | No. of Flutes | Mfr. | Each | Each | ||||
| No. 4 | 0.186" | 0.112" | 0.156" | 3 7/8" | 5/32" | Round | 4 | Alvord-Polk Tool | 2919A31 | 000000 | 28225A31 | 000000 | ||
| No. 5 | 0.205" | 1/8" | 0.188" | 4 1/8" | 3/16" | Round | 4 | Alvord-Polk Tool | 2919A32 | 00000 | 28225A32 | 00000 | ||
| No. 6 | 0.228" | 0.138" | 0.219" | 4 5/8" | 7/32" | Round | 4 | Alvord-Polk Tool | 2919A33 | 00000 | 28225A33 | 00000 | ||
| No. 8 | 0.272" | 0.164" | 0.250" | 5" | 1/4" | Round | 4 | Alvord-Polk Tool | 2919A34 | 00000 | 28225A34 | 00000 | ||
| No. 10 | 0.314" | 0.19" | 0.281" | 5 1/4" | 9/32" | Round | 4 | Alvord-Polk Tool | 2919A35 | 00000 | 28225A35 | 00000 | ||
| 1/4" | 0.382" | 1/4" | 0.313" | 5 5/8" | 5/16" | Round | 4 | Alvord-Polk Tool | 2919A36 | 00000 | 28225A36 | 00000 | ||
| 5/16" | 0.475" | 5/16" | 0.375" | 6 1/8" | 3/8" | Round | 4 | Alvord-Polk Tool | 2919A37 | 00000 | 28225A37 | 00000 | ||
| 3/8" | 0.572" | 3/8" | 0.500" | 6 1/2" | 1/2" | Round | 4 | Alvord-Polk Tool | 2919A38 | 00000 | 28225A38 | 00000 | ||
| 7/16" | 0.663" | 7/16" | 0.500" | 7" | 1/2" | Round | 4 | Alvord-Polk Tool | 2919A39 | 00000 | 28225A39 | 000000 | ||
| 1/2" | 0.757" | 1/2" | 0.500" | 7 1/2" | 1/2" | Round | 4 | Alvord-Polk Tool | 2919A41 | 00000 | 28225A41 | 000000 | ||
| 5/8" | 0.945" | 5/8" | 0.625" | 7 5/8" | 5/8" | Round | 4 | Alvord-Polk Tool | 2919A42 | 000000 | 28225A42 | 000000 | ||
| 3/4" | 1.133" | 3/4" | 0.750" | 7 3/4" | 3/4" | Round | 4 | Alvord-Polk Tool | 2919A43 | 000000 | 28225A43 | 000000 | ||
| 7/8" | 1.322" | 7/8" | 0.875" | 8 1/8" | 7/8" | Round | 4 | Alvord-Polk Tool | 2919A47 | 000000 | 28225A44 | 000000 | ||
| 1" | 1.510" | 1" | 1.000" | 8 1/2" | 1" | Round | 4 | Alvord-Polk Tool | 2919A45 | 000000 | 28225A45 | 000000 | ||
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 | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
For Screw Size | Body Dia. | Dia. | Lg. | Overall Lg. | Dia. | Type | No. of Flutes | Mfr. | Each | |||
C2 Carbide | ||||||||||||
| 1/4" | 0.382" | 1/4" | 0.313" | 5 5/8" | 5/16" | Round | 3 | Rock River Tool | 3218A111 | 0000000 | ||
| 5/16" | 0.475" | 5/16" | 0.375" | 6 1/8" | 3/8" | Round | 3 | Rock River Tool | 3218A121 | 000000 | ||
| 3/8" | 0.572" | 3/8" | 0.500" | 6 1/2" | 1/2" | Round | 3 | Rock River Tool | 3218A131 | 000000 | ||
| 7/16" | 0.663" | 7/16" | 0.500" | 7" | 1/2" | Round | 3 | Rock River Tool | 3218A141 | 000000 | ||
| 1/2" | 0.757" | 1/2" | 0.500" | 7 1/2" | 1/2" | Round | 3 | Rock River Tool | 3218A151 | 000000 | ||
| 5/8" | 0.945" | 5/8" | 0.625" | 7 5/8" | 5/8" | Round | 3 | Rock River Tool | 3218A161 | 000000 | ||
| 3/4" | 1.133" | 3/4" | 0.750" | 7 3/4" | 3/4" | Round | 3 | Rock River Tool | 3218A171 | 000000 | ||
| 7/8" | 1.322" | 7/8" | 0.875" | 8 1/8" | 7/8" | Round | 4 | Rock River Tool | 3218A181 | 000000 | ||
| 1" | 1.510" | 1" | 1.000" | 8 1/2" | 1" | Round | 4 | Rock River Tool | 3218A191 | 000000 | ||
C5 Carbide | ||||||||||||
| 1/4" | 0.382" | 1/4" | 0.313" | 5 5/8" | 5/16" | Round | 3 | Rock River Tool | 3218A211 | 000000 | ||
| 5/16" | 0.475" | 5/16" | 0.375" | 6 1/8" | 3/8" | Round | 3 | Rock River Tool | 3218A221 | 000000 | ||
