I taught a class and lab in engineering mechanics years ago (smash
lab). We tested (broke) specimens in tension, compression, torsion,
fatigue, etc according to the standardized test procedures. The
students learned about elasticity, buckling, yield strength, etc. For
fun one time I bought some of those cheap muffler pipe jack stands
and had the students test them in a press that was good for 120,000
pounds. The main idea was to check the manufactures rating which I
believe was 6,000 lb. Memory is hazy here, but I remember the jacks
were good for 6,000 lbs and beyond. When they began to fail, they did
not fail catastrophically. They began to crumple and gave plenty of
warning that something was wrong but were still holding the load.
Disclaimer. This was just one jack out all the jacks in the world. I
suspect that how the jack is positioned and used is more important.
ie; that the load is placed correctly on the jack and that the jack
is on a solid base. I guess this is like buying helmets. If you
aren't protecting anything valuable, buy a cheap one. If your head is
valuable, buy a good one.
Tim Collins
1966 AH Sprite
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