Fluid Power Design Problem - Working with Steel Tube

You don't mention what the wall thickness is of the tube you plan to use but what about something like this: http://www.harborfreight.com/large-tail-pipe-expander-37354.html

There are other types and sizes available.

Use Google and search "exhaust pipe expander tool"

Or

If it is steel tube similar to RGS (Rigid Galvanized Steel) conduit what about threading the tube, installing a coupling and then brazing?

Another term: Swaging.

I've looked for swaging tools for the brazing of hydraulic tube (wall thickness in the .065 range, with an OD of 0.5") but so far everything I have found involves the swaging of a crimp ring or ferrule onto the tube, not the expansion of the tube for insertion of "next section".

Chris

You are probably looking for flaring tools.

I have been in the Hydraulic busines for 30 years. Worked on old machines from the 40's up to the newest stuff. The only "brazed" fittings I have come across were for use with face o'ring type tube ends. These were silver brazed.

As for swaging a good hydraulic hose shop may have hose crimping machines suitable to swage your tube..... but it just isn't done. Flare for upto given wall thicknes, and external crimp type fittings (Parker BU works for me) for heavy wall tube.

If it is stainless steel, why not use a Swagelok or Parker coupling? These will probably last as long as the tube. Alternatively the tobes can be butt-welded using orbital welding.

If it is something like copper, then (thinking out loud) you might try getting some larger size tubing with inside diameter matchibg your tubes outside diameter and cut off suitable lengths to make "brazing" couplings.