McMaster-Carr logo
    Filter by
    System of Measurement
    Washer Type
    Maximum Temperature
    Shape
    Minimum Temperature
    Specifications Met
    Finish
    Export Control Classification Number (ECCN)
    Industrial Info Snippet
    DFARS Specialty Metals
    Edge Type
    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

    Ultra-High-Temperature Ceramic Washers

    Image of Product. Front orientation. Washers. Ultra-High-Temperature Ceramic Washers.
    Our most heat-resistant washers, even at blistering temperatures up to 3000° F. They distribute pressure evenly under nuts and screws in industrial furnaces, kilns, and other extreme-temperature environments. Ceramic may crack or dent if subjected to hard bumps, however, so these washers are not recommended for high-vibration applications.
    Temp.
    Range
    For Screw
    Size
    ID
    OD
    Thk.
    Min.
    Max.,
    ° F
    Specs. Met
    Color
    Each
    No. 0
    		0.068"0.188"0.022" to 0.028"Not Rated3,000—Off-White00000000000000
    No. 2
    		0.094"0.250"0.028" to 0.036"Not Rated3,000—Off-White0000000000000
    No. 4
    		0.125"0.375"0.036" to 0.045"Not Rated3,000—Off-White0000000000000
    No. 5
    		0.141"0.406"0.036" to 0.045"Not Rated3,000—Off-White0000000000000
    No. 6
    		0.156"0.438"0.036" to 0.045"Not Rated3,000—Off-White0000000000000
    No. 8
    		0.188"0.500"0.036" to 0.045"Not Rated3,000—Off-White0000000000000
    No. 10
    		0.203"0.562"0.036" to 0.045"Not Rated3,000—Off-White0000000000000
    No. 12
    		0.234"0.625"0.056" to 0.071"Not Rated3,000—Off-White0000000000000
    1/4"
    		0.281"0.734"0.056" to 0.071"Not Rated3,000—Off-White0000000000000
    5/16"
    		0.344"0.875"0.056" to 0.071"Not Rated3,000—Off-White0000000000000
    3/8"
    		0.406"1.000"0.056" to 0.071"Not Rated3,000—Off-White0000000000000
    7/16"
    		0.469"1.125"0.056" to 0.071"Not Rated3,000—Off-White0000000000000
    1/2"
    		0.531"1.250"0.090" to 0.112"Not Rated3,000—Off-White0000000000000
    9/16"
    		0.594"1.469"0.090" to 0.112"Not Rated3,000—Off-White0000000000000
    5/8"
    		0.656"1.750"0.090" to 0.112"Not Rated3,000—Off-White0000000000000
    3/4"
    		0.812"2.000"0.090" to 0.112"Not Rated3,000—Off-White00000000000000
    7/8"
    		0.938"2.250"0.146" to 0.174"Not Rated3,000ASME B18.21.1Off-White00000000000000
    1"
    		1.062"2.500"0.146" to 0.174"Not Rated3,000ASME B18.21.1Off-White00000000000000
    M2
    		2.6 mm6.0 mm0.6 mm to 0.9 mmNot Rated3,000ASME B18.22MOff-White0000000000000
    M3
    		3.6 mm10.0 mm0.8 mm to 1.2 mmNot Rated3,000ASME B18.22MOff-White0000000000000
    M4
    		4.8 mm12.0 mm1.0 mm to 1.4 mmNot Rated3,000ASME B18.22MOff-White0000000000000
    M5
    		5.6 mm15.0 mm1.2 mm to 1.8 mmNot Rated3,000—Off-White0000000000000
    M6
    		6.8 mm18.8 mm1.2 mm to 1.8 mmNot Rated3,000—Off-White0000000000000
    M8
    		9.0 mm25.4 mm1.6 mm to 2.3 mmNot Rated3,000ASME B18.22MOff-White0000000000000
    M10
    		11.0 mm28.0 mm2.0 mm to 2.8 mmNot Rated3,000ASME B18.22MOff-White0000000000000
    M12
    		13.4 mm34.0 mm2.5 mm to 3.5 mmNot Rated3,000ASME B18.22MOff-White0000000000000
    M14
    		15.4 mm39.0 mm2.5 mm to 3.5 mmNot Rated3,000ASME B18.22MOff-White00000000000000
    M16
    		17.4 mm44.0 mm3.0 mm to 4.0 mmNot Rated3,000ASME B18.22MOff-White00000000000000
    M20
    		22.0 mm50.0 mm3.5 mm to 4.6 mmNot Rated3,000ASME B18.22MOff-White00000000000000

