What is the difference between A and B torch fittings?

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B Fittings        A Fittings

What is the difference between A and B torch fittings?
TC, Seattle

The Tinman Respondeth:

"All US torch fittings are the standard"A" and "B" type fittings which connect the torch to the hose and the hose to the regulators.

In the photo you see hoses at the bottom, adapter fittings in the middle and torch bases at the top.

The hose fittings on the left are large and are "B" fittings.
The black hoses on the right are "A" fittings.

These are the US standard fittings for oxy-fuel connections.

Fuel is left hand thread, and the nuts have hash marks across the corners to identify them.

Oxygen fittings are right-hand thread and have no marks on the nuts.

If you have a hose with "B"fittings (shown)and need to adapt them to a torch with "A" fittings (shown), then a simple adapter is available at welding supply houses or through us to make the connection (shown). The same goes for "B" fittings on a torch which needs to adapt to a hose with "A" fittings (Not recommended because of fuel supply issues with smaller fittings).

Adapters are available to join hoses to each other Male-Male "A" or Male-Male "B" fittings, sold in pairs, Oxy and Fuel. Male-Female fittingsare shown in the photo.

All of the hose, regulator and torch fittings are standard in this country, Oxy and Fuel, "A" and "B". If you have a weird fitting, then it is probably something from across the water somewhere. I know the Meco is sold in Arabia, so things can get moved to unexpected places. I took my Meco to Italy, and it did not fit the metric system there. Neither does it fit in the Netherlands or OZ. (Australia).

Folks abroad can silver braze fittings together to make their own adapters, and if their work is good, it looks like the factory joints I see on ourus-style Oxy-Fuel adapters all the time. Be safe, observe carefully, and have fun doing your work.----Kent"