Hosepipe for pressure washer etc, but nothing seems to fit the outside tap?.

[Profpointy]

Fair point. It'll be the 3/4inch standard size then.

I very much doubt it, but it is conceivable

 

[Dadam]

The BSP size does not measure the thread size
https://www.stevensonplumbing.co.uk/bspt.html
1/2" BSP is about 21mm across the threads

 

[Alex321]

I'd go for the first one I listed in my previous post, as that will fit both 3/4 and 1/2 inch, having the insert for the latter.

 

[Kingfisher101]

I'd go for the first one I listed in my previous post, as that will fit both 3/4 and 1/2 inch, having the insert for the latter.

Thanks, I can get this from the local Screwfix, so I'm going to order this and if it doesnt fit I'll return it.

 

[newts]

The advertisement will usually say 1/2“ bib tap, this refers to inlet side of the tap that screws onto the supply side which is 1/2" BSP male thread (approx 20mm diameter). The outlet end has a 3/4" BSP male thread (approx 25mm diameter), often it will include a screw on spigot to attach a hose. Usually you'd throw away the spigot & replace it with a 3/4" connector >quick realease hose connector like this;-
https://www.screwfix.com/p/hozelock-1-2-3-4-threaded-tap-connector/52973

This adapter includes also includes a reducing bush down to 1/2" for other applications where a bib tap might not be used as the isolation point.
I've never seen a outside tap with 1/2" BSP on the outlet side in my 40+ years in the building trades.

 

[Kingfisher101]

Thank You, I'm going to order this metal version. https://www.screwfix.com/c/outdoor-gardening/hose-tap-connectors/cat11820002
Right I've ordered it and will collect it tomorrow. I'll let everyone know if its fitted or not and thank you again for helping.

 

[Electric_Andy]

Just to add, if you need to use it without a tap just to get by, the bucket method works fine if you fill the hose with water first. It won't usually suck through an entire empty hose pipe unless you prime it with water first

 

[presta]

some pictures of mine, which is a 1/2" BSP. As you can see the external diameter is a touch over an inch

Er, no it isn't, that's 3/4" BSP:

can we have an agreement regarding which size I should buy

Here's the BSP page from my Machinery's Handbook, 1/2" BSP is 0.825" OD, 3/4" BSP is 1.041" OD, a ruler will tell you which one you need:

 

[Profpointy]

Er, no it isn't, that's 3/4" BSP:


Here's the BSP page from my Machinery's Handbook, 1/2" BSP is 0.825" OD, 3/4" BSP is 1.041" OD, a ruler will tell you which one you need:

View attachment 718549

Whilst I do agree (I had the same problem as the OP when I bought my fittings) , but the trouble is the fitting I bought was sold as 1/2" BSP even though it is measured as an inch and a bit across the theeads; Presumably because of the intended hose pipe size.

 

[Kingfisher101]

https://www.hozelock.com/how-to-mea.../#:~:text=So when you measure the,be 1/2″ BSP.
Theres this which shows how to measure it and I think the adaptor wont fit my thread as mine measured 23mm across the bottom. If it doesnt then I will keep the adaptor and get someone to fit me a new outside tap this next week or so.

 

[presta]

mine measured 23mm across the bottom

Assuming that's across the outside of a male thread, that might be 5/8" BSP, in which case I'd give up and fit a new tap. You could try your washing machine hose on it, if that fits it's 3/4" BSP.

 

[Profpointy]

Assuming that's across the outside of a male thread, that might be 5/8" BSP, in which case I'd give up and fit a new tap. You could try your washing machine hose on it, if that fits it's 3/4" BSP.

I doubt it's 5/8 BSP on a water tap as that would be very unusual.

As an aside the superior type of SCUBA cylinder to regulator connectionis a DIN fitting (ie a German standard). The thread for that is surprisingly 5/8 BSP. The DIN version is decidedly better than the older A clamp fitting

 

[presta]

I doubt it's 5/8 BSP on a water tap as that would be very unusual.

Yes, it doesn't sound very likely to me either. I wondered if he was measuring the inside diameter of the female thread instead, but 23mm still doesn't match either of the standard sizes. There are some non-standard threads about of course, I recall years ago one of the compression fittings manufacturers was using a non-standard thread instead of 1/2" BSP. Might have been Conex IIRC.

 

[Profpointy]

Yes, it doesn't sound very likely to me either. I wondered if he was measuring the inside diameter of the female thread instead, but 23mm still doesn't match either of the standard sizes. There are some non-standard threads about of course, I recall years ago one of the compression fittings manufacturers was using a non-standard thread instead of 1/2" BSP. Might have been Conex IIRC.

I do sympathise as I had the same rigmarole myself. Despite have a decent vernier, and a fair if amateur grasp of such things, it didn't seem to correspond to what was listed, and as I mentioned, in the end I bought a 1/2" fitting even though the actual thread corresponded to 3/4" BSP. Presumably, and bizzarely the fitting was rated for the hose size and the tap's pipe size rather than the actual thread it went into

 

[Kingfisher101]

Hi, I just measured across the bottom of the thread, it was definitely around 23mm-24mm. If this adapter doesn't fit I'll just get a plumber to fit the newest version of an outside tap and I'll make sure the attachment fits as well.
It is bad when you cant get a hosepipe to fit as it a struggle with washing down the patio etc with a watering can.