Large Plug With Non-Standard Thread

Could it be a BSP tapered thread?

Does it look like this?Home

RVZ717--I don't know what BSP tapered is, so I'll look that one up and see. Looked it up. NO. 4" BSPT is 4.45" diameter and mine is 4.25". BSPT is 11/inch and mine is 16/inch. BSPT is 1:16 taper and mine is closer to 1:50. Thanks for the suggestion anyway.

Lyn--It looks like the brass part of your picture. (But is cast iron--probably brass wouldn't have the physical strength to survive potential point loads.)

Thanks for your quick responses, friends. --JMM

If unable to locate exact replacement, then maybe a PolyEthylen or similar plastic bung could be made slightly undersize and "self thread" into the mating metalic part.

I suspect though that teh previous response has your answer.

Just...

More likely they would have to send the sample to a machine shop to custom fabricate more. This is a "poke-thru" opening in a floor potentially subject to heavy traffic including vehicles and similar. Fortunately, it is NOT in an adjoining area subject to being sat on by passenger jet airplane wheels!

--JMM

I remember in the '60s we sent a "wheel" spanner (wrench for big valves on a steam ship) to a Hong Kong shop to make more of the same.

They made us a bunch of them, exactly as ordered, accurate even down to the hammer marks from heavy usage of the original one we sent in as a pattern......

Are any letters or numbers visible on the plug or the mating part?

Hi, Tornado,

No markings on the threaded plug. The insert in the floor is the inside of a female threaded fitting cast flush with the floor surface in the concrete. Not much hope--sorry. I have already traded emails with the manufacturer of electrical power receptacles for installation in concrete floors of airplane hangars and terminal aprons--he doesn't recognize it either.

--JMM

Sounds like a job for cnc!

jmueller these probably are flush cleanout plugs. They are a plumbing pipe fitting which have male pipe threads which are tapered. They fit inside a "fitting cleanout adapter". These plugs ailable in cast iron, brass, & plastics PVC and ABS. Available at hardware and plumbing supply houses. The one you have is a 4" size about 4-5/16" od.

Roadapple,

We have been there and tried that. Plumbing and electrical share the same thread specifications--11 per inch (we are 16), 1" per foot taper (we are no more than 3/16" per foot and that much is in doubt), and are 4-3/8" pitch diameter (we are 4-1/4").

I wish it were as easy as your answer proposed. Thanks--Jmueller