Re: ATM Center of gravity of semicircular elevation bearings

["Albert Highe" <ahighe@ix.netcom.com>]

There is an easy way to measure the center of gravity of semicircular
elevation bearings (or any other object), with or without cutouts. Support
the bearings from a first location and draw a vertical line from the support
point. A plumb bob will help do this. Then support the bearings from a
second, different location and repeat. If the bearings have a mirror plane
of symmetry along the thickness, only two support points are necessary. If
the object is irregular, three unique support points and lines are necessary
to find the COG. Of course, repeating with more points will increase the
accuracy slightly.

Albert

----- Original Message -----
From: Tom & Lou Krajci <krajcit@3lefties.com>
To: <scope-drive@egroups.com>; <atm@shore.net>
Sent: Sunday, August 13, 2000 1:12 PM
Subject: ATM Center of gravity of semicircular elevation bearings


>
> I've recently been doing some math to figure out the location of the
center
> of gravity of semicircular elevation bearings (assuming the are solid, no
> cutouts, etc.).  Since my integral calculus is not what it used to be, I
> approximated the solution in a spreadsheet, slicing up the bearing's shape
> into 100 narrow strips to approximate the circle.
>
> I ended up with this answer:  the C/G is located at approximately 42.5% of
> the radius.  Does this sound about right?
>
> This piece of info is helpful to those wanting to precisely balance their
> design of a motorized big dob that moves on sheet metal and roller
bearings.
> (If you move on teflon and formica you can ignore this extra math/analysis
> in your balance calculations.)
>
> Tom Krajci
>
>