OK,
Down and Dirty, Solid construction, Super Cheap, Minimal tools/skills
make a simple doweled box joint.
do this by drilling a pilot hole in the sides, just big enough for the screws to pass. drill thrm 3/8 down from the edge (half material thickness) and 3/4 from edges, maybe one more for good measure in the center.
glue your joints with gorilla glue. This is a weak joint at this time, but sturdy enough for this aplication.
use care with gorilla glue, wear old clothes and don't glue the cab to the work table.
don't ask
screw your tops and bottoms to the sides, square up and clamp your cab and let dry over night.
buy a couple bags of FLUTED 1 1/4 dowels from Lowes or other such place. Fluted dowels are compressed and will swell when the glue is aplied making them even tighter. the flutes also allow glue to go past them. this is important because when you hammer them ever so gently into thier bores, the hydraulic action will not blow apart your wood.
don't ask
draw your scribe line between your screws 3/8 down from the edge. mark off where dowels will go, every 3/4 inch is about right, they may not be even. but no one will see after the covering is on.
chuck a 1/4" drill bit into your drill and measure 1 1/4 and attach a piece of tape as a depth guide.
work one side at a time, 1 hole at a time. leave the screws in, drill a hole,put some glue in, tap a dowel in, wash repeat rinse. use TITEBOND II, don't screw around with other glues, this works and works well.
after all the dowels are in, excess glue wiped off, let dry over night.
NOW you remove the screws, drill holes where the screws were and dowel them
IF you are careful you can trim the dowels that are sticking out with a SHARP chisel, but likely you'll experiment with a razor box knife(no way suggesting this).
Sand,fill with wood filler where needed,(most of the dowels), sand again when dry.
Use 1/2" roundover bit in your router on all outside edges, wood filler where needed and sand again.
use Denim material instead of tolex, it's cheap and rugged. glue down with spray on super 77 and it will last for years.
if you buy your denim on sale, $4
plywood for 1x12 cab $14
bottle of gorilla glue $5
bottle of titebond II $5
bag of dowels X2 $4
Super 77 $14
$ 46 total. can only be cheaper if you have any of these items already
This doesn't include baffle board or back boards.
believe me when I say this is STRONG, you're not skimping here, simple enough to get great results for a first timer with a table saw, router and a drill. might be able to sub a coffee mug for a hammer to drive the dowels, not recommended
Don't ask