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)
    72 Products

    Rounded Machine Keys

    Image of Product. Front orientation. Machine Keys. Rounded Machine Keys.
    When installed, these keys fill oval keyways completely, reducing stress on the key and shaft. Using them in a closed keyway keeps them from sliding along the shaft axis. The rounded ends make it easy to slide gears, hubs, and other components into place. These are also known as feather keys. Machine keys are often the same material as the shaft and other components with which they are used. To use a key as a sacrificial part, choose a softer key that will shear off when parts are exposed to excessive force, preventing damage to expensive equipment.
    1008-1045 Carbon Steel and 1045 Carbon Steel—Steel keys are strong and easy to machine. Since steel is the most common material, these keys work in many applications. Steel keys rust when exposed to moisture, so they should only be used in dry environments.
    316 Stainless Steel—316 stainless steel keys have excellent corrosion resistance, but aren't as strong as steel keys. They may be mildly magnetic.
    Oversized Tolerance—Slightly larger than the size listed in the table, oversized keys fit tightly in a keyway. Press them into place for use in high-torque applications or to replace a key in a worn keyway.
    Undersized Tolerance—Slightly smaller than the size listed in the table, undersized keys are the choice when you need a slightly looser fit or when you have an inconsistent keyway. Use them when parts need to be taken apart frequently, such as for maintenance or prototyping. Undersized metric keys meet DIN 6885 dimensional standards.
    Tolerance,
    mm
    Lg.,
    mm
    Tolerance
    Rating
    Ht.
    Wd.
    Min.
    Hardness
    Specs.
    Met
    Pkg.
    Qty.
    Pkg.
    1008-1045 Carbon Steel
     
    4 mm × 4 mm
    18Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 6885596717A14100000
    22Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 6885596717A1520000
    40Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 6885596717A1560000
    56Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 6885596717A1650000
     
    1045 Carbon Steel
     
    4 mm × 4 mm
    8Undersized-0.030 to 0.000-0.030 to 0.000Rockwell B87DIN 68851096717A1000000
    10Undersized-0.030 to 0.000-0.030 to 0.000Rockwell B87DIN 68851096717A11000000
    12Undersized-0.030 to 0.000-0.030 to 0.000Rockwell B87DIN 68851096717A12000000
    14Undersized-0.030 to 0.000-0.030 to 0.000Rockwell B87DIN 68851096717A13000000
    16Oversized0.000 to 0.0760.000 to 0.076Rockwell B87—596717A1080000
    16Undersized-0.030 to 0.000-0.030 to 0.000Rockwell B87DIN 68851096717A1400000
    20Oversized0.000 to 0.0760.000 to 0.076Rockwell B87—596717A1310000
    20Undersized-0.030 to 0.000-0.030 to 0.000Rockwell B87DIN 68851096717A1450000
    25Undersized-0.030 to 0.000-0.030 to 0.000Rockwell B87DIN 68851096717A14700000
     
    316 Stainless Steel
     
    4 mm × 4 mm
    8Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 688552977N140000
    10Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 688552977N150000
    12Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 688552977N1600000
    14Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 688552977N1700000
    15Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 688552977N5700000
    16Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 688552977N1800000
    18Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 688552977N5800000
    20Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 688552977N1900000
    22Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 688552977N5900000
    25Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 688552977N2100000
    28Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 688552977N6100000
    32Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 688552977N6300000
    35Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 688552977N6400000
    36Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 688552977N6500000
    40Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 688552977N6600000
    45Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 688552977N6700000
    50Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 688552977N6800000
     

    Machine Keys

    Image of Product. Front orientation. Machine Keys. Machine Keys.
    Straight keys, with a square or rectangular cross section, are the most common type of key. Install them in keyways to transmit torque from shafts to gears and other components. Machine keys are often the same material as the shaft and other components with which they are used. To use a key as a sacrificial part, choose a softer key that will shear off when parts are exposed to excessive force, preventing damage to expensive equipment.
    1008-1045 Carbon Steel and 1045 Carbon Steel—Steel keys are strong and easy to machine. Since steel is the most common material, these keys work in many applications. Steel keys rust when exposed to moisture, so they should only be used in dry environments.
    Oversized Tolerance—Slightly larger than the size listed in the table, oversized keys fit tightly in a keyway. Press them into place for use in high-torque applications or to replace a key in a worn keyway.
    Undersized Tolerance—Slightly smaller than the size listed in the table, undersized keys are the choice when you need a slightly looser fit or when you have an inconsistent keyway. Use them when parts need to be taken apart frequently, such as for maintenance or prototyping.
    Tolerance,
    mm
    Lg.,
    mm
    Tolerance
    Rating
    Ht.
    Wd.
    Min.
    Hardness
    Specs.
    Met
    Pkg.
    Qty.
    Pkg.
    1008-1045 Carbon Steel
     
