is aluminum strong enough for a pier?

Wanna make a scope? Or better still, grind a mirror yourself. Or, you have some good tips in making a really useful accessory? This is the place to show what your hands can do...
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orly_andico
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is aluminum strong enough for a pier?

Post by orly_andico »

I'm thinking of making a full pier for my two mounts. This will eliminate the need for a half-pier, and also eliminate my problems with hub flexure on the tripod due to differential load.

I know that steel pipe would work well for this application, but steel pipe is quite heavy. My Orion SVP 16" pier (which is 4" diameter steel pipe, schedule 40) is eye-poppingly heavy, I am never going to make a pier out of schedule 40 pipe, I'd get a hernia lifting it.

So... I'm thinking of using schedule 20 aluminum pipe. This is 3mm wall thickness. Would that be strong enough? I know the Losmandy tripod uses aluminum... failing that, it's back to steel. Maybe schedule 10 (2mm wall) is enough. Cheaper too and easier to cut/drill since I don't have power tools.



That said.. where can I buy steel pipe? Aluminum pipe I know where to get, in King George Avenue (the place there sells it in up to 6" diameter).
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cloud_cover
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Post by cloud_cover »

Hmm.... consider a limited fabrication run for interested parties in Singastro? A pier will be far better than a tripod!
I wonder: If you shorten the pier height, won't it be lighter then? Also less flexure.
Another thought: You can fill a non-ferrous pier with water which will make it tremendously heavy BUT with in input hole on top and a release valve (or stop plug) below, it can be light for transport when needed.
Just my 2c
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orly_andico
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Post by orly_andico »

yeah kevin.. if you notice the usual tripod + half-pier + EQ head tends to sag a bit even with moderate loads, unless you have a strong spreader.

i don't have the metal-working skills (or tools) to do a fabrication run, but if i can get a good design, i may have it fabricated back in Manila. a friend there owns a metal-fabrication business. I'm thinking short enough that with the typical scope (SCT) you can view at zenith while sitting down.
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Post by cloud_cover »

Sounds good. Shipping though.... these things are heavy.
I imagine if you can get it sturdy and priced at about a hundred or so there'll be a lot of interest. After all, the AP Pier is only a metal tube with 4 hinged legs held by tension lines to adjust to tilt and costs well over USD500 :)
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orly_andico
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Post by orly_andico »

check out the pier-tech piers for a whopping price comparison!

you are right i'd love for the price to be $100.... it's what i'm willing to pay, myself. The downside is... I don't think it's possible to make the pier to a good quality standard, for anything close to $100. Note that the Vixen half-pier alone is $200+ (SGD) although that does include the top and bottom caps. And Vixen has economies of scale..
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Post by cloud_cover »

Part of me wonders why the half-pier costs so much. It is, after all, a metal tube with machined fittings on top and below for attachment.
I'm thinking: If piping isn't expensive; hinged legs don't need to be precise (Precision will come with operator adjustment of tension wires) and a flat-top welded on with central hole and fork arm (Eliminating need for precision drilled hole) much like my surveyor's tripod, then surely it can be cheap and simple to manufacture? just a thought :)
Pier tech piers are wired (electronics) and height adjustable (which must be precise or else levelling and alignment are lost) so definitely much more expensive than an analog model :)
Last edited by cloud_cover on Sat Jan 22, 2011 11:15 pm, edited 1 time in total.
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andeelym
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Post by andeelym »

I am also interested in making a aluminum pier much like the Tech2000 Quick Draw Pier (http://www.tech2000astronomy.com/giro/).

Its using aircraft aluminum, but I'm not sure the exact specs. If you are going to get someone to fabricate, count me in!
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