| 3/8" | 0.572" | 3/8" | 0.500" | 6 1/2" | 1/2" | Round | 3 | Rock River Tool | 3218A231 | 000000 | ||
| 7/16" | 0.663" | 7/16" | 0.500" | 7" | 1/2" | Round | 3 | Rock River Tool | 3218A241 | 000000 | ||
| 1/2" | 0.757" | 1/2" | 0.500" | 7 1/2" | 1/2" | Round | 3 | Rock River Tool | 3218A251 | 000000 | ||
| 5/8" | 0.945" | 5/8" | 0.625" | 7 5/8" | 5/8" | Round | 3 | Rock River Tool | 3218A261 | 000000 | ||
| 3/4" | 1.133" | 3/4" | 0.750" | 7 3/4" | 3/4" | Round | 3 | Rock River Tool | 3218A271 | 000000 | ||
| 7/8" | 1.322" | 7/8" | 0.875" | 8 1/8" | 7/8" | Round | 4 | Rock River Tool | 3218A281 | 000000 | ||
| 1" | 1.510" | 1" | 1.000" | 8 1/2" | 1" | Round | 4 | Rock River Tool | 3218A291 | 000000 | ||
Port Counterbores
Carbide-Tipped Steel
 |
MS33649 and SAE AS5202 |
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.
Shank | Uncoated | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
For Thread Size | Series No. | Overall Lg. | Dia. | Lg. | Type | No. of Flutes | Pilot Lg. | Mil. Spec. | Mfr. | Each | |||
SAE J1926/1, SAE J514 | |||||||||||||
| 3/8"-24 | SAE-3SS | 3 3/4" | 0.5000" | 2" | Round | 4 | 0.473" | MS16142 | Tosco Tool Specialty Company | 2144A21 | 0000000 | ||
| 7/16"-20 | SAE-4SS | 3 3/4" | 0.5000" | 2" | Round | 4 | 0.552" | MS16142 | Tosco Tool Specialty Company | 2144A22 | 000000 | ||
| 1/2"-20 | SAE-5SS | 4" | 0.7500" | 2 1/32" | Round | 4 | 0.552" | MS16142 | Tosco Tool Specialty Company | 2144A23 | 000000 | ||
| 9/16"-18 | SAE-6SS | 4" | 0.7500" | 2 1/32" | Round | 4 | 0.614" | MS16142 | Tosco Tool Specialty Company | 2144A24 | 000000 | ||
| 3/4"-16 | SAE-8SS | 4" | 0.7500" | 2 1/32" | Round | 4 | 0.696" | MS16142 | Tosco Tool Specialty Company | 2144A25 | 000000 | ||
SAE AS5202 | |||||||||||||
| 3/8"-24 | NB-3 | 5 1/16" | 0.4995" | 2" | Round | 4 | 0.598" | MS33649 | Tosco Tool Specialty Company | 2144A11 | 000000 | ||
| 7/16"-20 | NB-4 | 5 5/32" | 0.4995" | 2" | Round | 4 | 0.671" | MS33649 | Tosco Tool Specialty Company | 2144A12 | 000000 | ||
| 1/2"-20 | NB-5 | 5 5/32" | 0.4995" | 2" | Round | 4 | 0.671" | MS33649 | Tosco Tool Specialty Company | 2144A13 | 000000 | ||
| 9/16"-18 | NB-6 | 5 3/16" | 0.4995" | 2" | Round | 4 | 0.724" | MS33649 | Tosco Tool Specialty Company | 2144A14 | 000000 | ||
| 3/4"-16 | NB-8 | 5 5/16" | 0.4995" | 2" | Round | 4 | 0.849" | MS33649 | Tosco Tool Specialty Company | 2144A15 | 000000 | ||
Built-in-Pilot Counterbore Sets
 |
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 | Mfr. | Each | |||
|---|---|---|---|---|---|---|---|---|
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 | Alvord-Polk Tool | 2919A12 | 0000000 | ||
Counterbore Insert Holders
 |
Shown with Inserts (Sold Separately) |
Designed to reduce waste and costs during high-volume jobs, these counterbores consist of both an insert and a holder. When the cutting edges dull, you can replace the insert rather than the entire tool. The inserts are locked in place with a screw for a hold that’s strong enough to handle the high speeds of a CNC machine. These counterbores create flat-bottomed holes that allow socket head screws to sit flush with the surface of your material.
