I make two kinds of box tops.
Boxes with inset tops (above) where the the top floats in a dadoed groove that runs around the sides,
and attached tops where the top is glued directly onto the sides of the box. This tutorial will feature the attached top method, and a press design to help with this process.
Of course you can use clamps to hold the top on until the glue sets. But I prefer this press.
The press features 8 all-thread sections with a compression spring and plastic pipe around the all-thread at each corner. The springs are meant to hold the press open so you can place a box inside without having to fight with the press.
So in this box the splines were glued in, the top has had glue applied and has had the rough top set on the box.
To save time I often will install the splines and add the top then I can let both of them cure at the same time.
Now it gets set into the press and then I use an impact driver to tighten the nuts and apply even pressure to the top.
This version has a welded metal lattice that keeps the all-thread from turning and strengthens the bottom plywood.
This shot demonstrates a 2×8 wooden cull added on top of the box top to make it easier to tighten in the press.
So now you can tighten the nuts with the impact driver and let the glue dry. Sure, you could use a ratchet wrench, but the impact driver is so much cooler and faster. I usually start at opposing corners and then move in and do a final re-tighten.
When the press is not being used, the press and some culls are stored on the shelf above the glue-up table.
-- Big Al in IN