Jim--Good idea. Thanks for bringing it up.
It was always fun to watch a young mechanical engineer's eyes light up when
shown this trick. One of us old timers would spring this at the peak of the
kid's enthusiasm about going and doing an elaborate computer analysis on an
existing mechanical structure. This is a trick they didn't teach in
engineering school. I guess the profs figured it was hard enough to teach
strength of materials and all the math it involved without the students
knowing about an easier way.
Here's some thoughts from my own experience:
Fish scales usually range to 50 lbs. 100 lb and up are hard to find.
Old spring style bathroom scales work well as long as they are laying
reasonably flat.
Spring type baby scales go up to around 25 lbs. Getting a little hard to
find at flea markets. Really handy to have around the shop.
Sherline makes a 2000 lb hydraulic crane scale (pull only) retails around
$250 but sometimes can be found on ebay for 1/4-1/3 of that.
Sherline also makes similar trailer hitch scales (push only) that go up to I
think 1000 lb and sell for a lot less.
Engineers refer to sophisticated and very accurate spring scales as "Force
Gauges" Often quite cheap on ebay. Usually have 10-32 male threaded
connections instead of hooks. Larger sizes in the 50 lb plus range are
1/4-20 or 5/16-18 male threads. Most will read either pulling or pushing by
setting a lever.
Chinese made 1" travel dial indicators are usually priced under $20 and are
pretty good considering what you pay.
Ed Weldon
----- Original Message -----
From: "Jim Dincau" <jdincau@qnet.com>
To: "land Speed List" <land-speed@autox.team.net>
Sent: Saturday, October 28, 2006 12:20 PM
Subject: Doug, dont go to any trouble about the anti roll bar
> Doug,
> A responder on the land speed list solved my problem. All I have to
do
> is put a spring scale on the roll cage and measure the force required to
> roll the car. Using that, a little trig and the manufacturers chart of bar
> length vs arm length stiffness ratings I should be able to calculate the
> required moment. Don't get involved in resurrecting old computer programs,
> it can take up our whole day and ruin it.
> Jim
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