3/4" BSP sizing

tommiejoie

I want to fit a garden hose connector to a circulation pump valve. Both the hose connector and the valve compression threads are listed as 3/4" BSP. I had expected these would fit well together, but the plastic tap connector internal thread diameter is actually smaller than the brass valve external thread diameter.

What am I missing here, how can these two 3/4" BSP be different sizes and not fit together?

CelticRambler

The product info I'm seeing for that Draper reference says you've got 3/4" and 1/2" fittings, presumably a two-in-one by means of the white insert. Are you trying to fit the smaller 1/2" white ring to the tap, or is it the grey one that has a smaller ID?

tommiejoie

The white reducer has been removed. I am working the the 3/4" part only., the grey one.

10-10-20

Wondering if this is a UK product and the threads are UK spec and not Irish…?

tommiejoie

Never heard of a difference of UK vs Irish spec, except for metric and imperial, but still, both parts are marked as 3/4" BSP.

standardg60

Discussed on another thread recently. The tap fitting is most likely a 'farmers tap' size, which is actually 7/8ths of an inch.

https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://www.raygrahams.com/products/157464-brass-farmers-tap-connector.aspx&ved=2ahUKEwjP_5jRhqGGAxU6WkEAHbGzCC4QFnoECBUQAQ&usg=AOvVaw3M_dJyWaM9g6oGWEgVJ5up

tommiejoie

Never heard of farmers tap before, but 7/8" sounds possible. Thanks for the link.

tommiejoie

https://www.boards.ie/discussion/comment/122168892#Comment_122168892

Perfect fit and compatible with hozelock connectors. Problem solved, thanks!