    Insulating Sleeve Washers

    Cover screw threads to stop electrical current in its tracks and prevent short circuits. These washers create a barrier between the screw threads and the mating surface when mounted in through holes. This barrier also extends the life of your assembly by preventing galvanic corrosion, which is when two different metals rust more quickly due to contact with each other.
    Flat Edge
    Image of Product. Front orientation. Insulating Washers. Insulating Sleeve Washers, Flat Edge.
    The flat edge distributes weight evenly to take pressure off screw heads.
    Extra-High-Temperature Ceramic—Our most heat-resistant washers and the best electrical insulators. These won't melt or become brittle at blistering temperatures up to 1,700° F, making them perfect for ovens, kilns, and furnaces. Ceramic may crack or dent if subjected to hard bumps, however, so these washers are not recommended for high-vibration applications.
    Sleeve
    Temp.
    Range
    For Screw
    Size
    Ht.
    OD
    ID
    OD
    Thk.
    Overall
    Ht.
    Min.
    Max.,
    ° F
    Color
    Pkg.
    Qty.
    Pkg.
    Extra-High-Temperature Ceramic
    No. 6
    		0.062"0.281"0.150"0.500"0.125"0.187"Not Rated1,700Off-White5000000000000000
    No. 6
    		0.250"0.281"0.150"0.500"0.187"0.437"Not Rated1,700Off-White500000000000000
    No. 8
    		0.062"0.406"0.175"0.625"0.125"0.187"Not Rated1,700Off-White500000000000000
    No. 8
    		0.250"0.406"0.175"0.625"0.218"0.468"Not Rated1,700Off-White500000000000000
    No. 10
    		0.062"0.468"0.200"0.750"0.156"0.218"Not Rated1,700Off-White500000000000000
    No. 10
    		0.250"0.468"0.200"0.750"0.218"0.468"Not Rated1,700Off-White500000000000000
    1/4"
    		0.062"0.593"0.265"0.875"0.188"0.250"Not Rated1,700Off-White500000000000000
    1/4"
    		0.250"0.593"0.265"0.875"0.250"0.500"Not Rated1,700Off-White500000000000000
    M2
    		2.500 mm3.000 mm2.100 mm4.200 mm1.500 mm4.000 mmNot Rated1,700Off-White10000000000000
    M3
    		1.500 mm4.000 mm3.100 mm6.200 mm1.500 mm3.000 mmNot Rated1,700Off-White10000000000000
    M3
    		3.500 mm4.000 mm3.100 mm6.200 mm1.500 mm5.000 mmNot Rated1,700Off-White10000000000000
    M3
    		7.500 mm4.000 mm3.100 mm6.200 mm1.500 mm9.000 mmNot Rated1,700Off-White10000000000000
    M4
    		3.000 mm6.000 mm4.100 mm8.400 mm1.500 mm4.500 mmNot Rated1,700Off-White10000000000000
    M4
    		5.000 mm6.000 mm4.100 mm8.400 mm1.500 mm6.500 mmNot Rated1,700Off-White10000000000000
    M5
    		3.000 mm7.000 mm5.100 mm10.200 mm2.000 mm5.000 mmNot Rated1,700Off-White10000000000000
    M5
    		5.000 mm7.000 mm5.100 mm10.200 mm2.000 mm7.000 mmNot Rated1,700Off-White10000000000000
    M6
    		4.000 mm8.000 mm6.100 mm12.200 mm2.000 mm6.000 mmNot Rated1,700Off-White10000000000000
    M6
    		10.000 mm8.000 mm6.100 mm12.200 mm2.000 mm12.000 mmNot Rated1,700Off-White10000000000000
    M8
    		4.000 mm10.000 mm8.100 mm14.200 mm2.500 mm6.500 mmNot Rated1,700Off-White10000000000000
    M8
    		8.000 mm10.000 mm8.100 mm14.200 mm2.500 mm10.500 mmNot Rated1,700Off-White10000000000000
     

