What size are they?

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hoppercar
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What size are they?

Post by hoppercar »

I have a pair of superscale okadee blow down valves..I'm wanting to make a wash down fitting and hose, to wash down the engine at the end of the day that screws into the blowdowns...I've been told there 3/8-40......5/16-40......and 5/16 model taper pipe.....nothing seems to fit ?....I gave an old superscale catalog that says 5/16 - 40 model taper pipe, I found and ordered one from godshalls.....nope, doesnt fit ???????
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makinsmoke
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Re: What size are they?

Post by makinsmoke »

I thought the MTP sizes were, 1/8-56, 5/32-48, 3/16-40, 1/4-40, and 5/16-32, which the latter equates to 1/16 NPT.

3/8-40 sounds strange.

Surely Barry would have used “industry standard” threads...
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makinsmoke
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Re: What size are they?

Post by makinsmoke »

Sorry, 5/16-27 MTP equates to 1/16-27 NPT.

I found a post by Dave Bortz mentioning the 3/8-40 thread.

There’s a chart of common used threads in Nelson’s book. The only 40 thread per inch fittings I see are 1/8-40 straight threads, 3/16-40 MTP and 1/4-40 MTP.

Maybe Dave can provide some clarification. He owns Superscale now. Might give him a shout.
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makinsmoke
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Re: What size are they?

Post by makinsmoke »

I have a question. I’ve heard of and seen others do what you are suggesting.

Is it problematical to wash down your engine with boilet scale and rust and stuff coming out of your boiler? Or do we assume if we take very good care of our boilers the blowdown flow is free of solids?

Maybe needs to be on another thread.
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Dick_Morris
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Re: What size are they?

Post by Dick_Morris »

Haven't some MTP pipe fittings been made at 40 tpi instead of 32 tpi because the thread was so course?

Also, be careful of 32 and 40 tpi straight thread, both common on UK fittings. Although the same tpi, the thread form is different, My recollection is that the UK threads are 55 degree rounded crest and root versus 60 degree sharp V U.S. special.
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Bill Shields
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Re: What size are they?

Post by Bill Shields »

I have all of the above. 27, 32 and 40 pitch with and without taper.

This is why -> when I build pumps for people I ask specifically which thread they want in what service.

Maked no difference to be when building...and customer needs to match existing pipe fittings.
Too many things going on to bother listing them.
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cbrew
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Re: What size are they?

Post by cbrew »

makinsmoke wrote: Mon Jun 14, 2021 11:09 pm I have a question. I’ve heard of and seen others do what you are suggesting.

Is it problematical to wash down your engine with boilet scale and rust and stuff coming out of your boiler? Or do we assume if we take very good care of our boilers the blowdown flow is free of solids?

Maybe needs to be on another thread.
I have been washing my running gear down this way for better part of 15 years.
scale and rust is never and issue unless you miss treat that boiler.
the only time i take pause is if i had been running at a train with hard water. I will wait and clean when the boiler water is fresh, aka the morning of the last run day.
one think i also do right after the wash, i blow everything down with compressed air and oil and grease around.
If it is not live steam. its not worth it.
hoppercar
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Re: What size are they?

Post by hoppercar »

Yeah, I saw that post from Dave bortz...saying there 3/8-40.....no way, that's way to big....my old superscale catalog, said it's a special model taper pipe....5/16-40......instead of the standard 5/16-27 m.t.p. I found Godshalls has a 5/16-40. Mtp...tap and die.....that didn't work either......I'm beginning to think I got the odd ball , black sheep okadee valves, which is kinda weird, knowing how Barry was a stickler for accuracy ??
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NP317
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Re: What size are they?

Post by NP317 »

Both my steamers have been standardized to use Hanson high pressure quick-fit mini fittings.
This includes a steam-cleaning lance that connects to the blowdown outlets. (not shown in the pics below.)
I threaded the blowdown valve outlets to match the Hanson fittings: 1/8 - 27 NPT. They have worked for 16 years with no problems.

The mufflers (from lawn mower engines) on the blow down outlet direct the output away from neighboring steamers, and decrease the ear-hurt.
These are a Kitsap Live Steamers requirements in the steaming bays, with a welcome result.
Pics to illustrate.
RussN
Attachments
317 Blowdown fitting.jpg
317 blowdown tools.jpg
317 blowdown.jpg
317 Steam Blowdown.jpg
hoppercar
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Re: What size are they?

Post by hoppercar »

Well, after some head scratching.....I found out they are 5/16-40 model taper pipe.....why Barry didn't use the standard 5/16-27 standard model taper pipe....beats me
amadlinger
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Re: What size are they?

Post by amadlinger »

Hi Hoppercar,

Excerpted from SuperScale Catalog No 9, which I believe was the last that Barry himself published:
Capture.JPG
and specifically regarding the Okadee blowdowns:
Capture2.JPG
Sincerely,
Adam
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