Picked up the tubing on Thursday and was able to start making the boom for my rig today with help from my Dad.
Here's a quick summary that he made up -
1 Aluminium Round Tube (6082T6) 11/2 in x 14 swg - 5000 mm
(38.1 x 2.032 mm) @ £14.17 + vat
1 Aluminium Round Tube (6063T6) 15/8 in x 16 swg - 5000 mm
(41.275 x 1.626 mm) @ £12.49 +vat
38mm Hydraulic pipe clamps £3.70 each plus £1.96 p&p
From Parquip of Somerset on ebay
42mm anti vibration pipe fixing clamp £1.20 each plus £1.40 p&p
Shaft locking pins, 8mm diameter steel £1.95 for 5. postage included with clamps above.
Twin cup heavy duty aluminium clamps. £19.98 each plus £$.00 p&p
Jawel Paints from ebay
We bought two 5M lengths because it gave better options. We cut both into 1.25M sections.
The smaller diameter should technically just slide into the larger. In reality it doesn't, it needs a little sanding, no big deal and it ensures a nice tight fit. We used 20cm joining sections, 10cm fixed and 10cm sliding. The sections were split lenghtways with a thin grinding disc, with the 'sliding' section opened up with a file, this gives a little spring to the joining section which makes it easier to get apart again. The 'sliding' end was polished, as was inner of the female 'receiving' end of the tube. The fixed end was epoxied in place with JB Weld. (we'll also centrepunch the outer tube in several places once we find the centrepunch. Though since we had to use a rubber impact hammer to fit them, they're unlikely just to work loose.) An 8mm hole was drilled through the joined tubes for the fixing pins. We use different end spacings for the pins, so the tubes can only be fitted together one way. The two open ends will be filled with plastic caps when we get round to it. The tubes will be engraved with numbers, so we know at a glance which goes where and their orientation. Tube 2 will have a tower for a tensioning cable, still to make that up, as well as the fixing rings for near the ends of tubes 1 and 4 for the cable to attach to.
The anti vib. pipe clips have nuts tacked on for both 8mm and 10mm threads. We'll likely reinforce the welds, more out of paranoia than anything else. Though we really like the hydraulic pipe clamps, we may end up getting 42mm hydraulic clamps.
We're thinking of using Hydraulic pipe clamps on the arms of the ali suction cups. To those we'll weld 10mm nuts, then use 10mm stainless threaded rod, and turnbuckles if necessary, to achieve a huge range of adjustment at very reasonable cost.
The larger diameter tube boom will be used initially, we'll also make up a slightly shorter one from the smaller diameter tube. Whichever works best Scott'll keep and sell off the other one on ebay, won't pay for the whole project, but likely to at least cover the cost of tubes and clamps.
And for some photos -