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Thanks Ewen!
They do have a very suitable 57.15mm (2.5 inches) with a strange 5.38 wall thickness but I can't find exactly where they stock it most likely WA. They do have a flat $90 freight rate but I can't afford a full 6.5 metre length and I'm going to call tomorrow and ask if I could buy it by the meter, the $90 flat freight will still be a hard hit but they are the only place with it.
I can bore it out to 50.8 ID for camera adapter (2") one end and still have 3mm wall thickness or thereabouts and the other end machine down approximately to 51 (50.8) OD and still have 3mm wall thickness.
It's ideal but not local. I highly doubt I'd ever use a full length but I may ask an engineer friend locally if he'd have use of it and maybe offset the price going halves (I really don't need that much either but it would get used for something eventually).
Failing that I can buy the 60mm OD x5 tube locally in a 1 metre length for a reasonable price and a 50mm OD x3 cheap, slide the 50mm up the guts of the 60 a few inches and machine one end down to 50.8 leaving a very thin 60mm section wall (.4mm but reinforced with the 50x3 and bonded up the guts. With the locking screws in place I don't see any real issues with doing it that way. The other end I can bore to 50.8. That of course depends on the accuracy of listed sizes, not always exact but I could get lucky. It's a 50 minute drive each way and I may go to Bathurst tomorrow to have a look, I don't know yet,
The 57 with 5mm wall would still be my best option, I'm going to talk to someone from Capral on the phone tomorrow.
My engineer friend recommended 60mm solid bar but I'm throwing away too much material (if only I had a trepanning tool ) and its far from cheap in 6061 t5. If/when I decide to have a go at my own quality focuser I'll buy the 60mm solid but that won't be for a while at this stage.
Or just pay the dollars to get a mix and match set online but I'd rather do my own. Then I just have to learn the anodising process all over (I did it for a living in the early 80s but they had all of the chemicals and equipment, I just provided the man power).
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