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    170 Products
    About Counterbores
    industrial info icon

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

    Changeable-Pilot Counterbores

    A popular choice when counterboring for nonstandard screw sizes, this tool creates counterbored holes for screws of various thread diameters. Attach a pilot (sold separately) that matches the diameter of your pilot hole. The pilot centers the counterbore and prevents wobbling to create an accurate recess for the screw head on the first try.
    High-Speed Steel
    Image of Product. Shown with Pilot (Sold Separately). Front orientation. Counterbores. Changeable-Pilot Counterbores.

    Shown with Pilot (Sold Separately)

    Durable and wear resistant, these counterbores make accurate cuts in most materials without chipping or cracking.
    Shank
    Uncoated
    Body
    Dia.
    Overall
    Lg.
    For Pilot
    Shank Dia.
    Dia.
    Type
    No. of
    Flutes
    Each
    3/16"3"3/32"15/64"Round33015A110000000
    7/32"3"3/32"15/64"Round33015A12000000
    1/4"2 3/8"3/32"1/4"Round43102A1100000
    1/4"3 13/16"3/32"15/64"Round33015A1300000
    9/32"2 3/8"3/32"1/4"Round43102A1200000
    9/32"3 13/16"3/32"17/64"Round33015A1400000
    5/16"2 3/8"3/32"1/4"Round43102A1300000
    5/16"3 13/16"3/32"17/64"Round33015A1500000
    11/32"2 3/8"3/32"1/4"Round43102A1400000
    11/32"3 13/16"3/32"5/16"Round33015A1600000
    3/8"2 3/8"3/32"1/4"Round43102A1500000
    3/8"4 1/16"5/32"5/16"Round33015A1700000
    13/32"2 13/16"1/8"1/4"Round43102A1600000
    13/32"4 1/16"5/32"3/8"Round33015A1800000
    7/16"2 13/16"1/8"1/4"Round43102A1700000
    7/16"4 1/16"5/32"3/8"Round33015A1900000
    15/32"2 13/16"1/8"1/4"Round43102A1800000
    15/32"4 5/16"3/16"7/16"Round33015A2100000
    1/2"2 13/16"1/8"1/4"Round43102A1900000
    1/2"4 5/16"3/16"7/16"Round33015A2200000
    17/32"2 13/16"1/8"1/4"Round43102A2100000
    17/32"4 5/16"3/16"1/2"Round33015A2300000
    9/16"2 13/16"1/8"1/4"Round43102A2200000
    9/16"4 5/16"3/16"1/2"Round33015A2400000
    19/32"2 13/16"1/8"1/4"Round43102A2300000
    19/32"5 1/8"3/16"1/2"Round33015A2500000
    5/8"2 13/16"1/8"1/4"Round43102A2400000
    5/8"5 1/8"3/16"1/2"Round33015A2600000
    21/32"3 1/8"3/16"1/4"Round43102A2500000
    21/32"5 1/8"3/16"1/2"Round33015A2700000
    11/16"3 1/8"3/16"1/4"Round43102A2600000
    11/16"5 1/8"3/16"1/2"Round33015A2800000
    23/32"3 1/8"3/16"1/4"Round43102A2700000
    23/32"5 3/8"1/4"1/2"Round33015A2900000
    3/4"3 1/8"3/16"1/4"Round43102A2800000
    3/4"5 3/8"1/4"1/2"Round33015A3100000
    25/32"3 1/8"3/16"1/4"Round43102A2900000
    25/32"5 1/8"1/4"5/8"Round33015A3200000
    13/16"3 1/8"3/16"1/4"Round43102A3100000
    13/16"5 1/8"1/4"5/8"Round33015A33000000
    7/8"3 1/8"3/16"1/4"Round43102A3300000
    7/8"5 3/8"1/4"3/4"Round33015A34000000
    15/16"3 1/8"3/16"1/4"Round43102A35000000
    15/16"6 1/8"1/4"3/4"Round33015A4300000
    1"3 1/8"3/16"1/4"Round43102A37000000
    1"6 3/8"5/16"3/4"Round33015A36000000
    1 1/8"6 3/8"5/16"1"Round33015A38000000
     
