What size Coupling/Thread ?

  1. demented Member

    Messages:
    53
    UK
    Anyone know the Coupling size of both sides of Clarke Ranger Compressor Shut of Valve/Tap (shown below) which, I want to replace but with a different Valve/Tap.
    IMG_20190606_111130360.jpg
    Within the Clarke User Manual it mentions 1/4BSP; so, I understood the smaller Male thread to be 1/4 BSP and the bigger end 3/8 BSP ?
    The Male PCL Snap Connector, I assumed had 3/8 BSP male end ?
    IMG_20190606_111308341.jpg

    I've bought a 3/8 BPS double Female Shut off Valve and a Male 3/8 to 1/4 reducer, which are all too big; so trying to clarify size required before I re-order.

    Any idea ?
     
    Last edited: Jun 6, 2019
  2. Ashley Burton

    Ashley Burton Member

    Messages:
    2,314
    Location:
    Northamptonhire
    BSP Thread Sizes = Actual sizes in Metric
    1/4 =11.8mm
    3/8 = 15.25 mm
    1/2 = 19.00mm

    Hope that helps
     
    roofman and Hopefuldave like this.
  3. demented Member

    Messages:
    53
    UK
    Thanks for your reply and yeah, it's good to know the actual thread sizes and will come in handy no doubt; but it's the BSP size I'm trying to identify.

    Thanks again
     
  4. MoreWellie Member

    Messages:
    983
    Location:
    Bedfordshire, UK
    @demented maybe you should read Ashleys post again

    he has given you the metric equivalents for the outside threads of the common BSP connection sizes.

    if you slap a mic (or a ruler) across the threads on your fittings these should help you identify your BSP thread sizes
     
  5. carbon

    carbon Member

    Messages:
    1,117
    Location:
    S. Glos. U.K
    @Ashley Burton the sizes that you have quoted are tapping drill sizes rather than the male thread dimensions. Look for a male bsp thread chart for metric equivalents
     
  6. demented Member

    Messages:
    53
    UK
    Thanks for replies and much appreciated..
    As for measuring; the new valve and reducer are sealed in semi transparent plastics bags and as I'll be returning, either for a refund or exchange, I don't won't to open the bags.
    Although I have photos on my phone, the original shut off valve and snap connectors are with the compressor in the garage and not with me.

    I think I've worked it out though.
    The smaller thread on the original shut off valve, dipicted in the photo and on the left, is actually 1/8 BSP.

    So I require a 1/4 to 1/8 BSP Male Reducer and a Double Female 1/4 BSP Shut Off Valve.
     
  7. Ashley Burton

    Ashley Burton Member

    Messages:
    2,314
    Location:
    Northamptonhire
    Yes you are correct!

    My mistake, But those measurements will give you a good enough idea of which is which
     
  8. melle Member

    Messages:
    285
    Location:
    Bath UK/ Dublin IRL
    Yes, that's very common on smallish compressors. I replaced a similar shut off valve with a ball valve recently, I can take a pic later if that helps.
     
  9. demented Member

    Messages:
    53
    UK
    Yeah, that'll be good, if not too much trouble.

    Although, I've just ordered a new 1/4 Female shut off valve and a 1/8 male reducer from Rs Components.
     
  10. melle Member

    Messages:
    285
    Location:
    Bath UK/ Dublin IRL
    I've installed a ball valve-connector assembly like below on a few compressors, this one had a 1/8 BSP outlet on the regulator. I make sure connectors and valve levers don't stick out, so cables, trousers etc. won't catch on them. I also replace the "drains" (or crud collectors rather) with 3/8 ball valves and a hose barb with about 1' garden hose, and add a cheap car oil filter as an intake filter.

    For below assembly I used male/ female 1/8 BSP elbow> male/ male 1/8-1/4 adapter> female/male 1/4 ball valve> female 1/4 euro connector. I normally use whatever I have in the workshop, but this compressor followed me home recently from @Wozzaaah HQ, so I had to buy new fittings as I couldn't find any in the fridge!

    [​IMG]
    [​IMG]
     
  11. merckx Member

    Messages:
    46
    Newcastle
    Have you noticed much of an improvement in reducing the compressor noise with the oil filter?
     
  12. brightspark

    brightspark Member

    Messages:
    26,349
    Location:
    yarm
    pretty restricted air supply with those size fittings :)
     
    eil likes this.
  13. melle Member

    Messages:
    285
    Location:
    Bath UK/ Dublin IRL
    No, not on direct drive compressors. The pistons/ rings love it though!

    This one, as many compressors, came with a 1/8 BSP outlet from the factory, the original tap had a bore of about 4-5mm I think. I don't see how my fittings, which all have a bigger bore, reduce the air supply?
     
  14. brightspark

    brightspark Member

    Messages:
    26,349
    Location:
    yarm
    there a poor idea from the factory . specially on air tools .the outlet filter regulator is small bore . its far better taking a larger bore filter reg directly off the end of the tank if there is a plug fitted which most have heres one of mine the other end of the tank has an outlet as well fitted with a half inch bsp filter regulator
     
    • DSCF0958 (1).JPG
  15. melle Member

    Messages:
    285
    Location:
    Bath UK/ Dublin IRL
    I've never found the small bore outlets too restrictive for what I use air compressors for. I have a different compressor for my blast cabinets though with a 3/8" bore outlet iirc (could even be 1/4"), works just fine.
     
  16. brightspark

    brightspark Member

    Messages:
    26,349
    Location:
    yarm
    I use 15 mm bore pipe on my small blasting gear and 3/4 on the larger one. 3/8 th will be ok on the 3mm jet pot but 1/4 is noticeably more restricted on cfm and loss of power
     
  17. melle Member

    Messages:
    285
    Location:
    Bath UK/ Dublin IRL
    I only have two small cabinets.

    [​IMG]
     
    8ob likes this.
  18. brightspark

    brightspark Member

    Messages:
    26,349
    Location:
    yarm
    they will be fine on suction guns. but pressure pots use a fair bit of cfm :)I have a suction gun as well . used an original one as a pattern and cast it in aluminium and knocked one up :laughing:
     
    • DSCF1020 (1).JPG
    Last edited: Jun 8, 2019
  19. melle Member

    Messages:
    285
    Location:
    Bath UK/ Dublin IRL
    I believe you, but that's not very relevant here as we're discussing small DIY compressors. ;)
     
    brightspark likes this.
  20. demented Member

    Messages:
    53
    UK
    melle.... Thanks for the photos and the insight, food for thought, I didn't think of adding the elbow; will now.
    Yeah, current outlet protrudes too much, hence why I'm replacing, due to similar experience as yourself.
     
Advertisements