On Tue, 29 Oct 2013 00:38:17 +0000, Danny D'Amico wrote:

http://farm8.staticflickr.com/7329/1...e2064872_o.gif
http://farm4.staticflickr.com/3682/1...ccf1e6c8_o.gif

BTW, did you guys notice that the spring, which I oiled a year ago when I
did my other garage door, must have broken violently, since you can see
the spattered oil in those two pictures above, at exactly the point where
the spring broke.

It's interesting that that indicates that the circumferential forces must
have been greatest at the site of the breakage.

Where is DDK_Bob when we need him to make astute engineering sense out of
this observation!