re: My New Series Dr Who Tardis Build (image heavy)
The base is pretty big and pretty heavy, and realizing that, I have modified my plans for it a bit.
To start, I'm not going to permanently attach the floor to the base structure. It's not needed because it sits in a pocket made up around the perimeter in a rabbet, and when the posts are plugged into the base, they will overlap the floor in each corner.
I have also removed one axis of the base floor supports as I think it will be plenty stiff without those.
As the boards were about 72" long, after first carefully selecting which edge to cut, I first ran the long 30 degree slopes on each board on the table saw.
The base itself is 60" square and I chose to form the corner joints with large miter joints, each with three #20 biscuits in each. I again carefully selected which end to miter first, considering where to cut to get the best 60" finished piece from the 72" piece.
Because this is a huge miter cut to make accurately, I clamped the board to the saw and ensured it was completely supported and level for each cut when it hung off my table. Even my 12" miter saw didn't completely go through the cut as the motor housing on the right side of the saw hit the top of the board before it complete the cut. I finished the cuts with a handsaw.
The next step was to cut the rabbet on the long edge that would become the notch for the floor to sit in. I used a dado blade in the table saw set to 3/4" width and 11/16" height, which matched the Baltic birch plywood being used for the floor.
The way the biscuit slot cutter works there wasn't a way to set up a fence guide for the three different locations at each miter joint so I used three different spacers under the cutter. Because you lose your ability to align the cutter this way, I tacked guide boards on either side of the housing to guide the cutter. I just put them in there evenly across the miter joint.
And here is the base glued up with Titebond 3 glue and clamped with two cargo straps where I used corner spacers available for smaller band clamps. I used a Baltic birch plywood for the floor because it comes in 60" square sizes and this way I didn't have a joint in the floor what would come from normal 48" wide plywood. The base is just sitting in there as it was an easy way to ensure the perimeter was square. I just tried to pick it up to move it inside and have confirmed it's definitely too heavy for one person with the floor in it.
Next up I'll be adding the base internal supports, which also make the socket for the bases of the posts, and cutting the square holes in the floor for the posts to plug through.