I'm not an engineer but believe compressive strength is higher than shear strength. Things are generally engineered with a high safety factor, maybe 6X the limit given. I don't know how this product was designed but would trust good engineer to design it.
I've worked in fibers, plastics and composites R&D and frequently see poorly designed materials. I prefer to buy products that have been in the market for many years and tested by time.
It's a "repair" manual. If bodywork is being done and components replaced, it is VITAL to know where every spot weld is, so they can all be drilled /cut out, and the repair welds done in all the specified locations, following the specified repair procedures. This is to ensure a "crash-worthy" repair.
If not "better" they are at the very least "more consistent" - particularly in location.
And as long as the weld strength excedes the shear strength of the pins, it is NOT an issue. Generally (proper)welds are as strong or stronger than the base metal.
You can have 3 wheels "on the ground" and still have the jack stand carrying half the weight of the car -
A pair of 2000 lb stands can support 2000 lbs, not 4000. Stands are solad AS A PAIR and the rating is FOR THE PAIR.. So, ONE stand is good for 1000 lbs, not 2000 - and the curb weight of a K-Car is a minimum of 2300 lbs. - so if ONE stand is supporting one side of the front of the K-Car, it will be shifting the weight of the car to the opposite rear wheel - taking load off both the opposite front and the same-side rear wheel - so the stand is taking a load SUBSTANTIALLY over 1000 lbs.
If 2 stands are used under one side of a car, the car transfers weight to the opposite side, and the 2 stands combined are holdinf substantially UNDER half the weight of the car. If the 2 stands are used under the front of the car, depending where the stands are located they can either transfer load to the rear wheels or take load off the rear wheels - so the stands can be taking close to half the weight of the car, or substantially more. 2 to jack stands are "light duty" stands. Knowing how to use them properly is required to be safe.
This doesn't take into account the folly of using them on irregular or soft surfaces, which can put over 30% more load on each of 3 legs contacting the floor if one is not contacting the floor.
i use 4 of these:
When I use Jack stands I put another big piece of I beam or similar wood under there too as a safety.
DerbyDad03 posted for all of us...
Welds and design look good to me.
You wouldn't catch me under a car supported by those contraptions. I use, and will continue to use solid blocks of wood. And to your point, why bother with them when there are other safer options.
rbowman wrote in news: snipped-for-privacy@mid.individual.net:
I disagree. It looks to me like the strength of the contraption depends on the shear strength of the curved tubes and the sheet metal stampings they fit into. Heavy gauge sheet metal stampings, to be sure, but they're still sheet metal stampings. And I don't trust their shear strength.
No way in the world am I crawling under a car supported only by these things.
DerbyDad03 wrote in news:4ea8a746-f3cf-4534-badb- snipped-for-privacy@googlegroups.com:
You don't worry that the shear strength might not be up to spec? If it's made in Communist China, I sure would -- I've encountered plenty of "Grade 8" ChiComm bolts that were no harder than a US-made Grade 2.
I didn't say "I don't need to worry", I said "I don't need to *wonder*" because "wonder" was what rbowman was "surprised" about.
Which way is the grain oriented? Using a piece of log, upright the way it grows, is NOT a safe stand for most applications. Building a pilon of stacked 4x4 "logs" is - but it's clumsy
I'm not convinced any other jack stand design is any safer
Looks like plate steel and tubing to me.
I don't know. My cuts and bruises heal by themselves but autobody work is expensive!
Just kidding.
My 50 Olds had both an X frame and a box frame around the X. One time at work I thought I would drive over a pile of dirt, so I gave it a running start and only made it part way. When I got out of the car, all four wheels were off the ground. Fortunately one of the 10 of us was driving a little crane. He put me back on the ground and the car was totally unhurt. And I guess the foreman didn't find out because I didn't get fired.
(the dirt pile was about 4 feet tall.)
Thanks, Clare, and thanks everyone.
I don't know what Derby does, but those guys who break a board with a karate chop have the board oriented 90^ from the way it looks. People are used to the grain running parallel to the long side of a board, which makes it hard to break a board, but when they do it, the grain is parallel to the short side. People look at the wood and think otherwise, so the guy looks amazingly powerful. I find this all sort of annoying.
The old cars were built like tanks, no doubt about that. There were almost as lethal too.
I'm not quite why I'm mentioned here. I never said anything about wood or grain patterns or karate chops. You may have me confused with someone else.
He has you cofused with someone with thicker skin, it appears.
Yah, if you don't know the proper way to orient a block of wood, you'd better put your tools away and call a pro before you hurt yourself.
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