The spring after we moved to this property I was clearing some brush and came across this pile of parts that had been a park bench. The wood was well rotted, but the cast iron appeared to have been powder coated and wasn't badly rusted. Whatever the finish, it was still mostly intact. I hosed the mud and crap off of the parts and set them out to dry, then stashed them in my barn for further attention - someday.
Fast forward 5 years - it's either do something with the parts or throw them out. I chose do something. This is what I had to work with - 4 pieces of cast iron that were in really good shape plus three 48" long slats and a little mystery piece of wood. The purpose of cast iron and the long pieces of wood were obvious, but the the little piece of wood went - ?? But a least now I knew how long the seat pieces should be. As it turns out an extra half inch would have made the project a lot easier.
My son is a fine furniture builder and a few years ago he "outgrew" this basic planer and gave it to me. I used it to plane down the flooring to the thickness I needed for the bench project. There was some oak flooring in the attic of my barn, left over from when the house was built. The wood was crap, with splits, knots, and of course I had to rip off the tongues and groves. It was nominally 6" but with machining off the tongues and groves and the kerf from ripping it down it came out to the exact width of the original seat slats - 2 3/4". I mapped out a way to get seven 48" pieces of 3/4" wood out of the 6 eight foot long scraps.
After cutting the slats to thickness and cutting them to length I ran them through my router with a round over bit to - well, "round over" the edges. I finished the wood by brushing on four coats of clear gloss spar varnish.
At first I thought about stainless steel carriage bolts, then flat head bolts, then oval head bolts. In the end I chose these cool internal hex stainless steel 1/4 - 20 round head bolts to hold it all together.