Looking for ideas

[Bob Jones 5443]

Get your thinking cap on.

I need to make 16 little box-like sheaths that will act as footings for vertical 1x4s. Each sheath will be fastened to a 22"-long ski-like base. To help you visualize this, the upright 1x4s form the two sides of eight H-shaped stands (39" tall x 25" wide). The stands will fit into the footings, which will in turn prevent the stands from tipping over front-to-back under the light load they will bear. In the photo, there's a short length of 1x4 fitted into a mock-up of a footing. The footing is 5" tall. Its sides are 3-1/2" wide and its ends are 1-3/4" wide (inside dimensions are 3/4" x 3-1/2"). The footing is intended to fit closely around the 1x4. The plan is that I'll set two feet on the floor and insert the sides of an H-shaped stand down into them.

footing mock-up.jpg

So much for plans. I was so excited about figuring out the configuration of this contraption that I gave no thought to how I would join the parts of the footings. I designed the parts to be made from 1/2-inch plywood, and I eagerly cut all 80 (!) parts last night. I used a pre-finished sheet of 1/2" ply left over from cabinets I'm building.

Once I had all the parts cut, I was chagrinned to see that assembling them into boxes looks impossible, or impractical at best.

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.

One option I'm considering is clamping the box parts together and joining them with #6 screws (no glue), and then screwing them to the base up from the bottom. That might be the most practical way to use all these parts. But it will be a wobbly, fussy procedure.

While I slept on it, I thought about making the footing parts again, but this time with 1/2 MDF, and adding rabbets to the vertical sides of the end parts to register the side parts into them and make it more stable for glue-up.

If any of this makes sense, here's where you come in. How would you make these footings?

[Jimmy Harris]

How I would do it, is cut notches out of the base for the side panels to fit into, so they sit flush with the sides and bottom of the base, and then cut the front and back of the sheaths shorter and rest them on top of the base, so they all sit flush with at the top, and it's keyed in by the sides.

But, the real question is, how much strength do you really need? The good thing about plywood is, you always get a little end grain to end grain when you glue it up. So it's usually a little more forgiving for butt joints than regular wood. So, if you're not needing a ton of strength, you might be able to get away with just removing the finish where the joints meet (maybe a card scraper?) and gluing like normal. Maybe use some screws or nails to reinforce the joint (probably a good idea anyway, since there are so many and that would either be a lot of time or a lot of clamps). Or if you don't need the full height but need more a little more strength, maybe route a rabbet and dado into the base to accept the sheath. Or cut some small mortise and tenons on the ends to align them into your board. Or, if you do need the full height, you could use dowels or maybe small dominoes to reinforce the joints.

Lots of options are still on the table depending on what exactly you need, how much time you want to put into it, and what tools you have handy and are good with.

[Cameron Wood]

Glue and 1/4" crown pneumatic staples. Scuff the prefinished glue surfaces with coarse sandpaper and don't worry about it.

I would rig up something to hold two pieces in position, and assemble all the L shaped parts first, then clean any glue and assemble those into the rectangles.

[Bob Jones 5443]

Both useful ideas so far. Got me thinking. Any others?

[Kent A Bathurst]

Fire up that router your sticks are sitting on. On the box end pieces, make two quick passes to create very shallow rabbets for the long box sides to fit into. Get out the glue, and glue them up.

Then - shave off a bit of of the 1 x 4 standards with a hand plane to accommodate the rabbet loss in 3-1/2" dimension.

[Rich Engelhardt]

Router and lock miter bit?

[Lee Schierer]

I would drill pilot holes and counter sinks on the end pieces and use SPAX # 8 x 1-1/2" screws. Probably at least three per joint. Use the same screws to hold the "boxes" to the base.

[Kent A Bathurst]

I would drill pilot holes and counter sinks on the end pieces and use SPAX # 8 x 1-1/2" screws. Probably at least three per joint. Use the same screws to hold the "boxes" to the base.

I like Lee's idea better than mine. Assuming showing the screw heads isn't an aesthetic/grooming violation.

[Bob Jones 5443]

Of all the many reasons I love SMC, one stands out for me today: this community has your back. Every day someone is offering their guidance and knowledge to help someone work through an issue.

I can’t tell you how grateful I feel for those who’ve chipped in their slant on my little dilemma. Thank you.

My shop has no pneumatic stapler, no Domino, but I do have lots of other gear. As of now, the two ideas that have risen to the top are the L-shape subassembly and the shallow endpiece rabbets with shaved 1x4 ends. Each idea is simple but brilliant. This problem will be solved by the least onerous assembly method, and both of those ideas greatly simplify the process.

Right now I have a glued L-shape curing in my shoulder vise. I didn’t scuff the pre-finish off: if it holds, I won’t need to, and if it doesn’t, I’ll do that next.

While the glue dries, I’m still open to anything I haven’t considered yet.

[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

[Bob Jones 5443]

What’s a micro pin?