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Where can I buy 1/4-20 UNC bolts?

Discussion in 'General Discussion' started by MikeHunt79, Jul 6, 2011.

  1. MikeHunt79

    Capodecina

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    I know we're supposed to be metric now, but I've got something from the US which needs '1/4-20 UNC bolts' to mount it according the the manual.

    Now as I grew up in the 80's, I have no idea what 1/4-20 UNC bolts are or where to get them.

    I've tried searching on Screwfix and Toolstation, but these only seem to offer the usual M3, M6, M10, etc. bolts an no imperial sized bolts.

    Does anyone know where I can get some of these bolts from at all?

    Thanks.
     
  2. Pudney

    Mobster

    Joined: Sep 6, 2005

    Posts: 4,445

    Location: Essex

  3. Simon

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    Location: Berks / Moscow

    edit, nm wrong company.
     
  4. MikeHunt79

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    Ok, I've just tried a normal M6 bolt that I got from screwfix and it went in half a turn and then stopped. I can only a assume the usual M6 bolts are the right diameter but the wrong thread pitch?
     
  5. c@tbyte

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  6. Pudney

    Mobster

    Joined: Sep 6, 2005

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    Location: Essex

    I googled it and exhausted my knowledge on this subject. If you want help with tax I can do that :D

    Although it would appear that the thread is the issue, I just have no idea how that works for metric bolts, screwfix doesn't seem to specify.
     
  7. TaKeN

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  8. PhillyDee

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    Trust me, imperial sizes are still used a lot. America uses those sizes, as do aerospace and the oil and gas industry. 1/4" is 6.35mm, and 20 is the teeth per inch (1.27mm pitch).
     
  9. DirtyJester

    Caporegime

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    Posts: 25,662

    How many you need and what size and type (ie. cap head / mushroom etc etc) ?
     
  10. MikeHunt79

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    Thanks, they are stainless too which is nice, I can't see any mention of 20 (TPI) on there however, an I right in assuming that most 1/4 UNC bolts have 20 TPI>

    I'm pretty sure normal M6 bolts that screwfix/toolstation/B&q/etc supply have a 1mm pitch, which would be around 25TPI, so that explains why my M6 bolt didn't fit!

    After a little more googling it does seem that many camera tripods use the same thread, so I guess they're more common than I first thought.
    Nice, that 2nd link seems to definitely be the right size and they even specify the spanner I need also. :)

    Gotcha, afaik normal M6 bolts are 1mm pitch so I guess that's why my bolt didn't fit.

    I need 6, either normal cap head or mushroom/button head, they don't need to be mega strong, as long as they can hold 10kg or so each.
     
  11. c@tbyte

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    All 1/4 UNC are 20 TPI
    If you needed finer threads you'd use UNF (Unified Fine).

    There are all sorts of threads:
    UN Fine and Coarse
    Metric Fine and Coarse
    BSF, BSW, BSP, BA, etc. The list goes on.
    Being in engineering I've used most of them at one time or another.
     
  12. Westyfield2

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    You not got a local place you can go to? In Bath I always use Avery Knight & Bowlers Ltd (James Street West, behind Green Park Station). Haven't yet found a bolt they can't supply!
     
  13. MikeHunt79

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    ^ I do know of a few smaller (non chain) shops in and around Bristol, so now I know a little more about what I'm after I'll have to pop in and have a look. :)
    Ok, that makes sense, I was searching places like ebay for '1/4 UNC 20' and mainly getting things like taps and dies in my results.

    After searching again for '1/4 UNC' I now have plenty of bolts to choose from, in fact item 320717773234 looks ideal, thanks.

    I can see how things are far simpler if only metric threads are used, I remember talking to someone about an old motorbike that featured many different kinds of threads (Whitworth, etc.), that must have been a bit of a headache to work on. :eek:
     
  14. DirtyJester

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    Hi Mike I'm pretty sure I can sort you out but I'm not back to work till Sat. week.
     
  15. PhillyDee

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    Simpler maybe, but certain threads have different uses. Though sometimes I do wonder about the people who do the designing, I work in manufacturing, and it is a lottery as to what thread they just pluck out of thin air sometimes! Nearly identical jobs can have completely different ones! Just makes it a PITA.
     
  16. DirtyJester

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    Mike sent ya message via Trust.
     


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