IRON TO COPPER CONNECTION: help!!

[crashanova]

I am installing new pipes feeding a new basin and existing bath by connecting copper runs to the existing iron pipework (there was lead pipe running from the iron to the bath/basin before).

So far it has gone well: I used a 1/2in female thread to 15mm compression connectors for the basin feeds - no probs connecting to the iron. I used a 3/4in female thread to 22mm for the hot bath - again, no probs.

The cold bath connection looked bigger judging from the existing nut so I was half expecting it not to be a 3/4inch FI connection (I was right - the connector was too small). So naturally I assumed it needed a 1inch female... I tried this but the diameter is too big by a long way!

This is apparently neat standard BSP iron/galavised steel pipework we are looking at from, I think, the 50s/60s. Does anyone have any ideas what size this threaded male pipe end must be? That is, what female connector do I need (obviously not 3/4 or 1in)? My plumber's merchant is at a loss!

ANYONE HELP??

Thanks.

PS I cannot accurately measure the diameter due to awkward position!

 

[bobxx]

Probably 7/8 BSP 14 threads to inch

 

[Nige F]

Male pipe end? you must`ve left part of the lead union on And I`ve never heard of 7/8 pipe in 36 years @ the game I even wiped joints on lead tails @ college in the 70`s....why not leave the lead tail on? they are hand bendable

 

[bobxx]

Pipe is not 7/8 Pipe thread is 7/8 BSP 30.2 m/m diameter
I turned fittings 50 yrs ago and there is also 1/1/8 BSP thats the size of thread on most gas meters.Have a look at.
http://en.wikipedia.org/wiki/British_standard_pipe_thread

 

[JohnD]

He's trumped your "old plumber" card, Nige!

 

[Nige F]

Bugger, he sure did .........but "turning" a thread means he was a proper engineer.....not an old craftsman

 

[Agile]

He has probably not used the right term!

I very much doubt that he "turned" a thread on a lathe.

More likely he just used a die stock! Probably a square one 50 years ago!

Tony

 

[Nige F]

not even a ratchet one with 4 dies

 

[croydoncorgi]

Tony - you old cynic!

How do you cut a thread on a FITTING with a diestock?

 

[bripl]

the god of boilers made a mistake never

 

[corgiman]

Praise Be

 

[doitall]

Carbon steel pipe galvanised or not has never been produced for the plumbing industry, in sizes between 3/4" and 1" Bsp.

manufacturers made odd sizes for their fittings, etc, but the pipe end was always the standard Bsp 3/4" - 1" and multiples of 1/4" except 1/8" & 3/8"

 

[chrishutt]

As someone said above, you've probably got a half a brass union fitting left on the ¾" pipe where the lead pipe was connected. I think gas meter unions might use 7/8" thread.

 

[doitall]

As someone said above, you've probably got a half a brass union fitting left on the ¾" pipe where the lead pipe was connected. I think gas meter unions might use 7/8" thread.

Yes Chris and the other end is 3/4" or 22mm. it is so you have to use the correct fittings.

should add some are 1"/28mm with the same nut.

 

[crashanova]

Simple but pure genius - all clear now. Thanks to all.

I've been back to have a good look. The last bit of the lead union, as you all suspected, is indeed still there but the pipework is so blackened with the grime of ages that it looked like part of the iron pipe!! Now it is a piece of cake in theory (3/4 male to 22mm comp) ...

...BUT I can't get the b++ger to shift (that is, the remaining threaded 'coupling nut' of the old lead union still in the end of the steel pipe) despite hours of intensive WD40 and pleantly of measured force.

Final piece of advice from anyone? What's the best tried and tested trick of the trade to get an ancient joint consisting of a brass threaded insert on one side and a female steel pipe on the other (with loads of that old fabricky stuff they used (before PTFE tape came along) clogging everything up as well as plenty of corrosion???) to shift?