Cinder blocks? They are useless. And if you happen to get a block that was made with a dry batch that day, it'll be brittle and fracture, and I would not want to be under something held up by that kind of block or any kind of block.
yup, exact same pin sheared on one of the larger jack stands at work. when i saw that all it was is a shear pin that takes the weight, that is stupid killer design. i used those stands faithfully under various equipment and heavy trucks- wow i could have been killed.
the style with 3 holes and a pin are a little better.... the screw type are best. nothing wrong with wood blocking either.
HEY! FYI to all. Nobody mentioned that there is an active recall on these jack stands. They will take them back in whatever condition, refund your money, or replace with new ones. BTW, I never get under a vehicle without jack stands, but I always try to have a floor jack or secondary support device under there. Just in case of a slip.