Here's an edge scenario, but for us "shade tree mechanics" worth considering.
A couple years ago I was working on my starter in the garage and had just put the front end up on jack stands. I turned away for a second and heard/felt a kinda crunch-kerchunk! noise. Out of the corner of my eye I saw the truck drop about an inch.
The jack stand under the front left side was about 12" from the corner of one of the concrete slabs that comprise the floor of my garage. The slab cracked and settled under the jack stand due to a void that had formed under the concrete.
It could have easily bounced the truck off the stand. If I'd been under it when it happened I probably would have had a heart attack.
When one of my neighbors tore out his garage floor recently to pour new concrete he discovered 6"+ void spaces under the concrete.
Lots of these new suburban houses are put up quick, and the soil isn't compacted/settled adequately. So, worth extra precautions and careful placement of the Jack stand (not near a slab corner). I use ramps whenever I can in my garage. If the wheels are staying on, I use ramps.
eep:
