Hack for Spreading U-bolts

Sometimes a U-bolt is just a bit too narrow for the job. I can usually manage spreading a 1/4" diameter U-bolt by hands/fingers but wonder what knuckle joint stress I may pay for later.
Today I realized a hack for this task when I needed to open up several 5/16" diameter U-bolts & couldn't do it by hand strength. If a vise with a step between jaws and frame is available, install nuts on the U-bolt thread ends (to protect the threads) & use the steps on the vise to push the U-bolt open a fraction by opening the vise jaws.

Attachment 46010 Attachment 46008 Attachment 46009 Attachment 46011
Why didn't I think of this years ago??

Very good idea. Those type of bolts aren't always very precise and sometimes need a little adjustment.
It may have been done but not mentioned, but it would be prudent to keep a firm grip on the bolt while spreading it this way. The rounded edges of the nuts may cause it to slip off the jaws and send the bolt flying.

Your vice idea is a good one if the vice jaws stick up enough to grip the nuts safely. The easiest way I've found to spread U bolts up to an inch in diameter is to use a couple lengths of pipe over the bolts. Obviously the bigger the bolt the bigger and longer the pipes need to be.

With my luck, the nuts would slip off the vice and the whole thing would smack me in the face.
Now you know why I wear a mask...