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Brass Screw Sizes

Discussion in 'Wood / Woodwork / Carpentry' started by yottie, 24 Sep 2019.

  1. yottie

    yottie

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    Am replacing old brass wood-screws for new equivalents. The old ones seem the same size as M6 steel screws but M6 present brass screws appear to be a lot bigger. Are brass screws measured differently? I need M6 steel screws in brass !!
     
  2. JobAndKnock

    JobAndKnock

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    Well for a start M6 is an engineering size and nothing to do with wood screws. Wood screws were/are generally sized in the old Imperial sizes with steel and brass screws being sized identically, but there are approximate equivalent sizes in metric, viz:

    #6 = 3.5mm
    #8 = 4.0mm
    #10 = 5.0mm
    #12 = 6.0mm

    I'd emphasise that these are approximate equivalents, not exact; for example the equivalent to #12 is stated by some sources to be 5.5mm (a non-existent size AFAIK). Best approach is to try and get yourself some old stock Nettlefolds screws in an appropriate size - if nothing else I find them harder and stronger than many modern brass screws. Failing that be prepared to repilot and re-countersink to take modern metric screws. As to screw head sizes, these have always varied in size from manufacturer to manufacturer and still do
     
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  3. foxhole

    foxhole

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    Modern brass screws are often sh ite due to weak mix of metals ( cheaper) very shiny while older quality screws are much darker .
    I often use gold screws where strength is required to replace brass screws .
     
    Last edited: 24 Sep 2019
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  4. Munroist

    Munroist

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    and check what you are buying with a magnet
     
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  5. JobAndKnock

    JobAndKnock

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    I have to agree that passivated steel screws ("gold screws") look similar to aged brass and are often a better choice as they are far stronger (as well as being PZD head) unless you are dealing with antiques or some high-tannin woods like oak, mahogany or walnut
     
  6. foxhole

    foxhole

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    Brass isn’t magnetic .
     
  7. EddieM

    EddieM

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    Wasn't that the point?
     
  8. Nozzle

    Nozzle

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    Since you're using terms like "M6" it rather sound to me like it's a machine screw you're after, not a wood screw as some of the above posts suggest.

    There's a chance you need to be looking at BA sized screw

    Nozzle
     
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  9. foxhole

    foxhole

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    What point?
     
  10. EddieM

    EddieM

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    That if you're buying brass screws, make sure they're not magnetic otherwise they're not brass?
     
  11. foxhole

    foxhole

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    It says brass on the box.
     
  12. yottie

    yottie

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    Yes I'm sorry about the "M" (must have been thinking about the Motorway!) These screws are to replace existing slot heads on solid brass carpet dividers. No 6 steels fit the slots, but on ebay etc the brass sizes seem to be referred to differently.
     
  13. SFK

    SFK

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  14. rsgaz

    rsgaz

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    These are the exact sizes, not rounded up/down at all...

    upload_2019-9-25_11-2-49.png

    See how the inches column goes up by 13 thou' each step.
     
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  15. yottie

    yottie

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    Most useful ebay site and size chart, many thanks.
     
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