McMaster-Carr logo
    Forward
    Enter e-mail addresses in the fields below
    Message
    Cancel
    Print
    How can we improve?
    Comments
    E-mail address (if you would like a response)
    8 Products
    About Counterbores
    industrial info icon

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

    Drill-Point Counterbore Sets

    Image of Product. Front orientation. Counterbores. Drill-Point Counterbore Sets.
    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.
    For Screw Size
    No. of
    Pieces
    Shank
    Type
    No. of
    Flutes
    Container
    Type
    Each
    Uncoated High-Speed Steel
    M3, M4, M5, M6, M8, M10, M12, M14, M16
    		9Round2Plastic Case000000000000000
     

    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, mm
    Shank
    Type
    No. of
    Flutes
    Each
    Uncoated High-Speed Steel
    M3, M4, M5, M6, M8, M10, M12, M14
    		80.5Round400000000000000
     

    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
    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.
    Pilot
    Shank
    Uncoated
    For Screw
    Size
    Body Dia.,
    mm
    Dia.,
    mm
    Lg.
    Overall
    Lg.
    Dia.
    Type
    No. of
    Flutes
    Each
     
    0.5 mm Oversize
    M12
    		18.512.50.500"7 1/8"1/2"Round40000000000000
     

    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
    Image of Product. Front orientation. Counterbores. Drill-Point Counterbores.
    Durable and wear resistant, these counterbores make accurate cuts in most materials without chipping or cracking.
    Shank
    Uncoated
    For Screw
    Size
    Body Dia.,
    mm
    Overall
    Lg.
    Dia.
    Type
    No. of
    Flutes
    Max. Hole Drilling
    Dp., mm
    Each
    M12
    		18.72 7/16"5/8"Round215.8700000000000000
     

    Counterbore Insert Holders

    Image of ProductInUse. Shown with Inserts (Sold Separately). Front orientation. 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.
    Each
    Pkg.
    Qty.
    Pkg.
    Steel
    M12
    		0.755"3/4"3 1/4"0.79"20000000000000001000000000000000
     
    Carbide Inserts
    Image of ProductInUse. Individual Carbide Insert Case. Front orientation. Counterbore Inserts.
    Image of Product. Front orientation. Counterbore Inserts.

    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.
    Each
    Package
    IC
    Dia.
    Thk.
    Cutting
    Edge Lg.
    Tip
    Radius
    For Use On
    Each
    Pkg.
    Qty.
    Pkg.
    Titanium Nitride (TiN) Coated
    7/32"3/32"0.35"1/64"Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel00000000000001000000000000000
     
    back to top