Frame to Floor to Walls

[Cliffmeister2000]

Thanks fellas, for the additional clarification. I appreciate your thoughts, as I continue to work out all the preliminary design design in my [too] little head!

Try paper. It's easier to erase.

[Aguyfromohio]

Well, we are getting to this stage in our build and made our choice of how to attach walls and floor to the frame.
We used a method that will function pretty well, but we can't really recommend -way too much trouble.

Our frames are custom welded square tube, 2 x 2 tube, 14 gauge ( 0.070 wall thickness). A few pieces of angle right down the center between the cross members.
The walls rest on top of side rails, floor rests on cross members.

We decided we liked 1/4 inch lag screws up from the bottom into walls and floor, but worried we might crush our lighter weight tubes if we went clear through.
So we drilled 1/4 inch holes clear through, then opened up the bottom hole to one inch to allow the lag screw head to pass through, and allow a socket wrench to drive the screws.

It took 2 men all of a very long day to drill all those holes in two such frames, especially when using that Uni-bit to enlarge the bottom holes.
I don't think I will ever get all those sharp steel chips out of my garage. And of course now each frame has twenty or thirty 1 inch holes on the bottom as perfect entries for wasps and bees to settle into a steel tube nesting paradise.

Funny how doing things the hard way improves your vision.
Now I see why the approaches posted above mostly have either a wooden cleat screwed down first, or have angle iron mounting tabs.
Next time we will use one of those two methods to make things easier.
What we did should work like a charm, and a $9 bag of plastic snap-in plugs from McMaster Carr will close all those 1-inch holes.
But next time we will use a different approach, one that has wooden cleats or steel angle tabs.