The Home Machinist!

is not a question of pressure, but one of an air leak (or water)...will probably be OK if you are not sucking with an injector

be aware that the axial pressure to compress an o-ring and make / hold a good seal is probably going to be a bit more than you expect and might require more then finger torque to hold.

you can think about making the union with a pilot (nose) (like the Hansen fittings so that the o-ring is captive...but use a knurled ring to tighten rather than the pull-snap ball widget. this way you don't have to worry (so much) about getting it REALLY TIGHT...once the pilot is into the o-ring, yo...

failure is from dropping the o-ring on the ground and not having a spare. properly done, o-rings work just fine...but ALWAYS have a few spares on hand. Even the o-rings in Joe Tansky's fittings (Joe doesn't make them)...occasionally 'get cut' and leak air and can cause problems as a result. I always...

carry lots of extra 0-rings with you

.5625 A/F

another option are paint ball gun quick disconnects...stainless steel, no valving...low cost...good for very high pressure

The fittings come from Hansen originally...get them from Joe

viton o-rings will be just fine there....

looks very pro-fessional.

be prepared for slight leaks along the center -pipe until it gets hot.

Jack:

if you are getting some tread plate etching done and are open to adding to the order, I would be interested in some. Although my project is 1", the 3/4" scale tread patter will be just fine for my 'one of a kind' modelling.

short people is the reason God made lumber and nails.

I have a work platform around my Bridgeport Series II machine. Even though I am 6' 1", I find it a very tall machine, so a 6" platform all the way around makes life easier for me.

that is basically where I was headed...it's a variation on the old British steam fitting. BvB just scaled them up.

Stay away from compression 'olives' here....the copper under them will compress and they will eventually leak.