On May 19, 7:18*pm, Liz Megerle wrote:
I built a picnic table several years ago. It took a hit from the snow
plow this winter. It's worth repairing, but I can't undo the carriage
bolts. The square part of the bolt head strips the wood when I put a
socket on the nut. *Next weekend I'll try pounding a screwdriver under
the head parallel to the surface of the wood to engage a flat side of
the square. What do you experts do?
Liz

Coincidentally: Just today took two, well rusted such bolts out in
order to reuse a piece of wood.
Couldn't shift the nuts; although one started turning around the whole
bolt.
The nuts, with washers were fortunately not recessed into the wood.
The head ends of the coach bolts were virtually flush with the wood.
Used a hacksaw to cut into the square nuts at an angle I could reach
holding the pieces of wood firmly, until I could split the nuts apart
and beat them off with a small cold chisel and hammer.
If nuts had been recessed would probably have sharpened up a bigger
cold chisel and split the nut with sharp blows of the hammer.
One trick is to have something very firm and heavy below; so the force
of the blows on the cold chisel cutting edge really impacts the nuts
and cuts into them.
Bolt threads are rusty as anything but despite the rough treatment
breaking the nuts off, one of the two bolts, to our surprise, looks
reusable.