    4 mm × 4 mm
    8Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 6885598870A71200000
    10Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 6885598870A7130000
    12Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 6885598870A7140000
    14Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 6885598870A7150000
    16Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 6885598870A7160000
    18Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 6885598870A7170000
    20Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 6885598870A7180000
    22Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 6885598870A7190000
    25Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 6885598870A7210000
    40Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 6885598870A7220000
    56Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 6885598870A7230000
     
    1045 Carbon Steel
     
    4 mm × 4 mm
    16Oversized0.000 to 0.0760.000 to 0.076Rockwell B87—598870A3430000
    20Oversized0.000 to 0.0760.000 to 0.076Rockwell B87—598870A3440000
     
    316 Stainless Steel
     
    4 mm × 4 mm
    12Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 6885598870A1590000
    14Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 6885598870A1630000
    15Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 6885598870A1640000
    20Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 6885598870A1720000
    25Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 6885598870A1750000
    28Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 6885598870A1770000
    30Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 6885598870A1810000
    32Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 6885598870A1850000
    35Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 6885598870A2020000
    40Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 6885598870A20700000
    50Undersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 6885598870A21000000
     

    Woodruff Keys

    Image of Product. Front orientation. Contains Annotated. Machine Keys. Woodruff Keys.
    Image of Attribute. Side View. Front orientation. Contains Annotated. Woodruff Keys.

    Side View

    Woodruff keys work well near shaft shoulders, where a standard open keyway would create too much stress. They are also often used on tapered shafts. These keys have a rounded shape that makes them easy to remove when parts need to be taken apart frequently, such as for maintenance or prototyping. Because they're usually shorter than standard machine keys, they work best in light duty applications. Use them to connect gears and other components to shafts. Also known as half moon keys.
    1018-1045 Carbon Steel—Steel keys offer good strength.
    316 Stainless Steel—316 stainless steel keys have excellent corrosion resistance, but aren't as strong as steel keys. They may be mildly magnetic.
    Metric—Metric keys conform to DIN 6888 standards.
    Tolerance,
    mm
    Wd.,
    mm
    For Keyway
    Dia., mm
    Ht.,
    mm
    Lg.,
    mm
    Wd.
    Ht.
    Specs.
    Met
    System of
    Measurement
    Pkg.
    Qty.
    Pkg.
    1018-1045 Carbon Steel
    413512.7-0.030 to 0.000—DIN 6888Metric2598490A190000000
    4166.515.7-0.030 to 0.000—DIN 6888Metric2598490A20000000
    4197.518.6-0.030 to 0.000—DIN 6888Metric2598490A21000000
     
    316 Stainless Steel
    4166.515.7-0.030 to 0.000-0.150 to 0.000DIN 6888Metric197940A13500000
     

    Machine Key Stock

    Cut this square or rectangular key stock to length to create a straight machine key. Straight keys are the most common type of key. Machine keys are often the same material as the shaft and other components with which they are used. To use a key as a sacrificial part, choose a softer key that will shear off when parts are exposed to excessive force, preventing damage to expensive equipment.
    1008-1045 Carbon Steel
    Image of Product. Front orientation. Machine Key Stock. Machine Key Stock.
    1008-1045 carbon steel key stock is an economical choice with good strength.
    Oversized Tolerance—Slightly larger than the size listed in the table, oversized stock fits tightly in a keyway. Press it into place for use in high-torque applications or to replace a key in a worn keyway.
    Undersized Tolerance—Slightly smaller than the size listed in the table, undersized stock is the choice when you need a slightly looser fit or when you have an inconsistent keyway. Use it when parts need to be taken apart frequently, such as for maintenance or prototyping.
    DIN 6880—Key stock that meets DIN 6880 conforms to DIN standards for undersized keys.
    Tolerance,
    mm
    Ht. × Wd.
    Tolerance
    Rating
    Ht.
    Wd.
    Min.
    Hardness
    Specs.
    Met
    Each
    305 mm Long
    4 mm × 4 mmOversized0.000 to 0.0760.000 to 0.076Rockwell B87—92288A49000000
    4 mm × 4 mmUndersized-0.030 to 0.000-0.030 to 0.000Rockwell B87DIN 688092288A7200000
     
