On Jul 13, 7:12*pm, Tim Wescott wrote:
On 07/13/2011 03:30 PM, wrote:





On Jul 13, 4:04 pm, Ignoramus23641ignoramus23...@NOSPAM.
23641.invalid *wrote:
Would it be safe to work under a jacked vehicle, if I use a mechanical
jack like this:

https://picasaweb.google.com/lh/phot...UboR9xO3bjAhN7....

i

The old advice is correct, NEVER work under a vehicle supported just
by a jack. *Seals fail on hydraulics, mechaincal ones can twist or
tip. * HF has jackstands so cheap, it's foolish not to have a pair or
two. *I've personally had a car roll on me supported just by a jack, I
rolled out just before it came down or I would have been squished.
Jack it up, stick the jackstand under it and set it down on that.
Either that or get some heavy duty ramps. *Have a set of those, too.
If you're working on the rear and want to jack that up, block the
fronts with wheel chocks. *All this stuff costs peanuts compared with
what COULD happen if the thing rolls while you're under there.

Even if all your relatives have to pay for is a cheap funeral, that's
still more expensive.

And if it squishes you and leaves you brain-damaged but alive and needy
-- that's _way_ more expensive than jack stands.

Always use jack stands, and think about what's under them (the driveway
at my old place featured concrete that was only 1/2" thick in places --
I learned this one day when I stuck a jack under a car and jacked the
driveway down an inch or two. *After that, jack stands always went onto
pads of thick plywood or sections of 2x12).

--

Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details athttp://www.wescottdesign.com/actfes/actfes.html- Hide quoted text -

- Show quoted text -

Another very good point.

I have had several jacks fall through the driveway/garage floors over
the years.

Driveways have hollow spots under the pavement where trees rot out and
animals dig.

Garage floors can be just as devious.

The wider the base the jack/stand sits on, the safer it is.

And ALWAYS have at least one backup support in place before you put
yourself in harm's way.

TMT