Thanks for the replies folks ... bit more progress ...
[1] That transfer tube thing ... which requires two banjos fixing at right angles ... and in the correct place ..
One idea was to soft solder them on in situ ... but all I have is the electronics 60/40 stuff ... serious doubts about that. Another alternative is tinmans solder ( comsol ??? ) which has a higher melting point but it's not cheap and I have no other use for it AFAIK.
Then I found out about JB Weld Steel Reinforced Epoxy. This appears to be OK up to 315oC.
Having got some I tried it out. Bit of 1/4" brass round, tickled with steel wool to clean it, poked a a 1/4" hole in the end a bit of 5/8" x 3/8" steel flat and epoxied the two together. Just pushed in and rotated a bit. Left it for two days ..
Scrounged Norm's Infra Red thermometer, [ nice, must get one, new toys always welcome ] applied propane torch, thermometer said about 430oC , well, it did come apart with a good heave via a 10" adjustable, but I would guess about 40 ft/lbs.
Remarkable product, not cheap, but then neither is solder ...
I doubt if that tube will get anywhere near 300 odd C in free air.
So, the tube is now epoxied together.
Good enough for me, chief. We're in business...
Made two gaskets from .25mm PTFE sheet, as per Bogs' write up elsewhere in MM..
Cut out with an OLFA Compass Cutter and the screw holes done with Maun hole punch pliers.
I do have some small wad punches, but they made a hideous mess, so got a new tool ... [ toy ]
[2] The displacer guide bush leaked like a sieve .. should know by now steel bar is undersize, and reamers cut oversize ...
So that has been remade, this time the 5/16" shaft hole has been bored out to suit the actual 0.309" which passes for 5/16" rod ..
A lot better, couldn't have been much worse actually ...
Tried the warm it up and see bit, when the displacer is pushed in and out there is quite some push and suck on the power piston rod ...
Maybe the Gods are smiling on their humble servant ???
BC