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)
    26 Products

    Fluteless Smooth-Finish Countersinks 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
    Image of Product. Front orientation. Countersinks. Fluteless Smooth-Finish Countersinks with Pilot for Screws, 0 Flutes.

    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
    7/16" to 53/64"53/64"1/2"7/16"7/32"7/16"
    		2 11/16"RoundRepublic Drill2739A71000000
     

    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
    Mfr.
    Each
    Uncoated High-Speed Steel
    No. 5, No. 6, No. 8, No. 10, 1/4", 5/16", 3/8", 7/16", 1/2"
    		9Round2Plastic CaseLink Industries9940N1110000000
    No. 5, No. 6, No. 8, No. 10, 1/4", 5/16", 3/8", 7/16", 1/2"
    		9Round2Plastic CaseLink Industries9940N112000000
     

    Countersink Drill Bits for Screws

    Image of Product. Front orientation. Contains Annotated. Countersink Drill Bits. Countersink Drill Bits for Screws.
    Also known as step drill bits, these bits countersink as they drill. The 82° countersink angle is compatible with the profile of flat- and oval-head inch screws. After multiple sharpenings, the drill bit diameter may become smaller.
    Dia.
    Lg.
    82°
    Countersink Angle
    For Screw
    Size
    Body
    Step
    Step
    Overall
    Shank
    Dia.
    Point
    Angle
    For Use On
    Mfr.
    Each
    Uncoated High-Speed Steel
     
    2 Flutes
    7/16"
    		0.813"0.446"1"5 1/4"0.8125"118°Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, SteelRepublic Drill8914A580000000
     

    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 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
    7/16"
    		0.663"7/16"0.500"7"1/2"Round4Alvord-Polk Tool2919A3900000028225A390000000
     
    Carbide-Tipped Steel
    Image of Product. Front orientation. ZoomedIn view. Counterbores. Built-In-Pilot Counterbores.
    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
    7/16"
    		0.663"7/16"0.500"7"1/2"Round3Rock River Tool3218A1410000000
     
    C5 Carbide
    7/16"
    		0.663"7/16"0.500"7"1/2"Round3Rock River Tool3218A241000000
     

    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.
    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
    7/16"
    		0.679"0.453"0.500"7"1/2"Round4Alvord-Polk Tool2919A5900000028225A590000000
     
    1/32" Oversize
    7/16"
    		0.694"0.469"0.500"7"1/2"Round4Alvord-Polk Tool2919A790000028225A79000000
     
    Carbide-Tipped Steel
    Image of Product. Front orientation. ZoomedIn view. Counterbores. Oversized Counterbores.
    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
    7/16"
    		0.679"29/64"0.500"7"1/2"Round3Rock River Tool3218A1430000000
     
    1/32" Oversize
    7/16"
    		0.694"15/32"0.500"7"1/2"Round3Rock River Tool3218A142000000
     
    C5 Carbide
     
    1/64" Oversize
    7/16"
    		0.679"29/64"0.500"7"1/2"Round3Rock River Tool3218A243000000
     
    1/32" Oversize
    7/16"
    		0.694"15/32"0.500"7"1/2"Round3Rock River Tool3218A242000000
     

    Counterbore Drill Bits

    Image of Product. Front orientation. Contains Annotated. Counterbore Drill Bits. Counterbore Drill Bits.
    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.
    For Screw
    Size
    Body
    Step
    Step
    Overall
    Point
    Angle
    For Use On
    Mfr.
    Each
    Uncoated High-Speed Steel
    7/16"
    		0.688"0.469"1"7 5/8"118°Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, SteelRepublic Drill8914A38000000
     

    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
     

    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.
    Overall
    Lg.
    Dia.
    Type
    No. of
    Flutes
    Max. Hole
    Drilling Dp.
    Mfr.
    Each
    7/16"
    		0.687"2 1/2"5/8"Round20.5"Link Industries29445A18000000
    7/16"
    		0.687"4"1/2"Round21.404"Link Industries29445A31800000
     

    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.
    Mfr.
    Each
    Pkg.
    Qty.
    Pkg.
    Steel
    7/16"
    		0.703"3/4"2 7/8"0.54"1Kyocera8129N1270000000108129N133000000
     
    Carbide Inserts
    Image of Product. 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, Steel8909N122000000108909N121000000
     
    back to top