    Counterbore Pilots
    Image of Product. Front orientation. Counterbore Pilots.
    Pilot Head
    Dia.
    Pilot
    Lg.
    Each
    Uncoated Carbon Steel
     
    3/32" Diameter Pilot Shank
    3/32"3/32"3103A100000
    1/8"1/8"3103A110000
    5/32"5/32"3103A120000
    3/16"3/16"3103A130000
    7/32"7/32"3103A140000
    1/4"1/4"3103A150000
     
    1/8" Diameter Pilot Shank
    1/8"1/8"3103A160000
    5/32"5/32"3103A170000
    3/16"3/16"3103A180000
    7/32"7/32"3103A190000
    1/4"1/4"3103A20000
    5/16"5/16"3103A2100000
    3/8"3/8"3103A2200000
     
    5/32" Diameter Pilot Shank
    3/16"3/16"3103A230000
    7/32"7/32"3103A2400000
    1/4"1/4"3103A250000
    9/32"9/32"3103A6100000
    5/16"5/16"3103A2600000
    3/8"3/8"3103A2700000
     
    3/16" Diameter Pilot Shank
    3/16"3/16"3103A640000
    1/4"1/4"3103A280000
    9/32"9/32"3103A6200000
    5/16"5/16"3103A2900000
    11/32"11/32"3103A6300000
    3/8"3/8"3103A300000
    13/32"13/32"3103A6500000
    7/16"7/16"3103A3100000
    15/32"15/32"3103A6600000
    1/2"1/2"3103A3200000
    17/32"17/32"3103A4800000
    9/16"9/16"3103A3300000
    5/8"5/8"3103A3400000
     
    1/4" Diameter Pilot Shank
    5/16"5/16"3103A350000
    3/8"3/8"3103A3600000
    7/16"7/16"3103A3700000
    1/2"1/2"3103A3800000
    9/16"9/16"3103A3900000
    5/8"5/8"3103A400000
    11/16"11/16"3103A4100000
    3/4"3/4"3103A4200000
    13/16"13/16"3103A4300000
     
    5/16" Diameter Pilot Shank
    3/8"3/8"3103A4500000
    7/16"7/16"3103A4600000
    1/2"1/2"3103A4700000
    5/8"5/8"3103A4900000
    11/16"11/16"3103A500000
    3/4"3/4"3103A5100000
    1"1"3103A5500000
     
    Carbide-Tipped Steel
    Image of Product. Shown with Pilot (Sold Separately). Front orientation. Counterbores. Changeable-Pilot Counterbores.

    Shown with Pilot (Sold Separately)

