What's the best screw for this bench restoration project?

[ilyaz]

Hello Everyone,

I am restoring a cast-iron-and-wood garden bench similar to https://secure.img1-fg.wfcdn.com/im.../5109/51098490/Sundberg+Wooden+Park+Bench.jpg. Need to attach a heavy cast iron back piece to two horizontal wooden slats that are 1" thick that are "layered cakes" of oak and other types of mostly hardwoods. The iron piece has 4 holes for screws on each side (4 on top, 4 on bottom) that are 1/8" in diameter. Not only is the iron piece heavy, the back of the bench is also reclined putting extra stress on the screws and the wood. Is there any particular type of wood screw that would be best for attaching the iron to the wood?

Thx

 

[Johnboy555]

You could do this a couple ways. I would probably go with a larger screw, either brass or stainless, #10 or #12 X 1" long. Brass is not as strong, but stainless will stay shiny (aesthetics). You may have to drill the holes in the metal a bit larger , but that's easy. Another hint, put a drop or two of exterior glue in each hole, it helps keep the screws from loosing.
Sorry , after looking at the picture I see that the wood is only 3/4" thick, so you would need 3/4" screws.

 

[slownsteady]

Is the cast iron piece resting on a ledge in the wood?

 

[ilyaz]

Is the cast iron piece resting on a ledge in the wood?

Sort of. Not really. That's because the back is reclined, not vertical, and the iron piece is attached form the back, not from the front. So it sort of rests on the bottom plank.

I bought some decking screws and planning to drill pilot holes in the wood. Tried without pilot holes on a test piece and it cracked, which was to be expected I guess. With the pilot holes no cracking, and I drilled a few extra holes in the iron piece so will have 7 screws on each side -- hopefully that'll be enough