Outside tap - fibre washers?

[Part timer]

A quick issue regarding replacing an outside tap. My present one has packed in for good (turn it to open and it doesn't actually open anymore). I have ripped out the check valve about 3 years ago when it last stopped working (don't need a check valve for my uses). Bought Screwfix part 16949 "Outside Tap Without Check Valve". Claims to be 1/2" and BS 1010. My problem is it doesn't line up (in 12 o'clock position) like the old one does when fully screwed in. Would I be looking at fibre washers to achieve this vertical position when it's fully tightened and are these a common, standard size? Out of interest, where is the 1/2" measurement measured?

Thanks

J.

[Rod]

I have just fitted a similar outside tap myself. Exactly the same problem - tap wanted to be at about 06:00 (rather than 12:00, so to speak). I just wrapped a wodge of PTFE tape round the thread and retightened it. Repeated until it stopped just before the right position when hand tight. Final touch with spanner aligned it nicely.

[Bob Minchin]

Use PTFE tape and or washers. Should be able to get them from plumbers merchants. There is no dimension of a 1/2" bsp thread that measures 1/2" It is based on the bore of thick wall iron pipe around the time the thread was defined. Pipe is thinner wall now. Thread is 14 tpi so you can work out what thickness of washer you need for a given number of degrees of rotation. It works out to be 0.005mm per degree with less than 1% error hth

Bob

[TMC]

It does amaze me how primitive plumbing fittings are

Surely it cannot be beyond the resources of mankind to design an outside tap that will both fix to the wall and align correctly

I use a washer made of a scrap of lead flashing and tighten the tap until it aligns then trim off the excess lead

Tony

[Bob Mannix]

That's how you are meant to fit them - not suprising it worked!

[Rod]

Aahhh, but in the old days, I would have got a little bit of hemp and "woven" it into a washer, smeared Boss White (original, smelly) on it and then done it up.

(That missed out the washer that came out too small, followed by three that were too big. And cleaning off the Boss White from the tap, the fitting, the pipe and, eventually, my hands. And spending the evening wondering where that funny smell was coming from. :-) )