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aluminum pier

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#1 orlyandico

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Posted 21 January 2011 - 11:00 PM

hi all,

I'm thinking of DIY'ing a pier to replace the shaky AL-110 tripod of my GP. Hopefully that will stabilize it and get rid of the annoying tendency of the hub to twist about the legs which ruins my polar alignment.

My question is --- will aluminum work for the pier? of course steel will work but it weighs a ton. Will a 4" diameter aluminum schedule 20 pipe (3mm wall thickness -- schedule 40 is quite thick at 6mm wall thickness) be strong enough?

#2 Mary B

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Posted 21 January 2011 - 11:49 PM

My 6 foot tall pier is 8 inch diameter 1/4 inch wall (very close to 6mm) aluminum tube. 4 inches sounds small for the diameter.

#3 Asimov

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Posted 22 January 2011 - 12:02 AM

Should work fine, but I'd be packing it with foundry moulding sand, or maybe crushed granite or maybe even fill it with concrete just to give it some mass.

#4 orlyandico

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Posted 22 January 2011 - 12:20 AM

The reason I want to go for 4" pipe is because that's the diameter of the existing pier end-caps I have, e.g. no need for a pier adapter, I can bolt my GP directly.

I am not going for a permanent pier, but something I can bring to observing sites. So filling it with sand etc. is not an option for me.. I'm only planning to put a rather small scope on it anyway (70mm WO + DSLR + autoguider).

#5 Doug76

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Posted 22 January 2011 - 03:28 AM

It's cheap enough to just try, so go for it. And if it doesn't work out, you'll have a nice tube to do an ATM refractor project some day.






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