Originally Posted by
jeff-oh
I am assuming the 25mm has a wall thickness of 1.6mm (ID ~22.4) for a 2mm radial clearance. That will make a nice fitting join with little play and would only need 12.5 to 15 cm of overlap (min) could go deeper but may not be necessary. But play around with the fit to make sure to lessen any side to side play.
Here's a thought. Purchase
25mm :Qty 1
22mm: Qty 3
Cut 25mm into 1/4 = 93.75 cm: Yield 4
Cut 22mm into 1/3 = 125 cm: Yield 9
Assemble 22 - 25 - 22. Gives 4 poles with total length of just over 3m using a 20cm over lap. Could also cut the 22mm to 107cm and have a 13cm joint. This would make the poles closer in overall length dis- assembled. Or cut all at 93.75 cm for an assembled pole length of 2.56m w/ 12.5cm overlap. This would only require 1x25mm and 2x22mm or 3 poles total.
Also I'd suggest not using the pin lock. Run a bolt or use steel rivets to make a stop. This has 2 advantages. 1: it allows the torsional relief at the assembly joint. 2: it allows quick assembly and disassembly without messing with fasteners. (structure is under compression so it ill not come apart in use). Also allows for pinning/bolting the Vertexes for ease of building and disassembled pole management.
Engineering wise, the 3 section design is better as it allows for the poles to be shorter for storage and transport, and it moves the joint (the weak point) away from the highest stressed area (the middle) for an overall stronger design.
I am assuming the 25mm has a wall thickness of 1.6mm (ID ~22.4) for a 2mm radial clearance. That will make a nice fitting join with little play and would only need 12.5 to 15 cm of overlap (min). But play around with the fit to make sure to lessen any side to side play.
Without doing the calculations I looks that this would have be capable of holding 150kg with margin.
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