    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.
    Shank
    Uncoated
    Body
    Dia.
    Overall
    Lg.
    For Pilot
    Shank Dia.
    Dia.
    Type
    No. of
    Flutes
    Each
    C2 Carbide
    1/4"2 3/8"3/32"1/4"Round331125A21000000
    1/4"3 13/16"3/32"15/64"Round32814A81000000
    9/32"2 3/8"3/32"1/4"Round331125A2200000
    9/32"3 13/16"3/32"17/64"Round32814A421000000
    5/16"2 3/8"3/32"1/4"Round331125A2300000
    5/16"3 13/16"3/32"19/64"Round32814A591000000
    11/32"2 3/8"3/32"1/4"Round331125A2400000
    11/32"3 13/16"3/32"5/16"Round32814A311000000
    3/8"2 3/8"3/32"1/4"Round331125A2500000
    3/8"4 1/16"5/32"5/16"Round32814A83000000
    13/32"2 3/4"1/8"1/4"Round331125A2600000
    13/32"4 1/16"5/32"3/8"Round32814A321000000
    7/16"2 3/4"1/8"1/4"Round331125A2700000
    7/16"4 1/16"5/32"3/8"Round32814A84000000
    15/32"2 3/4"1/8"1/4"Round331125A2800000
    15/32"4 5/16"3/16"7/16"Round32814A331000000
    1/2"2 3/4"1/8"1/4"Round331125A2900000
    1/2"4 5/16"3/16"7/16"Round32814A85000000
    17/32"2 3/4"1/8"1/4"Round331125A3100000
    17/32"4 5/16"3/16"1/2"Round32814A341000000
    9/16"2 3/4"1/8"1/4"Round331125A3200000
    9/16"4 5/16"3/16"1/2"Round32814A86000000
    19/32"2 3/4"1/8"1/4"Round331125A3300000
    19/32"5 1/8"3/16"1/2"Round32814A351000000
    5/8"2 3/4"1/8"1/4"Round331125A3400000
    5/8"5 1/8"3/16"1/2"Round32814A87000000
    21/32"2 3/4"3/16"1/4"Round331125A35000000
    21/32"5 1/8"3/16"1/2"Round32814A361000000
    11/16"2 3/4"3/16"1/4"Round331125A36000000
    11/16"5 1/8"3/16"1/2"Round32814A371000000
    23/32"2 3/4"3/16"1/4"Round331125A37000000
    23/32"5 3/8"1/4"1/2"Round32814A381000000
    3/4"2 3/4"3/16"1/4"Round331125A38000000
    3/4"5 3/8"1/4"1/2"Round32814A89000000
    25/32"2 3/4"3/16"1/4"Round331125A39000000
    25/32"5 3/8"1/4"5/8"Round32814A391000000
    13/16"2 3/4"3/16"1/4"Round331125A41000000
    13/16"5 3/8"1/4"5/8"Round32814A91000000
    7/8"2 3/4"3/16"1/4"Round331125A43000000
    7/8"5 3/8"1/4"3/4"Round32814A531000000
    15/16"2 3/4"3/16"1/4"Round331125A45000000
    15/16"6 1/8"1/4"3/4"Round32814A561000000
    1"2 3/4"3/16"1/4"Round331125A47000000
    1"6 3/8"5/16"3/4"Round32814A94000000
    1 1/8"6 3/8"5/16"1"Round32814A581000000
     
    C5 Carbide
    1/4"3 13/16"3/32"15/64"Round32814A61000000
    9/32"3 13/16"3/32"17/64"Round32814A422000000
    5/16"3 13/16"3/32"19/64"Round32814A592000000
    11/32"3 13/16"3/32"5/16"Round32814A312000000
    3/8"4 1/16"5/32"5/16"Round32814A63000000
    13/32"4 1/16"5/32"3/8"Round32814A322000000
    7/16"4 1/16"5/32"3/8"Round32814A64000000
    15/32"4 5/16"3/16"7/16"Round32814A332000000
    1/2"4 5/16"3/16"7/16"Round32814A65000000
    17/32"4 5/16"3/16"1/2"Round32814A342000000
    9/16"4 5/16"3/16"1/2"Round32814A66000000
    19/32"5 1/8"3/16"1/2"Round32814A352000000
    5/8"5 1/8"3/16"1/2"Round32814A67000000
    21/32"5 1/8"3/16"1/2"Round32814A362000000
    11/16"5 1/8"3/16"1/2"Round32814A372000000
    23/32"5 3/8"1/4"1/2"Round32814A382000000
    3/4"5 3/8"1/4"1/2"Round32814A69000000
    25/32"5 3/8"1/4"5/8"Round32814A392000000
    13/16"5 3/8"1/4"5/8"Round32814A71000000
    7/8"5 3/8"1/4"3/4"Round32814A532000000
    15/16"6 1/8"1/4"3/4"Round32814A562000000
    1"6 3/8"5/16"3/4"Round32814A74000000
    1 1/8"6 3/8"5/16"1"Round32814A582000000
     
    Counterbore Pilots
    Image of Product. Front orientation. Counterbore Pilots.
    Pilot Head
    Dia.
    Pilot
    Lg.
    Each
    Uncoated Carbon Steel
     
    3/32" Diameter Pilot Shank
    3/32"3/32"3103A100000
    1/8"1/8"3103A110000
    5/32"5/32"3103A120000
    3/16"3/16"3103A130000
    7/32"7/32"3103A140000
    1/4"1/4"3103A150000
     
