As requested, here is my basic plan for the workbench base. This was my first (semi) successful drawing with Google SketchUp, so please pardon the crudeness. I plan on starting on this phase in the next week or two (after payday).
The wood will be southern yellow pine dimension lumber. With the exception of the 2x6 lower stretchers, the rest will be 2x4's. The upper stretchers will be single thickness, the outside legs and feet will be glue-lams of 2 studs, and the center legs and foot will be three studs thick. The reason for the additional thickness in the center is to allow for deeper mortises for the opposing tenons. The front-to-back stretchers are offset for the same reason.
The reason for using feet instead of straight legs is to alleviate the need for front-to-back stretchers at the bottom. This lets me place my 2x6's lower, giving more room for the later addition of tool storage cabinets between the legs. It's not shown in the drawing, but each foot will have a slight relief cutaway in the center, leaving a pad at each end to help compensate for any unevenness in the floor or later warpage.
All joints will be 1" thick pegged mortise-and-tenon, with as much length and width as possible. The upper stretchers will be low enough to clear the hardware for the front vise, but still give as much cabinet space as possible. The top will have 1" holes that fit over 3/4" pegs in the top of each leg. This should keep the top in place and still allow for wood movement during climactic changes.
Overall height, including the benchtop, will be 38" (hey, I'm 6'4").
I'm wondering if I should raise the 2x6 stretchers up some for more racking resistance, or if they'll be fine where they are. I want room for cabinets, but not at the expense of strength. The present distance between upper and lower stretchers is now 22".
Any thoughts, questions, or suggestions will be greatly appreciated
-- Robert - Visit my woodworking blog: http://littlegoodpieces.wordpress.com