Calling All MadModder Thread Experts! Help Needed!

[Symon]

So, if you're viewing...your're and expect. Thank god...cause I need ya helps!

I need to identify this fine thread that's on a brass elbow that I need to find another of. Most of the oil pipes on my 1950s machine use this fine thread.

The male end of the elbow is 1/4" BSP (20 tpi)...I believe.  The female end is, err, well, I think, maybe, possibly...1/2" BSB (British Standard Brass) as it has about 26 tpi

I don't have imperial thread gauges atm (busy buying other stuff and lost my old ones) so measured the BSP male, subtracted .25", counted the threads (20 tpi) and got 1/4" BSP. Already sort of knew this and confirmed with a known fitting. I was just wondering if it was BSW as they were close.

ANYWHO...the female thread had stumped everyone I asked, stumped Crosslings, and stumped Cromwells

But I came across BSB and realised it's very likely this. BSB doesn't subtract any 0.25" to get its named size and the dimensions and tpi seem to match 1/2" BSB.

So have I cracked it? And where the hell can I find an elbow that's male 1/4" BSP to female 1/2" BSB?

Maybe one of you smart guys will go "Hey, just buy x and it'll be the same fit" , tell me I'm wrong, or point me in the directing of maybe someone who deals in old brass fittings

Here's a pic. I have another elbow that has both ends female mystery fine thread, but it has to go into a 1/4" BSP either way.

[naffsharpe (Nathan)]

I'll hazard a guess at either a Wade compression x 1/4" bsp elbow or a 1/4"bsp x Gas compression elbow. Both the same in practical terms and should be available through your local hydraulic hose specialist.
Nathan.

[seadog]

I think you're correct in assuming it's BSB. It would be 1/2" BSB. Where you'll get fittings from I haven't a clue. They are not a standard item as far as I am aware.

[Pete.]

That looks like the oil pipe fittings on my old J&S surface grinder except mine are smaller I think. I will go and measure them on the weekend and if they are the same you can have them.

[awemawson]

Both British Standard Brass and British Standard Cycle threads have a 1/2" X 26 tpi thread in their range.

Tracy Tools carry taps and dies for both

[seadog]

Note that BSB has a standard Whitworth angle of 55° whereas CEI is 60°.

[philf]

Symon,

They're standard compression elbows still made by Norgren.

See: http://www.accltd.com/images/pdf/Norgren%20Metric%20Compression%20fitting%20en_9.6.002.pdf for metric tube sizes or http://www.accltd.com/images/pdf/Norgren%20Inch%20Compression%20fittings.pdf for imperial.

On page 5 of each it gives you the thread size.

I assume the part you think is 1/2" BSB has a hole in it to take a tube - what size is it? I may have one lying around.

Cheers.

Phil.

[Symon]

Thanks guys! So nice to ask a question and not be met with snobbery. Just good old help

awemawson: As seadog mentions...BSC's a different angle. But I had found Tracy Tools and making this thing is a last resort. Sounds anti-mod but for the moment I'm on the hunt for a replacement so I can crack on and finish the machine

philf: I'll read through that

Yeh, the fitting is for an oil line. It's 5/16 pipe and a wee olive. I bought some new pipe and olives to re-plumb the inside of the machine better. But I had to steel an elbow from one place to achieve the inside. Need to crack on with it so thought it ok as the extra elbow will be on the outside. 

If you had one lying around I'd literally pass out!

All of you...MASSIVE thanks for your input

[Pete.]

Symon,

I just popped out and checked and mine are for 3/16" pipe, so too small for you, sorry.

Pete.

[Symon]

Oh well. Thanks very much for trying Are the treads and diameter the same?

I can't find any BSB in that pdf you linked to. But I should be able to find a 1/4" bsp that I can get to use 5/16 on pretty easily. Guess the female doesn't care if it's BSB or not. The male has to be 1/4" BSP but as long as the female accepts 5/16...it doesn't matter.

Even 1/4" BSP to 8mm ID will do. Would just smart, a bit, to throw metric on this imperial beast

Would still like to be sure I identified the piece correctly. Might buy a little bit of 1/2" BSB threaded tube off eBay just to check.

[philf]

Hi Symon,

Sorry, I checked and haven't got an 8mm or 5/16" elbow - only 6mm x 1/8" BSP.

I could cobble something together with 4 fittings but it looks very ugly.

We had many thousands of similar compression fittings where I worked but I daren't go back on a visit to raid their stock.

There is one on eBay but £6 and looks to be just the elbow without the nut or olive! A 1/4BSP to 8mm push in elbow is much cheaper but generally have some plastic in them if that would present a problem.

Phil.

[Symon]

Bought a 1/4" BSP to 8mm last night. Under £4. It's ugly but it'll go in the inside and the one I put there can come back to its original exterior place

I'll sort a tap out for the BSB thread for future issues.

Thanks so much for your help

[David Jupp]

....
The male end of the elbow is 1/4" BSP (20 tpi)...I believe.

 

FYI - 1/4" BSP is actually 19tpi not 20.

[Symon]

Yeh, that's why it's "approx.". There was only 0.25" to measure and that'll always be a wee bit wishy washy.

But it fits a known BSP fitting.

[hanermo]

I´m glad it´s sorted, but if it was me...
I would have tapped it with the nearest metric tap I had to hand.

If its loose, add goop.

Unless one is making a concourse-level original car, or its a 200 bar through spindle coolant part (that would not use a rare thread), etc..

For low pressure, just eyeball it and use teflon tape or goop as appropriate.
Thinks I..