3/8 hosetail x 3/8 Barb Not Same Bore As Other 3/8 Fitttings

  1. Pollys13

    Pollys13 Member

    Messages:
    333
    Location:
    Wiltshire UK
    I have a pot with a 3/8 ball valve, dropping down into an equal T with a 3/8 bore. Also a pair of regulators with 3/8 ports, hose with ID of 3/8, elbows with 3/8 bore, piping with 3/8 bore.That said the 3/8 male hosetails with 3/8 barb. The barb is much smaller than a 3/8 bore, have I missed something here? I'm thinking the smaller bore could cause a bottleneck to the grit blasting hose and a restriction in the airflow in airline hose? Not made mistake with size of hosetails, they are 3/8 thread x 3/8 barb.
    Any advice appreciated.
    Cheers.
     
  2. brightspark

    brightspark Member

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    yarm
  3. carbon

    carbon Member

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    1,267
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    S. Glos. U.K
    3/8" bsp is approx 16mm od for male thread hosetail should be 3/8" or 10mm od sorry to mix metric and imperial
     
    brightspark likes this.
  4. timgunn1962 Member

    Messages:
    80
    Location:
    Lancashire UK
    3/8 BSP is the thread that would be cut on the outside of a pipe with a 3/8" bore and is about 16.7 mm major diameter. A 3/8 hose has a bore of 3/8".

    The hosetail has a barbed section that will push into 3/8" bore hose, but the barbed section needs to have some wall thickness, so its ID will be significantly less than 3/8" and it will cause the potential bottleneck mentioned by the OP. In most cases, the length of the restriction is short enough not to dramatically affect the airflow through the overall system. In the unlikely event it does cause a problem, increasing the hose size and using appropriate hosetails with a bigger ID will get around the problem.
     
  5. Pollys13

    Pollys13 Member

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    333
    Location:
    Wiltshire UK
    Thanks for replies.
     
  6. Pollys13

    Pollys13 Member

    Messages:
    333
    Location:
    Wiltshire UK
    I have a pinch valve, the housing has a 3/4 female NPT port, the actual pinch valve sleeve has a bore of 3/8. I've fitted a 3/4 NPT male x 1/2 female bsp into the housing.

    " increasing the hose size and using appropriate hosetails with a bigger ID "

    The grit air mix will be coming through the pinch valve sleeve, into the hose that goes into cabinet, through a fitting ( have ordered a 14mm x 15mm thin spanner to remove the fitting to find out what it is, as an American cabinet, will be a NPT fitting ) I feel is inportant to maintain a continuity of grit flow through the sleeve, minimising any possibility of bottlenecks. If a hosetail won't do the job, Using an adapter fitting, then, I'm thinking of an extended, say 50mm long 3/8 nipple which will have an actual bore size of 3/8, hot water the hose, push it over the threads, then crimp, clamp hose on the smooth part of the nipple? Hose in cabinet is 3/8 bore.
    Any help advice appreciated.
    Thanks.
     
  7. brightspark

    brightspark Member

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    I made my own barb for the outlet from the tee piece out of steel the brass ones will work but will wear out with regular use the air one other side of the tee is brass as that's only air
     
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  8. Pollys13

    Pollys13 Member

    Messages:
    333
    Location:
    Wiltshire UK
    OK. Realized a 3/8 extended nipple the od, no way will get that in a 3/8 bore hose. A 3/8 bsp Male x 1/2 Hosetail any idea of what the through bore of that would be?
     
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