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Date: | Mon, 22 Dec 2008 10:51:40 -0700 |
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ISEN-ASTC-L is a service of the Association of Science-Technology Centers
Incorporated, a worldwide network of science museums and related institutions.
*****************************************************************************
Hey Jeff,
How's it going buddy?
If it were me, I would look at making it a simple as possible; a
hand-held lens, only adding some kind of restraint if it were absolutely
necessary.
(Exhibit Aphorism 6 of spades "Sufficient ruggedisation of loose parts
turns them into weapons" courtesy of Harry White's collection of Exhibit
Aphorisms)
But since you say you 'need' a two axis slider, I might forgo the linear
bearings and use drilled blocks of nylon or Delrin as your bearings.
They would have sufficient slide with enough built in friction. Linear
bearings can be fussy - and expensive. McMaster also has a ton of decent
busings which work surprisingly well, and in a way are much more
suitable for exhibit use (low speed and relatively high off axis and
awkward loads.) Of course, only a little experimentation would answer
all your questions.
Keep it simple, buddy - I'm sure Harry has an aphorism in his deck for
that one, too
Joe R.
www.TheExhibitGuys.com
Jeff Courtman wrote:
> ISEN-ASTC-L is a service of the Association of Science-Technology Centers
> Incorporated, a worldwide network of science museums and related
> institutions.
> *****************************************************************************
>
>
> I need to build a 2 axis slider to move a magnifying lens around a
> large graphic (think of 'where's waldo'). I plan on using linear
> bearings and wanted to know from those of you with experience what
> might be the best way to control the friction in the movement (so an
> over-exuberant 7 year old, like my son) can't wind up and sling it
> from one side to the other.....
>
> Thanks in advance,
>
> Jeff
>
>
>
>
>
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For information about the Association of Science-Technology Centers and the Informal Science Education Network please visit www.astc.org.
Check out the latest case studies and reviews on ExhibitFiles at www.exhibitfiles.org.
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