Quoted from pinmister:Looks like a great idea but I would not risk bending female threaded hole or just the sheer value alone that bolts need to hold. 300-350 lb. machine being carried by zinc bolts? Cool idea-but not for me. I just use a good pair of gloves. My .02
http://www.almabolt.com/pages/catalog/bolts/proofloadtensile.htm
They are stronger than you might think.
Even a 3/8" eye-bolt is rated for 1,200 lbs (and that's with a 5 to 1 safety ratio).