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I'm building a trophy. It will consist of two boxes...one slightly smaller than the other and stacked on top of one another.

I'm looking for suggestions on how to join the corners of the boxes so that the veneer is the only thing exposed on the 4 corners and top.

Thoughts?

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The simplest way to do this is with a simple miter joint. Miter all sides of your panels at 45°. You'll need a tablesaw to do this, or a very accurate circular saw with a straight cutting jig (i.e. a track saw). To visualize it, each panel will end up looking like a squashed flat top pyramid if you lay it down on its outer face.

It will be very difficult to get the miter perfect, especially if the boxes you're creating are rather large. Any gaps will be obvious since the layers of ply will be visible underneath the veneer. The corners will also be fairly sharp and fragile since you can't sand or rout them down without exposing the plies underneath. If the biggest dimension of the boxes is 11.25" or smaller, I'd just use a 1x12 instead of plywood.

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Then use a square block or beam at each corner on the interior when you're gluing and clamping the corners.

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Alternatively you could do this with a router and a router table to create a lock miter joint, and then the blocking inside the box would be unnecessary:

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Image source

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  • @Tester101 Thanks for the edit. You pulled the images right out of my brain! – Doresoom Aug 20 '14 at 11:02
  • Thanks. The picture with the additional wood in the corners is a great idea. Any tips on getting the miter perfect? I always find this challenging and was considering trying a router to cut my 45s. – Craig Aug 20 '14 at 13:15
  • @Craig, A router table would help with the accuracy of the miters. See my recent edit. You could also do this with a simple 45° chamfer bit instead of a lock miter and still use the blocking. The corners might get a bit tricky with that lock miter as well - that part's hard to visualize. You might have to try it on some scrap wood to get it right before moving on to your final workpiece. – Doresoom Aug 20 '14 at 13:25
  • Thanks for all the feedback. Much appreciated! I am going to try a 45° chamfer bit this weekend. Good thing is that I do have more than I need at moment so can afford a mistake or two. – Craig Aug 22 '14 at 15:17
  • Yes, locking miters are difficult to adjust, both in height and fence distance. An alternative would be a splined miter, or even biscuits (the small ones.) – TX Turner Jan 6 '15 at 14:59
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I would approach this a little differently. First I would make the box using a join that best fits the tools you have (Butt, dado, miter or dovetail). Once the box is together, sand so all the faces are smooth and the joint can't be felt. Now, get some veneer sheets (thin sheets of wood) and attach according to the instructions. Some will have adhesive backs, some you will need to glue.

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  • Thanks for the suggestion...it's a god one. But I would like to use the maple veneer plywood I have left over in my garage already. – Craig Aug 22 '14 at 15:13
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If you can make a precise miter, it does this fine. The trick is in making it precise enough, and gluing it without allowing it to slip.

There is a family of standard joints, either originated by or made famous by the Stickley company (who were trying to get quarter-sawn faces on all 4 sides of an oak leg), that help with the slipping-when-gluing aspect by adding a key to the surface.

A picture would be delightful here but I'm uncomfortable with the rights status (for me to post it here) of anything I can find, so go have a look around the web with that in mind.

I have also seen this done by making a VERY precise V-groove that does not QUITE go through the face veneer at each joint location, and then gluing and folding - the face veneer is continuous on 3 corners, which helps hold it from slipping and also looks "seamless." You'll have to judge whether this is within your tools and skills or not.

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  • Thanks. Any suggestions on how I can cut a precise miter? I always find this challenging. Was considering trying to use my router to cut the 45s. – Craig Aug 20 '14 at 13:16
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Like the other answers explain, mitered cuts is the way to do this. And using thicker plywood definitely makes all of this much more forgiving/easier. But even if you have real thin plywood, as long as you can "sneak up" on the right miter angle, it's not that hard to make this work.

Like the other answers mention, you need to get an accurate miter or it won't fit up right and the joint won't hold well. But it's not difficult to get "near-perfect miters" even on a real crappy saw with a miter setting (table, circular, radial, etc). You just need to sneak up to the correct angle. So, how do you do that?

Set your saw to what seems like 45 degrees. (You can use a carpenter's square, protractor, angle finder, etc to try to see if the saw blade is actually 45, but it doesn't matter). Cut two scraps of wood and fit them up on a flat table. Slap something square next to them and see if the pieces are really mating at 90 degrees. If they're not, adjust your miter, cut again, fit again, until it's pretty much dead on. Now you have a 45 degree miter.

If the angle still isn't perfect or the walls don't mate up perfectly, you do have two ways to "fix" the result.

  1. If the angle was too small (<45) you'll have a gap when the pieces are supposed to be at 90 to each other. To fix this, smear some wood filler (sand something with super fine sandpaper, then mix that sawdust with wood glue and a little water) on the pieces before you clamp and glue the box together. Make sure a little extra filler is coming out the gap. Once it's glued up, sand down the faces & corners. You'll get a super sharp corner and a layman won't be able to tell there was a gap filled.

  2. If the angle was too large (>45) then the edges will fit fine, but the inside of the joint will have a gap, so it won't hold together well. This has sort of a two-part fix.

    2.1. Make the bottom/top piece fit the walls. (If it's not apparent from the other answers, you need to make a mitered cut on the top/bottom of each wall piece, and then cut a new top/bottom piece with all its edges cut with the same miter). Cut the top/bottom piece so that it's slightly too big to fit up with the walls. Then slowly sneak up on the width/length until it fits. The walls will mate up to the top/bottom even if they don't mate up with each other.

    2.2. Use wood filler to fill the gaps on the inside where the walls connect. Since nobody's going to see this anyway, it shouldn't matter. If that doesn't hold, you can glue in the square piece of wood like in @Doresoom's answer. (I would cut the block into a triangle, so you can use one piece of wood to fit two corners; saves space/material).

If the plywood is thick enough, for a strong box, cut a dado into the bottom of the walls and slot & glue the bottom piece into the dado. Otherwise just edge-gluing a bottom piece into the inside bottom of the box won't be very strong. The top piece will always need to be mitered if you don't want any plywood banding to show.

I used all of these methods when making compound-angle trays out of only plywood and glue, because I suck both at math and at finding the right angle on my table saw. They came out pretty good, all things considered!

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