Fastening Question

[John Grenier]

We are nearly finished with two name boards for the USCGC Biscayne Bay. They are 12"x52"x1.5" Mahogany carved like a traditional ribon or scroll with gilded letters and varnished. Replacing some plain routered boards that are through bolted to each side of the bridge on about 3/16" steel sheet. I would like to conceal the fasteners, so mounting from the back is a must. So here is the problem this is an ice breaking cutter, ship rams up on the ice and the weight of the ship breaks through or it simply crunches its way along. Our little carved signs will take quite a bit of vibration. Of course the fasteners need to be stainless steel. I thought about epoxy some sort of modified nut in a recess in the back but havn't done anything yet.

All suggestions are welcome.

Thanks
John

[Danny Baronian]

The strongest option would be to drill a through hole through the panel, countersink the face, insert a carriage bolt and affix to the board with a nut on the back, leaving a stud hanging out the back to fasten to the ship, fill the front countersunk hole - assuming it was painted. Otherwise .....

Next best method would be to use a hanger bolt - half wood thread, half machine screw. Pre drill the wood for the bolt and insert into the wood, the machine threads are then coming out of the back as a stud to be mounted to the ship. Don't over tighten, and use both flat and lock washers for final assembly. For the conditions you describe, I'd use a minimum of 4 - 6 bolts to attach per sign. A threaded metal insert could be applied to the back of the signs, and install a stud into those, but I believe the hanger bolt would hold better.

It would be wise to use fiber stand offs on each bolt. You don't want water trapped behind the sign.