I have made many a work bench, I use steel 1/4 x 2 angle iron frame with three 1/4 x 2 angle cross ribs. I used 2 inch tubing as legs with a pedestal. The legs are welded with the cross rids 18 inches from the ends, and 2x4 boards bolted to them. I have a back splash 1/4 x 2 angle standing up to the 8 ft height. I have a shelf 14 inches, up about to the 6 ft level and the top shelf, it is about 18 inches.
I have 1/4 x 2 flat bar up the side supporting the shelves, on an angle. The Right side I have a piece of 1/4 inch plate cut, with 1 ft sides, in a 45 degree angle welded to the base angle Iron I use 2 x 6 fir planks they are wedged in and bolted. the right front corner has anouther plate to support the vise bolted in tight then welded.
I have the vise positioned so the inner jaw is flat with the edge. I have 3 x 3 tubing welded in inside of the cross brace that way when I have a long piece I slide a 3 x 3 board out and support it. I am going to add one more tube in the middle.
I have a self 1 ft from the floor the bench top is at the 33 inch level. I have peg board on the back splash and boards on the shelves.
I am a mechanic most of the steel, I got as trades for doing work.
The steel is painted with white Tremclad three coats, before adding the wood the top is 1/4 inch press board. The bench is 4 ft x 8 ft x 8
I made three of them, with shelves, one just flat. It takes some time But it is permanent.