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    10 Products
    About Counterbores
    industrial info icon

    Create flat-bottomed holes, so your screw heads sit flush, recessed, or slightly raised.

    For Cutting

    Size Designation

    Sold As

    Built-in-Pilot Counterbore Sets

    Image of Product. Front orientation. Counterbores. 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"
    		10Round4Alvord-Polk Tool2919A120000000
     

    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 SteelAbout High-Speed Steel
    Image of Product. Front orientation. ZoomedIn view. Counterbores. Built-in-Pilot Counterbores.
    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"Round4Alvord-Polk Tool2919A3100000028225A31000000
     

    Counterbores for High-Profile Rounded-Head Screws

    Cut flat, close-fitting recesses for fillister-head screws. These counterbores cut deeply enough for screws with tall head profiles to sit flush with the surface.
    High-Speed SteelAbout High-Speed Steel
    Image of Product. Front orientation. Counterbores. Counterbores for High-Profile Rounded-Head Screws.
    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. 4
    		0.198"2 5/8"Round20.170"Republic Drill2909A15000000
     

    Oversized Counterbore Sets

    Image of Product. Front orientation. Counterbores. 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"
    		101/64"Round4Alvord-Polk Tool2919A140000000
    No. 4, No. 5, No. 6, No. 8, No. 10, 1/4", 5/16", 3/8", 7/16", 1/2"
    		101/32"Round4Alvord-Polk Tool2919A16000000
     

    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 SteelAbout High-Speed Steel
    Image of Product. Front orientation. ZoomedIn view. Counterbores. Oversized Counterbores.
    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"Round4Alvord-Polk Tool2919A5100000028225A51000000
     
    1/32" Oversize
    No. 4
    		0.221"0.143"0.156"3 7/8"5/32"Round4Alvord-Polk Tool2919A710000028225A7100000
     
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