Craftsman 313 oxygen regulator repair

   / Craftsman 313 oxygen regulator repair #1  

Sodo

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Cascade Mtns of WA state
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I had a cast itron brazing job to do, that was hanging around on my to-do list for almost 9 years.
Not done because my Oxy regulator was not holding the gas pressure setting.
If I set it at 20 psi, it would slowly rise to (whatever, bury the needle ! ) which was not good.
And the flame would change as the oxy / acet mixture changed, always more oxygen.

OK so I searched for a "seat valve" for my Craftsman 313.
I suppose it's a Harris.

I searched for Craftsman regulator parts in a few sittings on a few evenings, probably several hours !
No luck.

And the cast iron stove leg was still broken.
So I decided to ATTEMPT to fix the regulator, so I could get on with my project.

And......regulator fixed in about 45 minutes. :thumbsup:
(mostly fixed)

So heres what was done.
I don't have the slightest idea if it applies to other regulator brands.
Perhaps Harris.

I was careful to avoid getting any oils or any other fuels inside the regulator.

==============================

640907d1581300049-craftsman-313-oxygen-regulator-repair-craftsman_313_seat_repair1-jpg


Here you can see the regulator valve seat.
It has a circular depression.
I assumed that somehow this was the problem, the diaphragm pressure was unable to seal the poppet valve.
I wonder if this was caused by "humming".
Not me humming, the regulator.
I harumph fairly often but don't hum.

640908d1581300049-craftsman-313-oxygen-regulator-repair-craftsman_313_seat_repair2-jpg


I put 220 grit on my orbital vibrating sander.
Held it as "parallel as possible".
That black stuff I thiught was a real hard rubber, but it's not.
It resembles "pencil lead"

640909d1581300049-craftsman-313-oxygen-regulator-repair-craftsman_313_seat_repair3-jpg


Rigged up an arrangment to spin the brass part of the seat.
I cut a little disc of 360 and 600 grot wetordry paper.
Had a little neoprene chunk to press the paper atainst the seat
while spinning it with a 19mm socket.

640910d1581300049-craftsman-313-oxygen-regulator-repair-craftsman_313_seat_repair4-jpg


Here are the two reconditioned seats.

640916d1581301058-craftsman-313-oxygen-regulator-repair-craftsman_313_seat_repair5-jpg


It still leaks just a little, the needle climbs 5 psi in 15 minutes when not being used.

Anyway it worked well enough to braze my cast iron stove leg.
The oxy gas pressure doesn't climbwhile it's being used, only when you close the mixer valve out at the mixer handle.
For now I just gotta remember to ALWAYS turn off the oxy valve, or it's liable to pop a hose or something.

I wonder if sanding the seat with 600 on the vibratory sander would ___really___ fix it.
I'll fix it later.
Probably.
If it doesn't fix itself.

It could bed in....
 

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   / Craftsman 313 oxygen regulator repair #2  
Things like that you want to use water soluble fine grit valve grinding compound and lap them in by polishing them together. Just like lapping engine valves. Use a little bluing compound to check your fit. You want 100% contact across the surfaces. I have done lot of lapping jobs of all kinds in my vast career. Used to a lot of industrial machinery overhaul, compressors valves and etc. Its not hard just tedious sometimes. We always had several grades of lapping compound, fine silicon oxide paper, crocus cloth, jewelers rouge, and a lapping block for flat surfaces. Compressors with reed or ring valves and their companion valve plates were a common job. We even did hand fitting of babbitt bearings with scrapers and bluing to check the contact. Nobody wants to pay for that kind of labor cost today. By the 70s it was machine shop work or replacement with new. We only did disassemble and reassemble on stationary stuff. That was really nice and fun work. We did a 2 cylinder 24" X 24" ammonia compressor once. Every part had to handled with a chain fall. That is all a lost art now.

Ron
 
   / Craftsman 313 oxygen regulator repair
  • Thread Starter
#3  
I met an old guy last summer who was still scraping babbitt on big ship bearings.
Ready to retire though.

I thought about lapping it somehow or another but there was just no way to align the two surfaces.
The spring pushes the surfaces together.
And the black stuff seems soft, like pencil lead.
There's plenty of material away from the sealing area to poke at (to see if it's soft), but i didn't.

I just thought maybe it'll seat itself, and since it was so easy to put it together and try it, I did.
And then it seemed good enough to braze with, so I did.
And then I finished my brazing project.
Then found out that the poppet valve leaks slowly, but that's where I'm at.
If it doesn't bed in I can smooth it with 600 grit and it HAS to be better.
 
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   / Craftsman 313 oxygen regulator repair #4  
The part is what Harris calls their encapsulated seat. It's the same seat they use on all of their industrial regulators. When I worked for Lincoln Electric/Harris I watched tiny little robots built the seats in Georgia. They work good until they don't but I like the idea.
 
   / Craftsman 313 oxygen regulator repair #5  
The part is what Harris calls their encapsulated seat. It's the same seat they use on all of their industrial regulators. When I worked for Lincoln Electric/Harris I watched tiny little robots built the seats in Georgia. They work good until they don't but I like the idea.

Yeah,
My dad had one just like it that went bad. His neighbor, a lady, worked for them in N. GA. She saw them and took them to work and brought them back fixed. Said they were warrantied forever. N.C.
 
 
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