Counterbore Insert Holders | Replacement Insert Screws | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dia. | |||||||||||||
For Screw Size | Body | Shank | Overall Lg. | Max. Hole Drilling Dp. | No. of Inserts Req. | Mfr. | Each | Pkg. Qty. | Pkg. | ||||
Steel | |||||||||||||
| 1/4" | 0.422" | 3/4" | 2 7/8" | 0.54" | 1 | Kyocera | 8129N122 | 0000000 | 10 | 8129N133 | 000000 | ||
| 5/16" | 0.515" | 3/4" | 2 7/8" | 0.54" | 1 | Kyocera | 8129N125 | 000000 | 10 | 8129N133 | 00000 | ||
| 3/8" | 0.515" | 3/4" | 2 7/8" | 0.54" | 1 | Kyocera | 8129N124 | 000000 | 10 | 8129N133 | 00000 | ||
| 7/16" | 0.703" | 3/4" | 2 7/8" | 0.54" | 1 | Kyocera | 8129N127 | 000000 | 10 | 8129N133 | 00000 | ||
| 1/2" | 0.797" | 3/4" | 3 1/4" | 0.79" | 2 | Kyocera | 8129N121 | 000000 | 10 | 8129N133 | 00000 | ||
| 5/8" | 1" | 3/4" | 3 1/4" | 0.79" | 2 | Kyocera | 8129N126 | 000000 | 10 | 8129N133 | 00000 | ||
| 3/4" | 1.187" | 3/4" | 3 1/4" | 0.79" | 2 | Kyocera | 8129N123 | 000000 | 10 | 8129N133 | 00000 | ||
| M6 | 0.440" | 3/4" | 2 7/8" | 0.54" | 1 | Kyocera | 8129N131 | 000000 | 10 | 8129N133 | 00000 | ||
| M8 | 0.558" | 3/4" | 2 7/8" | 0.54" | 1 | Kyocera | 8129N132 | 000000 | 10 | 8129N133 | 00000 | ||
| M10 | 0.676" | 3/4" | 2 7/8" | 0.54" | 1 | Kyocera | 8129N128 | 000000 | 10 | 8129N133 | 00000 | ||
| M12 | 0.755" | 3/4" | 3 1/4" | 0.79" | 2 | Kyocera | 8129N129 | 000000 | 10 | 8129N133 | 00000 | ||
 |  |
Individual Carbide Insert Case |
Inserts have a positive rake, which means the cutting edge is angled to reduce vibration and prevent thin workpieces from bending. For longer life, each insert has three cutting edges—when one edge dulls, rotate to the next one. They have chip breakers to stop long chips from forming, so they won’t block the flow of coolant or damage your tool. Inserts sold individually come packed in a clear plastic case to protect cutting edges during shipment. Inserts sold in packs come factory sealed from the manufacturer for maximum traceability.
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.
For Screw Size | No. of Pieces | Oversize Amount | Shank Type | No. of Flutes | Mfr. | Each | |||
|---|---|---|---|---|---|---|---|---|---|
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 | 1/64" | Round | 4 | Alvord-Polk Tool | 2919A14 | 0000000 | ||
| No. 4, No. 5, No. 6, No. 8, No. 10, 1/4", 5/16", 3/8", 7/16", 1/2" | 10 | 1/32" | Round | 4 | Alvord-Polk Tool | 2919A16 | 000000 | ||
| M3, M4, M5, M6, M8, M10, M12, M14 | 8 | 0.5 mm | Round | 4 | Alvord-Polk Tool | 2740A19 | 000000 | ||
