Re: telescope

On Sat, 12 Jan 2008 11:43:44 -0800, John Larkin wrote:
On Sat, 12 Jan 2008 17:10:27 GMT, Rich Grise <rich@xxxxxxxxxxx> wrote:
On Fri, 11 Jan 2008 20:11:27 -0800, John Larkin wrote:
On Sat, 12 Jan 2008 01:41:03 GMT, Rich Grise <rich@xxxxxxxxxxx> wrote:
On Fri, 11 Jan 2008 16:14:24 -0800, John Larkin wrote:

http://www.lmtgtm.org/images.html

My client is bidding on one of these:
http://mysite.verizon.net/richgrise/images/Dish-Frame-Partial.gif

And I get to design the tooling fixtures that will hold the sticks
in place while we build the trusses. I haven't drawn in the
circumferential struts yet; I envision them shipping the hub
and 16 trusses and a whole pile of struts to the site, and bolting
it together the way the carnies do a roller coaster. :-)

It's not electronics, except for the signals it reflects to the
feed horn; I honestly don't know if it's for satellite comm or
a radio telescope, a la the VLA. I'm sure that as soon as we get
the PO, I'll find out. :-)

How big?

42' 4" diameter. We can only fit one truss at a time in our shop.

The hub is about 3' in diameter, so each truss is a little over
20 feet long; and if oriented orthogonally, over 10' tall. Of
course, we'll design our fixture so that it's kind of tilted,
both for balance and to save space, albeit that makes it closer
to 25' long and about 7' or 8' high.

Say, John, you're a gazillionaire - if you need any precision
fab done, we're only an email away!

I'll keep that in mind, but we avoid serious machining, because it's
too expensive. We prefer punched/folded *** metal and laser-cut
plastic stuff.

We just decided to do a new line of small-box (7x5x2.25 inches)
products and looked over the usual suppliers of enclosures... Hammond,
Bud, Buckeye, Rose, like that. Everything was too expensive or not
quite right mechanically, or had grounding/thermal problems, so we
designed our own. Turns out you can generally have a ***-metal shop
run off a batch of custom enclosures cheaper than you can buy+modify
the standard stuff.

I'll post some pics of our design. A bunch of people had good ideas,
so it's cheap, very versatile, and should look good.

Buckeye does have one interesting process. They nc machine flat pieces
of plastic and then heat-bend them into very clever interlocking
snap-together shapes, with all the device and mounting holes,
standoffs, and lettering done at once. They can even do copperclad
plastic for intenal shielding.


Shades of Vac-u-form! ;-)
http://www.samstoybox.com/toys/Vac-U-Form.html

Cheers!
Rich


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