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Vintage stand pipe threads

920 views 15 replies 7 participants last post by  29stude 
#1 · (Edited)
Ok this is slightly off topic...but I know there is a wide variety of knowledgeable people on here.

A number of years ago I was given a collection of old Fire hydrant standpipe parts. I've finally got round to doing something with them (a short standard/reading lamp is the plan).

However I've discovered that not all the threaded parts fit together properly.

There is a blank cap which screws onto stand pipe perfectly, but the 2 instantaneous couplings only screw on about 1 1/2 turns before locking up. All the threads are clean and undamaged and none appear to be tapered. I assume the 2 couplings, originally came frome a different stand pipe, with slightly different threads.

Basically I'd like to fit all them all together, so that the couplings screw all way onto standpipe. I'm hoping that someone will be able to identify the threads on either standpipe or couplings, so I can then look out for a suitable tap or die as required.

7G whitworth thread gauge seems to match up reasonably well. I have tried internet search, but possibly due to the era these were made, there are a variety of threads shown, none which seem to match.

thanks, Gav

1. standpipe with one of the couplings screwed on as far as it will go..(1 1/2 turns)



2.Blank cap which is attached to stand pipe and fits perfectly.



3.coupling which I belive originally had a washer inside, so would have had to screw fully onto a standpipe to make a seal.

Automotive tire Fluid Gas Drinkware Composite material


4. pitch of standpipe.



Automotive tire Automotive lighting Motor vehicle Audio equipment Auto part
 
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#12 ·
Hadn't thought of them, only 5 mins away as well cheers:tup:

a friend involved in a very old steam roller pointed out all nuts bolts and threaded holes were numbered as threads were not standardised when it was built so each pair of threads were matched to each other maybe you have this type of problem?
drseg: I did consider they might be unique, but believe FS stand pipes had some degree of standardisation in this era.

A long shot, but perhaps a trip to the local fire station. They may be able to see if the threads are still used on current equipment, and they may give you a contact at whoever supplies their hoses.
Already tried that route Neil, Unfortunately modern Fire service stuff is different.
 
#9 ·
used to be involved in engineering and company were making hub nuts for Rubery Owen artic trailers pressed with 600 tonne press bored then threade4d with a cri dan threading machine li8ke a lathe but had a thread cutting tool which moved at a set rate inside the nut, not like a tap which touches all of the inside of the nut just one side of the inside of the nut, these nuts had a bore of about 4". if not done and set up correctly the thread could be too tight or loose on the hub, we used go or no go testing tools to check they were within tolerance at the machining stage and after heat treatment.

a friend involved in a very old steam roller pointed out all nuts bolts and threaded holes were numbered as threads were not standardised when it was built so each pair of threads were matched to each other maybe you have this type of problem?
 
#11 ·
if it's just going to be a light stand why not 'grind' all but 1 1/2 turns of thread of of either the stand pipe or nut so they push together all but the 1 1/2 turns they currently do then screw on the rest of the thread? for what you need that'd work well.
neil.
 
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