[TowerTalk] Aluminium telescopic mast

[Grant Saviers]

"Customary" size tubing is usually 0.065" thick wall and is ID-OD line 
to line so won't telescope with 0.125" diameter steps. (also it often 
isn't 6061 T6/T651 needed for yagis). Telescoping tubing has 0.058" wall 
so with its larger ID, telescopes nicely (don't ding the ends though). 
DXengineering is a great source, but unfortunately doesn't sell (I've 
tried to change that) longer than 6' lengths except for some boom sizes.

Onlinemetals.com is now stocking most diameters of 0.058" wall (and 
0.120" wall) and will sell full lengths for pickup (Maybe also via 
freight, but I'm close to a warehouse, so don't know) and 8' for UPS 
delivery.  Now and then I've found 0.058 wall a in a few diameters in 
full lengths at other metal distributors but paid dearly for that 
"opportunity."

So if you are designing/modeling inch sized tubing antennas, best to 
stay within the  6/8' length constraints.  Sometimes that is hard to do 
for sections that also internally sleeve another section.

Grant KZ1W

On 7/17/2019 7:49 AM, M??ximo EA1DDO_HK1H wrote:
> Hi all,
> 
> Telescopic Aluminum masts are easy to make using metric tubes.
> Using 2mm wall tubes, then 30, 35, 40, 45, 50, 55, 60, 65mm (and so on) external diameters you get the telescopic feature easily, leaving 1mm clearance between tubes.
> 
> I was trying to do same with "american tubes" but I couldn't find any size to get same telescopic thing.
> 
> Anyone knows how to make a telescopic aluminium mast using customary tubes?
> 
> Thank you
> 
> 73, Maximo
> 
> 
> 
> <http://foro.ea1ddo.es/>
> 
> 
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