On Jul 8, 2011, at 1:15 PM, Rocket J Squirrel wrote:

> 
> 
> On Fri, 2011-07-08 at 11:44 -0600, Tom Buese wrote:
>> I am w/ Jim on this one, especially if you are not using jack to hold
>> said vanagon off of said squirrel.
> 
> Said squirrel is already known for his squeamishness about climbing
> under cars and has little interest in becoming pressed squirrel. If said
> squirrel were ever to find himself in a situation where climbing under a
> van lifted by a jack were necessary, such as to extract a chest of nuts,
> then said squirrel would chock the wheels and jump up and down on the
> van and push it from side to side first. If the van has not toppled over
> and the jack were not emitting creaking sounds then said squirrel, if
> said squirrel were still a smoker, might then light one up before going
> under in order to take a moment longer to consider the wisdom of the
> plan. Squirrel distrusts large heavy objects on wheels. Now a
> bicycle . . . there's something I'm willing to climb under. 
> 
>> Mr. BZ-is this single shear or double shear?
> 
> Uh  . . . 
> 
Double shear means shearing force directed from 2 opposite directions while single shear would only have the force exerted from one side.

YMMV,

Mr. BZ-Collapse of skybridge in Kansas City Hyatt many years ago killing dozens, cause by shear failure of suspending rods/bolts, IIRC.