    Insulating Cup Washers

    Image of Product. Front orientation. Insulating Washers. Insulating Cup Washers.
    Cover screw heads or nuts to block electrical current and prevent short circuits. These washers isolate fasteners from sensitive surface-mounted components, such as capacitators and transistors on printed circuit boards. They also extend the life of your assembly by preventing galvanic corrosion, which is when two different metals rust more quickly due to contact with each other.
    Extra-High-Temperature Ceramic—Our most heat-resistant washers and the best electrical insulators. These won't melt or become brittle at blistering temperatures up to 1,700° F, making them perfect for ovens, kilns, and furnaces. Ceramic may crack or dent if subjected to hard bumps, however, so these washers are not recommended for high-vibration applications.
    Temp.
    Range
    For Screw
    Size
    ID
    OD
    Cup
    ID
    Inside
    Dp.
    Thk.
    Overall
    Ht.
    Min.
    Max.,
    ° F
    Color
    Pkg.
    Qty.
    Pkg.
    Extra-High-Temperature Ceramic
    No. 4
    		0.130"0.440"0.250"0.125"0.100"0.225"Not Rated1,700Off-White100000000000000
    No. 6
    		0.160"0.500"0.312"0.150"0.100"0.250"Not Rated1,700Off-White10000000000000
    No. 8
    		0.180"0.560"0.375"0.170"0.100"0.270"Not Rated1,700Off-White10000000000000
    No. 10
    		0.200"0.625"0.437"0.190"0.100"0.290"Not Rated1,700Off-White10000000000000
    1/4"
    		0.260"0.750"0.531"0.250"0.100"0.350"Not Rated1,700Off-White10000000000000
     

    Electrical-Insulating Unthreaded Spacers

    Image of Product. Front orientation. Spacers. Electrical-Insulating Unthreaded Spacers.
    Stop electrical current in its tracks—these nonconductive spacers prevent it from passing through your components. They’re often used to insulate circuit boards and enclosures.
    Ultra-High-Temperature Grade L5 Ceramic—Our most heat-resistant spacers, even at blistering temperatures up to 1700° F. However, they may crack or dent if subjected to hard bumps and vibrations.
    Lg.
    For Screw
    Size
    ID
    Dielectric Strength,
    V/mil
    Temp. Range,
    ° F
    Pkg.
    Qty.
    Pkg.
    Ultra-High-Temperature Grade L5 Ceramic
     
    1/4" OD
    3/16"No. 3
    		0.115"27550 to 1,700100000000000000
    3/16"No. 4
    		0.140"27550 to 1,70010000000000000
    1/4"No. 3
    		0.115"27550 to 1,70010000000000000
    1/4"No. 4
    		0.140"27550 to 1,70010000000000000
    3/8"No. 3
    		0.115"27550 to 1,70010000000000000
    3/8"No. 4
    		0.140"27550 to 1,70010000000000000
    1/2"No. 4
    		0.140"27550 to 1,70010000000000000
    5/8"No. 4
    		0.140"27550 to 1,70010000000000000
    3/4"No. 4
    		0.140"27550 to 1,70010000000000000
     
    3/8" OD
    1/4"No. 8
    		0.192"27550 to 1,70010000000000000
    3/8"No. 8
    		0.192"27550 to 1,70010000000000000
    1/2"No. 8
    		0.192"27550 to 1,70010000000000000
    3/4"No. 8
    		0.192"27550 to 1,70010000000000000
    1"No. 8
    		0.192"27550 to 1,70010000000000000
     
    1/2" OD
    3/8"No. 10
    		0.250"27550 to 1,70010000000000000
    1/2"No. 10
    		0.250"27550 to 1,70010000000000000
    3/4"No. 10
    		0.250"27550 to 1,70010000000000000
    1"No. 10
    		0.250"27550 to 1,70010000000000000
     
    back to top