The frames of my wooden benches are bolted together using 10 mm galvanized coach bolts, the tops are made of 40 mm x 200 mm pine, the legs 100 mm sq, NZ Oregon, this is much less dense than North American Oregon, our trees grow too quick, a 50 year old tree is ready to fell for timber, where as in its native America, the same size tree would be at least 200 year old. while the bench is solid, it really needs a harder surface toi work on, on top. The cost of a wood framed verses a metal frame was very similar 30 years ago, but I had all the bolts needed, and a saw mill a mile away, so wood it was.
Ian S C