    1,000 mm Long
    4 mm × 4 mmUndersized-0.030 to 0.000-0.030 to 0.000Rockwell B87DIN 688092288A5650000
     
    Zinc-Plated 1008-1045 Carbon Steel
    Image of Product. Front orientation. Machine Key Stock. Machine Key Stock.
    Zinc-plated 1008-1045 carbon steel key stock is an economical choice with good strength and resists corrosion in wet environments.
    Oversized Tolerance—Slightly larger than the size listed in the table, oversized stock fits tightly in a keyway. Press it into place for use in high-torque applications or to replace a key in a worn keyway.
    Tolerance,
    mm
    Ht. × Wd.
    Tolerance
    Rating
    Ht.
    Wd.
    Min.
    Hardness
    Each
    305 mm Long
    4 mm × 4 mmOversized0.000 to 0.0760.000 to 0.076Rockwell B8792288A11000000
     
    Zinc-Yellow-Chromate-Plated 1045 Carbon Steel
    Image of Product. Front orientation. Machine Key Stock. Machine Key Stock.
    Zinc-yellow-chromate-plated 1045 carbon steel key stock is an economical choice with good strength and resists corrosion in wet environments.
    Undersized Tolerance—Slightly smaller than the size listed in the table, undersized stock is the choice when you need a slightly looser fit or when you have an inconsistent keyway. Use it when parts need to be taken apart frequently, such as for maintenance or prototyping.
    DIN 6880—Key stock that meets DIN 6880 conforms to DIN standards for undersized keys.
    Tolerance,
    mm
    Ht. × Wd.
    Tolerance
    Rating
    Ht.
    Wd.
    Min.
    Hardness
    Specs.
    Met
    Each
    305 mm Long
    4 mm × 4 mmUndersized-0.030 to 0.000-0.030 to 0.000Rockwell B87DIN 688092288A76100000
     
    4140 Alloy Steel
    Image of Product. Front orientation. Machine Key Stock. Machine Key Stock.
    4140 alloy steel key stock is an economical choice with good strength. 4140 alloy steel key stock has greater strength and toughness after hardening than carbon steel, making it useful for high-stress applications.
    Undersized Tolerance—Slightly smaller than the size listed in the table, undersized stock is the choice when you need a slightly looser fit or when you have an inconsistent keyway. Use it when parts need to be taken apart frequently, such as for maintenance or prototyping.
    DIN 6880—Key stock that meets DIN 6880 conforms to DIN standards for undersized keys.
    Tolerance,
    mm
    Ht. × Wd.
    Tolerance
    Rating
    Ht.
    Wd.
    Min.
    Hardness
    Specs.
    Met
    Each
    305 mm Long
    4 mm × 4 mmUndersized-0.030 to 0.000-0.030 to 0.000Rockwell B90DIN 688092288A65700000
     
    1,000 mm Long
    4 mm × 4 mmUndersized-0.030 to 0.000-0.030 to 0.000Rockwell B90DIN 688092288A6680000
     
    18-8 Stainless Steel
    Image of Product. Front orientation. Machine Key Stock. Machine Key Stock.
    18-8 stainless steel key stock offers a balance of strength and corrosion resistance. It may be mildly magnetic. 18-8 stainless steel key stock is more corrosion resistant than steel key stock.
    Oversized Tolerance—Slightly larger than the size listed in the table, oversized stock fits tightly in a keyway. Press it into place for use in high-torque applications or to replace a key in a worn keyway.
    Undersized Tolerance—Slightly smaller than the size listed in the table, undersized stock is the choice when you need a slightly looser fit or when you have an inconsistent keyway. Use it when parts need to be taken apart frequently, such as for maintenance or prototyping.
    DIN 6880—Key stock that meets DIN 6880 conforms to DIN standards for undersized keys.
    Tolerance,
    mm
    Ht. × Wd.
    Tolerance
    Rating
    Ht.
    Wd.
    Min.
    Hardness
    Specs.
    Met
    Each
    305 mm Long
    4 mm × 4 mmOversized0.000 to 0.0760.000 to 0.076Rockwell B82DIN 17898810A10000000
    4 mm × 4 mmUndersized-0.030 to 0.000-0.030 to 0.000Not RatedDIN 688090457A4200000
     
