Mystery thread....

[foy9999]

I am trying to replicate the corroded metal fuel pipes on my 1974 Daimler Double Six VDP.

This return pipe (from engine under passenger side of car back to boot) has a join under the rear seat.

It is a nice robust neat design comprising a brass(?) male threaded fitting brazed/soldered to the front pipe and a female threaded nut held on the rear pipe by an olive.

Despite checking lots of data re threads I can't find a match for this.

The thread diamter is 1/2". It has 24TPI and lastly the spanner size is 5/16W (the distance across flats for this is 19/32 I reckon)

5/16 Whitworth is the only spanner that fits

5/16W spanner is wider than 9/16th but less than 5/8. probably 19/32

nut unscrewed reveals olive

24TPI

 

[shenion]

Looks like a standard 5/16 compression fitting.

Nut should be 0.53", thread is 1/2x24.

Edit: the nut size may be different, I have seen cases where they are different. The thread size looks right.

 

[Windy Miller]

19/32 is about 15mm. Could it be a metric thread?

 

[Robotstar5]

The thread chaser doesn't appear to line up in the picture, have you got a pitch gauge?

 

[foy9999]

Robotstar5 Yeah. I have a thread gauge at home but in the garage that was the best I could lay my hands on last night. It's definitley 24TPI tho.

Windy I considered that because my metric thread file seemed to fit (24TPI being pretty close to M1.00) but the 15mm spanner was too tight.

shenion That makes sense. I was just puzzled as to why it didn't appear on any of the thread charts. Does this mean the 'compression fitting' thread was a stand alone thing. ie not BA/Whitworth/UNC/UNF or anything?

Also when would these 'plumbing' fittings have gone to the 15mm & 2mm equivalents we now have?

 

[nickk]

thats quite fine ,sounds like a pipe thread.

 

[chunkolini]

This reminds me why the metric system makes so much sense.
How many units of measurement were used above?

 

[MattF]

1/4" BSP perhaps?

 

[Tino]

Just a thought, you could reuse the fittings. Heat them and remove from the old pipes solder to the new pipes a new olive, and you don't need to figure out what the thread is.

 

[foy9999]

Bit late with this reply Tino but I eventually did un-solder the fitting but to this day never managed to find another one like it.

A lot of ppl on the car forum said it is an Enots thread (1/2" x 24TPI). The spanner that fits it is 5/16 Whitworth

I did find a solution by buying female compression nuts for each pipe to connect to a double male union.

I've never even found a fitting the same regardless of the thread. I suppose you'd call it a solder-on male straight connector

on left we have workaround using readily-available (BSP?) fittings. on RHS is original

original fitting (solder-on straight male connector?) melted a bit when de-soldered using oxy-acetylene.

 

[foy9999]

Well better late than never as they say. I've just worked out what I need and they are available. Only difference is the thread is BSP (19 TPI) instead of Enots (24 TPI).

It's a male iron. Never heard of them before but am sure if I'd put my question on the plumbing section I'd have got an answer.

They come in all different sizes but I'm going with 8mm x 1/4. The 8mm refers to the tube-side and is modern equivalent of 5/16" pipe and the 1/4" BSP thread is approx 1/2" diameter like the original was.

Maybe if I'd posted the query on plumbing section I'd have got an answer years ago but hey you live and learn

this is called an iron connector apparently and is just what I need

 

[Kayos]

Male iron to copper was my first thought, but I am a plumber...

 

[foy9999]

Just looking at the forum this is in - The Brew Room. I'm pretty sure I didn't put it in there at the start.

Quite annoying when threads get moved by someone who assumes you didn't take the time choose an appropriate forum.

I wouldn't have dreamed of putting it in the plumbing section tbh. I'm guessing I'd have put it in the Projects section (automotive, bikes and trailers) but it was over 5 years ago so hard to say

 

[Stueeee]

Haven't used a 1/4" BSP "Iron" fitting, but all the others have a tapered BSP thread, not what you'd want if you need to screw on a parallel style nut.

BTW, I have come across another equally irritating non-standard fitting when I was working on an old Bentley fuel system. Those fittings turned out to have a 26 TPI "Brass" thread.

 

[cumbriasteve]

Just looking at the forum this is in - The Brew Room. I'm pretty sure I didn't put it in there at the start.

Quite annoying when threads get moved by someone who assumes you didn't take the time choose an appropriate forum.

The thread is where you put it, there has been no moderation of the thread since you started it so the only person to be annoyed at is yourself

 

[slim_boy_fat]

The thread is where you put it, there has been no moderation of the thread since you started it so the only person to be annoyed at is yourself

View attachment 128178

Seven years IS a long time to remember things.......

 

[foy9999]

I'm not convinced lol. I've never hear of The Brew Room. Thought that's where ppl went in to talk about TV shows and stuff

 

[foy9999]

Haven't used a 1/4" BSP "Iron" fitting, but all the others have a tapered BSP thread, not what you'd want if you need to screw on a parallel style nut.

BTW, I have come across another equally irritating non-standard fitting when I was working on an old Bentley fuel system. Those fittings turned out to have a 26 TPI "Brass" thread.

Aargh. Now I'm worried about the taper but thanks for the reply Stueeee.

That's interesting about the Bentley. The Daimler/Jaguar XJ model's fuel-tank fittings took Whitworth spanners right up to the 80s which was a bit of a surprise to me but the thread on this fitting made things even more complicated

 

[foy9999]

The thread is where you put it, there has been no moderation of the thread since you started it so the only person to be annoyed at is yourself

View attachment 128178

The Brew Room strikes again.... I know for sure I didn't put this one in there (see post #12) Can you show me otherwise?

http://www.mig-welding.co.uk/forum/threads/wet-tile-cutter-blades-25mm-or-25-4mm.64413/#post-828655

 

[cumbriasteve]

The Brew Room strikes again.... I know for sure I didn't put this one in there (see post #12) Can you show me otherwise?

http://www.mig-welding.co.uk/forum/threads/wet-tile-cutter-blades-25mm-or-25-4mm.64413/#post-828655

It did not strike 'again', by using that term means the first one where you stated

'Quite annoying when threads get moved by someone who assumes you didn't take the time choose an appropriate forum.'

was actually moved when in fact it was not and allowed that statement to come back and bite you in the rear somewhat .

The blades thread was moved, probably because the moderator considered the brew room which is a very active section would give you a faster result for the information you sought, there would have been a timed redirection and notification of the move in your alerts at the time.