I took a trip to Alan Steel in Redwood City to figure out which steel stock to use. I've been going there since my teens; they've got a great selection, and a ton of random old surplus stuff. When I don't know exactly what I need, sometimes seeing all of the possible options there helps me mentally piece the whole thing together. If you live in the in the SF Bay Area, it's definitely worth a trip, at least once...
However, if you haven't heard, living here is really f'ing expensive. And businesses like Alan Steel must be having a hard time staying in business... this is a clumsy way of saying (defending?) that their prices are really, really high now. I was expecting to throw down about $300 for material (a totally uneducated guess), but once I had everything I needed the tab was to be well over $600. That stung. I had selected 5/8" thick slats, and decided to bring the cost down a little by downsizing to 1/2". I saved a little more by reducing the number of cuts I had them do, but still... Like most DIY projects, I was hoping for a fair balance between saving some money (over just buying a pre-made table) and learning something. it was becoming painfully clear to me that this project was now squarely in the learning experience category.
With my budget blown, I got everything loaded up.
My original design was to have the slats screwed down from above, which seemed like the simplest approach. I thought I'd have enough wall-thickness in my tube stock to tap threads for the screws to bite into:
I went with thinner walled tube, as a part of my cost savings, which ruled out tapping the tube directly. Also, I never really liked the idea of countersinking the screw heads in the slats to keep them flush. I decided to invert the approach; that is, drill "blind" holes into the underside of the slats, tap them, and screw upwards through the bottom of the supporting tube stock:
This approach allowed me to use shorter screws (saving a few $), while keeping the top side of the slats hole-free. Assembly would be a bit trickier, as I'd now need to get things aligned upside-down, and I'd need to drill extra, larger "access" holes in the tube stock.
My design called for 3 supporting trusses, 10 slats, and 2 screws per slat per truss. That's 60 holes to drill and tap in the slats, which was slow going...
More pics coming.