    304 Stainless Steel
    Image of Product. Front orientation. Machine Key Stock. Machine Key Stock.
    304 stainless steel key stock offers a good balance of strength, corrosion resistance, and machinability. 304 stainless steel key stock is more corrosion resistant than steel key stock.
    Undersized Tolerance—Slightly smaller than the size listed in the table, undersized stock is the choice when you need a slightly looser fit or when you have an inconsistent keyway. Use it when parts need to be taken apart frequently, such as for maintenance or prototyping.
    DIN 6880—Key stock that meets DIN 6880 conforms to DIN standards for undersized keys.
    Tolerance,
    mm
    Ht. × Wd.
    Tolerance
    Rating
    Ht.
    Wd.
    Min.
    Hardness
    Specs.
    Met
    Each
    1,000 mm Long
    4 mm × 4 mmUndersized-0.030 to 0.000-0.030 to 0.000Rockwell B80DIN 688092288A615000000
     
    316 Stainless Steel
    Image of Product. Front orientation. Machine Key Stock. Machine Key Stock.
    316 stainless steel key stock has the best corrosion resistance of our stainless steel key stock and may be mildly magnetic. 316 stainless steel key stock is more corrosion resistant than steel key stock.
    Undersized Tolerance—Slightly smaller than the size listed in the table, undersized stock is the choice when you need a slightly looser fit or when you have an inconsistent keyway. Use it when parts need to be taken apart frequently, such as for maintenance or prototyping.
    DIN 6880—Key stock that meets DIN 6880 conforms to DIN standards for undersized keys.
    Tolerance,
    mm
    Ht. × Wd.
    Tolerance
    Rating
    Ht.
    Wd.
    Min.
    Hardness
    Specs.
    Met
    Each
    1,000 mm Long
    4 mm × 4 mmUndersized-0.030 to 0.000-0.030 to 0.000Rockwell B85DIN 688092288A638000000
     
    316/316L Stainless Steel
    Image of Product. Front orientation. Machine Key Stock. Machine Key Stock.
    316/316L stainless steel key stock has the best corrosion resistance of our stainless steel key stock and may be mildly magnetic. 316/316L stainless steel key stock is more corrosion resistant than steel key stock.
    Oversized Tolerance—Slightly larger than the size listed in the table, oversized stock fits tightly in a keyway. Press it into place for use in high-torque applications or to replace a key in a worn keyway.
    Undersized Tolerance—Slightly smaller than the size listed in the table, undersized stock is the choice when you need a slightly looser fit or when you have an inconsistent keyway. Use it when parts need to be taken apart frequently, such as for maintenance or prototyping.
    DIN 6880—Key stock that meets DIN 6880 conforms to DIN standards for undersized keys.
    Tolerance,
    mm
    Ht. × Wd.
    Tolerance
    Rating
    Ht.
    Wd.
    Min.
    Hardness
    Specs.
    Met
    Each
    305 mm Long
    4 mm × 4 mmOversized0.000 to 0.0760.000 to 0.076Not Rated—92288A159000000
    4 mm × 4 mmUndersized-0.030 to 0.000-0.030 to 0.000Rockwell B86DIN 688090457A1200000
     
    360 Brass
    Image of Product. Front orientation. Machine Key Stock. Machine Key Stock.
    360 brass key stock is corrosion resistant and nonmagnetic. 360 brass is softer than other metals, so it's often used for shear keys.
    Undersized Tolerance—Slightly smaller than the size listed in the table, undersized stock is the choice when you need a slightly looser fit or when you have an inconsistent keyway. Use it when parts need to be taken apart frequently, such as for maintenance or prototyping.
    DIN 6880—Key stock that meets DIN 6880 conforms to DIN standards for undersized keys.
    Tolerance,
    mm
    Ht. × Wd.
    Tolerance
    Rating
    Ht.
    Wd.
    Min.
    Hardness
    Specs.
    Met
    Each
    305 mm Long
    4 mm × 4 mmUndersized-0.030 to 0.000-0.030 to 0.000Rockwell B35DIN 688090457A720000000
     
    back to top