Chris I blame you for all these altars that are being built today and now you thinks we over thinks ’em–huh. You whipped the masses into a frenzy— now Woodworkers are trying to out pretty each other–out wood species each other –out Rube Goldberg each other. I made 2 benches in 30 years neither had a through dovetail but many were made on them and I have no idea but I would bet a dollar that neither weighed 280 pounds but they both had tons of wood on them. If you want the bench as a destination god bless but it was intended as a mean. Thats my rant I could be wrong
We cut the supports 16 in. long, but you can place the second shelf at whatever height you like. Screw the end supports to the walls at each end. Use drywall anchors if you can’t hit a stud. Then mark the position of the middle supports onto the top and bottom shelves with a square and drill 5/32-in. clearance holes through the shelves. Drive 1-5/8-in. screws through the shelf into the supports. You can apply this same concept to garage storage. See how to build double-decker garage storage shelves here.
There are simple jigs like a trammel baseplate and T-square, but you’ll also find a vacuum-clamping jig you can use to rout surfaces without clamps getting in the way, a dowel-making fixture, and router jigs to help you make fluted columns and even flamed finials. Bill also included several variations of router tables, including an ultimate table I built for my own shop.

I clamped the top to the side of the base, as I had done before, so that the edge with the knot would be easy to work with. I mixed up some ordinary five-minute epoxy and added just a touch of black epoxy pigment. I applied this freely. After about twenty minutes I checked on it and found that in the deepest spot the void wasn't entirely filled, so I mixed up another batch and added more. After that had cured for a bit I eased the top to the floor and applied a coat of oil to the bottom side. I planned on attaching the base to the top the next day, and I wanted the bottom side oiled to keep it from absorbing moisture.

These sorts of things are usually glued and screwed, but it's actually the glue that holds them together - the screws just hold everything tight while the glue cures. Screwing into hardboard or 1/4" ply is an exercise in futility, so I just used glue, and used my two 4x4's as long clamps. It would have been a bit easier, if I'd done this before I'd rough-cut the 4x4's, but it worked out.
Grizzly is a company currently undergoing an upheaval. This brand was once known as a manufacturer of professional grade tools and equipment for woodworking products. Though, in recent years, that reputation has begun to slip a bit since being bought by the Chinese company SIEG. These days, whether the Grizzly product stands up to its previous standards of excellence often has more to do with what you are buying than the company itself.