    1/8" Diameter Pilot Shank
    1/8"1/8"3103A160000
    5/32"5/32"3103A170000
    3/16"3/16"3103A180000
    7/32"7/32"3103A190000
    1/4"1/4"3103A20000
    5/16"5/16"3103A2100000
    3/8"3/8"3103A2200000
     
    5/32" Diameter Pilot Shank
    3/16"3/16"3103A230000
    7/32"7/32"3103A2400000
    1/4"1/4"3103A250000
    9/32"9/32"3103A6100000
    5/16"5/16"3103A2600000
    3/8"3/8"3103A2700000
     
    3/16" Diameter Pilot Shank
    3/16"3/16"3103A640000
    1/4"1/4"3103A280000
    9/32"9/32"3103A6200000
    5/16"5/16"3103A2900000
    11/32"11/32"3103A6300000
    3/8"3/8"3103A300000
    13/32"13/32"3103A6500000
    7/16"7/16"3103A3100000
    15/32"15/32"3103A6600000
    1/2"1/2"3103A3200000
    17/32"17/32"3103A4800000
    9/16"9/16"3103A3300000
    5/8"5/8"3103A3400000
     
    1/4" Diameter Pilot Shank
    5/16"5/16"3103A350000
    3/8"3/8"3103A3600000
    7/16"7/16"3103A3700000
    1/2"1/2"3103A3800000
    9/16"9/16"3103A3900000
    5/8"5/8"3103A400000
    11/16"11/16"3103A4100000
    3/4"3/4"3103A4200000
    13/16"13/16"3103A4300000
     
    5/16" Diameter Pilot Shank
    3/8"3/8"3103A4500000
    7/16"7/16"3103A4600000
    1/2"1/2"3103A4700000
    5/8"5/8"3103A4900000
    11/16"11/16"3103A500000
    3/4"3/4"3103A5100000
    1"1"3103A5500000
     

    Changeable-Pilot Counterbores Sets

    Image of Product. Front orientation. Counterbores. Changeable-Pilot Counterbores Sets.
    A handful of counterbores and changeable pilots give you the versatility of dozens of normal counterbores. For each hole, mix and match counterbores and pilots to correspond with your screw-head and screw-shank diameter.
    High-Speed Steel—Durable and wear resistant, these counterbores make accurate cuts in most materials without chipping or cracking.
    Body Dia.
    No. of
    Pieces
    Shank
    Type
    Includes
    Container
    Type
    Each
    Uncoated High-Speed Steel
    1/4", 5/16", 3/8", 7/16", 1/2"5Round10 PilotsWood Case2817A710000000
     

    Adjustable-Diameter Counterbores

    Skip buying different tools to counterbore multiple diameters. Use the set screw on these counterbores to adjust the blades to the diameter you need.
    The included replaceable pilot has the minimum pilot head diameter recommended for use with these counterbores. If your application requires a larger pilot head diameter, choose a Steel Pilot for Changeable-Pilot Counterbores with the same shank diameter as the included pilot. These counterbores require rigid tool holding to prevent breakage and are not for use with hand-held tools.
    High-Speed Steel Blade
    Image of Product. Front orientation. Counterbores. Adjustable-Diameter Counterbores, Round Shank.
    Image of Product. Front orientation. Counterbores. Adjustable-Diameter Counterbores, Morse Taper Shank.

    Round Shank

    Morse Taper Shank

    Durable and wear resistant, these blades make accurate cuts in most materials without chipping or cracking.
    Counterbores
    Replacement
    Counterbore Blades
    Shank
    Body Dia.
    Overall
    Lg.
    Dia.
    Type
    Machine
    Taper No.
    Pilot
    Lg.
    No. of
    Flutes
    Pilot Head
    Dia.
    Pilot Shank
    Dia.
    Each
    Pkg.
    Qty.
    Pkg.
    1" to 1 1/4"4"1/2"Round0.438"27/16"3/16"3104A11000000023104A310000000
    1 1/4" to 1 5/8"4 3/8"1/2"Round0.563"29/16"1/4"3104A1400000023104A32000000
    2 1/8" to 2 7/8"6"Morse TaperMorse 30.750"23/4"3/8"3104A2200000023104A34000000
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