Looking for ideas

[Rich Engelhardt]

Again - I'm going to offer up using a lock miter bit.

Two problems:
1) I don't know if the pre-finished plywood will take glue. I suspect it won't.
2) These things have no joinery elements; they just fit together theoretically on paper. It looks like a difficult glue-up to get them to form a 5"-tall box with smooth sides. See the gaps in the photo.

#1 - the lock miter bit removes the finish - along with the wood - and leaves nothing but a glueable surface.
#2 - Lock miter joints are among the most simple to glue. You just tape and roll.

The downside of course is the hell you go through setting one up. That can easily be done though with the use of special tools that make it easy to do.

[Kevin Jenness]

A biscuit joiner would serve.

[Cameron Wood]

In the absence of air tools, I would glue and clamp the pieces, and afterward predrill and hand nail 4d finish nails.

Screws into the edge of plywood, especially 1/2", are likely to cause splits.

[Bob Jones 5443]

Update: the glue didn’t hold without first abrading (or removing) the finish. I’ll try sanding it off when I return to the shop in the week ahead.

One hope I hold out is to avoid needing to scrap the parts and recut them all in order to rout a lock miter. Recall that my blunder was to cut all the parts before I made a prototype. I’ve made this rookie mistake throughout my life. I’m waiting for wisdom to catch up to me.

Also I don’t own a biscuit jointer, but I’ve always made do by routing grooves for the biscuits. However, 1/2” ply is probably too thin for a biscuit.

I kind of like the predrilled 4d finish nail idea. I’ll look into that after sanding. I assume the glue will hold then.

I’m also set on making L-assemblies first (thanks Cameron). If you’re still with me, check out my clamping idea for them. With my crosscut sled in the miter tracks, I’ll line up four L-assemblies against it and press the rip fence against the other end, lock it down, and close up shop for the night. No clamps! I’ve already done this with another flat glue-up last week.Wacky but effective.

[Bill Dufour]

Micro pins and glue with some kind of biscuit or mitre groove.
Bill D