McMaster-Carr logo
    Filter by
    Drive Style
    Industrial Info Snippet
    System of Measurement
    Thread Size
    Industrial Info Snippet
    Fastener Head Type
    Head Diameter
    Attribute Image
    Tip Type
    Driver Style
    Rounded Head Style
    Tip Style
    Shank Type
    Thread Spacing
    Industrial Info Snippet
    Thread Direction
    Head Height
    Attribute Image
    DFARS Specialty Metals
    Industrial Info Compare
    Export Control Classification Number (ECCN)
    Industrial Info Snippet
    U.S.–Mexico–Canada Agreement (USMCA) Qualifying
    Rounded Head Profile
    Hardness
    Specifications Met
    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)
    6 Products

    Tamper-Resistant Asymmetrical-Drive Stainless Steel Button Head Screws

    Image of Product. Front orientation. Contains MultipleImages. Rounded Head Screws. Tamper-Resistant Asymmetrical-Drive Stainless Steel Button Head Screws.
    These screws have a unique drive that's only available from McMaster-Carr. The drive, which has a security pin in it, only turns with an asymmetrical driver. Made of stainless steel, they won't rust or corrode when exposed to moisture and chemicals. The button head looks similar to a pan head, but it's lower and more compact, taking up less space.
    Length is measured from under the head.
    18-8 Stainless Steel—The choice for wet and outdoor environments, these screws won't rust. However, they don't hold up to the harsh chemicals that 316 stainless steel can.
    Screws
    Screwdriver Bits
    Head
    Lg.
    Dia.
    Ht.
    Threading
    Tensile Strength,
    psi
    Specs.
    Met
    Pkg.
    Qty.
    Pkg.
    Each
    18-8 Stainless Steel
     
    1/4"-20
    1/2"0.437"0.132"Fully Threaded70,000ASME B18.3599355A30500000099355A624000000
    3/4"0.437"0.132"Fully Threaded70,000ASME B18.3599355A3110000099355A62400000
    1"0.437"0.132"Fully Threaded70,000ASME B18.3599355A3140000099355A62400000
    1 1/4"0.437"0.132"Fully Threaded70,000ASME B18.3599355A3170000099355A62400000
    1 1/2"0.437"0.132"Fully Threaded70,000ASME B18.3599355A3200000099355A62400000
     

    Asymmetrical Bits

    Image of Product. Front orientation. Screwdriver Bits. Asymmetrical Bits.
    Access restricted equipment secured with asymmetrical screws. These bits have a unique drive that's only available from McMaster-Carr, so they're a favorite for thwarting thieves.
    Hex Shank—Also known as insert bits, these snap into hand tools. If you want to use them with power tools, attach a bit adapter (not included).
    Steel—Best for dry environments, since moisture will cause these bits to rust.
    Drive
    Size
    Overall
    Lg.
    Material
    Each
    For Hand Tools
     
    1/4" Hex Shank Size
    U251"Steel99355A624000000
     
    back to top