View Single Post
  #48  
Old 04-06-2011, 10:14 PM
tomscat1 tomscat1 is offline
Registered User
 
Join Date: Feb 2011
Posts: 182
Quote:
Originally Posted by funola View Post
I dug out my Craftsman ratcheting jack stand and gave it a close look and a quick test. Mine is the 3 ton and I assume the 4 ton is of simillar design. I raised it halfway, crouched, stood and balanced myself on it, reached down and yanked upward on the handle. To my surprise, it (and I) dropped all the way to the bottom! That was very sobering! Jack stand with pins will never do that! I was expecting it to catch on the next tooth on the rack but not so. The handle only needs to be raised upwards 3/4" to release the rack for it to drop. I'll try to find the owners manual and see what warnings/ instructions are provided.

With the car's weight (let's say 3000 lbs) on the jackstands, how much force is required to hit the handle at such an angle and cause it to go up 3/4"? Any mechanical engineers here want to take a stab at it? The jack release handle is 4.5" long.


Very interesting post.... Thank you very much. I would like to post your results in other forums to continue to raise consciousness on the subject of safety... As well as productive discussion. Yours is a most interesting experiment, worth looking at some more, in my opinion.
__________________
[SIGPIC]
Tom
SE Connecticut
1975 W115 300D

visit my blog:
http://mercedesdieselrebuildingdiederich.blogspot.com/
Reply With Quote