Those are carriage bolts. Grinding the top off to make them flat will release whatever they are holding.
We need a little more info. How thick is the plywood they pass through?
Can you find the Nut on the other end of the carriage bolts?
If you find the nuts, what size are they?
__________________
'04 Newmar MADP, 1100w of solar, Rubicon toad
|