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.

518037

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?

[Rich Engelhardt]

(I'm thinking micro pin = 23 ga.)

Anyhow - I got it about the lock miter and not wanting to change dimensions.

I did a little looking about prefinished plywood and it looks like it can be painted, just so long as it gets scuff sanded first.
If it can be painted, then it can be glued.

I kept looking and it looks like some people have had success using Roo Glue.

[Jim Becker]

What’s a micro pin?
23 gage pin nailer

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Pre-finished ply often has a factory applied polyester finish on it so PVA type glues are not going to work at all without removal or "substantial" abrasion. You might get away with polyurethane glue or epoxy, but abrasion will still be a good idea, if not actually required.

[Bob Jones 5443]

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.

Kent, that did it. I routed off about 0.015" deep along the ends of the narrow end parts. The 1/2" ply is about 0.475", so that's how wide the rabbets are. The tiny shelf actually helps register the wide side parts and prevents them from slipping inward during glue-up. They's so shallow that I wonder if I'll even need to plane off the 1x4s.

Genius.

[Kent A Bathurst]

Bob - cool beans. Glad you have a repeatable solution that you're comfortable with. I was wondering if that would provide a lip/shelf to help in alignment. That's pretty neat for your project

Nothing genius about it - I have spent 3+ decades overcoming mistakes. In fact, I don't do too much design on pieces anymore - I just tee it up, and mistake my way to a finished product.

I'm hoping to see a finished product - there's something going in those "H-stands" and its driving me nuts wondering what. Unless it's political adverts, in which case I'm full up.

[Steve Demuth]

Since you've got something from Kent that works for you, this answer is redundant, but my solution would have been to make or buy a bunch of 3/16" dowel stock, set the boxes up on a jig in the drill press and drill for the dowels straight through the end pieces into the side pieces, then glue and hammer in the dowels. Three dowels per joint would be about right. I've used this technique on drawer sides before. You basically get a poor man's box joint using common tools and manageable effort that's plenty strong for most ordinary purposes.

[George Yetka]

Lock miter 2 sizes of ply strips you can make this 4' long or whatever you feel comfortable with working. Then glue and pin nail then chop to your length. The box will be plenty strong. Then screw from the bottom of your floor piece into the box.

[Bob Jones 5443]

George, ganging them as you suggest is a very good idea. Wish I’d thought of that before I cut all the individual parts!

Notably, I did gang two other small parts for this grand design:

1) 1/4 x 1/4 x 3/8 buttons glued to an 1/8” thick 1/4 x 1” base. I needed 16 of these little guys, so I made one long strip and crosscut them 1/4” wide.

2) a 3” long (wide, really) maple hook made of a 3/8” bar glued to the 3/8 x 3/4” hook piece. Again, I glued two 14” long strips and crosscut them into eight 3” parts.

Now Kent is really curious!

[Bob Jones 5443]

Since you've got something from Kent that works for you, this answer is redundant, but my solution would have been to make or buy a bunch of 3/16" dowel stock, set the boxes up on a jig in the drill press and drill for the dowels straight through the end pieces into the side pieces, then glue and hammer in the dowels. Three dowels per joint would be about right. I've used this technique on drawer sides before. You basically get a poor man's box joint using common tools and manageable effort that's plenty strong for most ordinary purposes.

Steve, I’m not sure I would have been able to hold the mating parts together firmly enough to drill through them, but if I could have worked that out, it would be a good method.

[Bob Jones 5443]

Bob - cool beans. Glad you have a repeatable solution that you're comfortable with. I was wondering if that would provide a lip/shelf to help in alignment. That's pretty neat for your project

Nothing genius about it - I have spent 3+ decades overcoming mistakes. In fact, I don't do too much design on pieces anymore - I just tee it up, and mistake my way to a finished product.

I'm hoping to see a finished product - there's something going in those "H-stands" and it’s driving me nuts wondering what. Unless it's political adverts, in which case I'm full up.

Non-political, I promise.

I’ll keep you guessing until I can post a photo of the finished item.