Moving right along with the benchwork for St. George, I ripped material for 1×3 joists from scrap I had around. Since this area is going to have a solid plywood top I wanted the joists to be a consistent height — in this case, 2-1/2″. I measured the joist lengths from the track plan spaced at 16″ intervals. They are mounted according to plan but can be easily repositioned if needs dictate. I predrilled #6 countersink holes from the bottom of the girder flanges and screwed the joist to the flange from the bottom with 1-1/4″ drywall screws.
Next, I ripped a some 3/4″ square and marked it out as cleats for fastening the plywood top. Mine are 4″ long. I predrilled them as required on the drill press and fastened them to the joists with 1-1/4″ drywall screws. Another screw will come up from the bottom into the plywood to secure it to the benchwork.
Working from underneath is a tenet of L-Girder benchwork. If I ever need to rearrange joists for a switch motor or any other reason, all of the screws are accessible from below, not buried under track or scenery.
Next will come the 3/4″ plywood top cut to the rough contour of the plan and fastened to the cleats. Homasote roadbed is on order from Cascade Rail Supply but I don’t expect it for a few weeks. That will give me plenty of time to transfer the track plan to the plywood surface and size things up.