Serving Trays
(Or any box-shaped project with mitered corners and miter keys)
As projects go, this one is so simple to build that detailed instructions may be overkill. There are techniques here, though, that are fundamental to any box-shaped project with mitered corners. Projects like this build knowledge and skill, and there is wonderfulness in the ability to make custom accessories that fit your personal needs. I have found that the simplest projects can have a profound impact on my woodworking and on daily conveniences and efficiencies, and these serving trays fall into both categories.
The impetus: We have three inexpensive trays that we use for dinners in front of the TV and for coffee/tea/snacks around the house. These are the type of things you get at Target or Pier One. Two are too large; more like the “breakfast in bed” affair you see in old movies with fold out legs. One is a good size, but as a single, it is in too much demand (translation: it is never available for my use). All are built cheaply and are out-of-context among our other furnishings and accessories. I decided it was time to take advantage of my ability to make a set of trays that suits us and how we use them.
My design decisions started with where these things were going to be stored. The trays we have are a pain to store. They’re always in the way and don’t stack nicely. I have a lower shelf on a serving bar with space just right for a set of nesting trays, so I designed my trays to fit on that shelf. The largest is about 15 ¼ X 15 ¼. That also happens to be a great size for a lap tray that will hold a dinner plate, beverage, tableware and maybe a side dish.
The next decision was based on use. There are two of us, so we need two lap trays we can use for dinner. But we also use the smaller of the trays we already own for drinks and snacks, and we seem to compete for it. It’s also a little large and cumbersome for a drink and a snack, so I thought maybe we would get more use out of
a couple half-sized trays. I settled on a set of four trays. The largest is 15 ¼ X 15 ¼, the medium tray fits inside the large tray and is 14 ¼ X 14 ¼. The two half-sized trays fit inside the medium tray, with exterior dimensions of 13 ¼ X 6 each. They nest, but loosely so that they can be pulled from the group at odd angles or with one hand. This is not a situation that warrants a piston fit.
I made my tray sides from 5/16” oak, because I had oak scraps on hand from another project. I made the tray bottoms from 3/32” Luaun, with cork shelf-liner attached with spray adhesive. The combined thickness of the Luaun and cork is exactly ¼”, which is convenient for milling. I avoided solid wood bottoms because they must be left loose in the frame for expansion. Ply material like Luaun doesn’t move, so it allows the bottom to be glued to the sides. This provides additional strength and eliminates rattles which is one thing I hate about my store-bought trays. Rattles sound cheap.
My thoughts on using cork- First off, I already owned it. I originally thought I would laminate the tray bottoms with some kind of grippy rubber sheeting, but then remembered I over-bought cork for a different project. Second, I checked it for its ability to prevent glasses and plates from sliding around and it is excellent. I also know cork is extremely durable and can be washed. The biggest advantage, though, is that it can take stain like any other wood product, and polyurethane, too. If you don’t overdo it, you can poly cork without making it slick. Cork’s a winner.
I started by laminating my cork shelf-liner onto a Luaun substrate and setting it aside. Then I milled my tray sides in the usual way. My sides are 2 ½ inches tall, which leaves plenty of room to cut in handles without weakening the sides. It is also helpful to leave enough material between the hand holes and the tray bottom so small things can’t fall out the sides of your trays.
I milled my tray sides from boards long enough so that all four sides could be cut from a single board. This allows the grain to be “wrapped” around the corners (three out of four, anyway), which is a nice touch on an item like this that will be handled up close. This is simple enough to do; just mark your boards as you mill them so you can match up your corners when it comes time to assemble the trays.
Next, I cut a shallow groove in all my sides that will fit my tray bottom laminate precisely. Then I cut the tray sides to their final length.
I opted for keyed miters on the corners. I tend to dovetail corners like these, but I think keyed miters have a more elegant appearance. Cutting miters can be tricky, so some care is warranted here. If you intend your joints to be glue-ready off the table saw, you’ll need to make sure your saw is tuned up, that your miter gauge is set square, and that your blade is tilted accurately. On tune-up, keep in mind that tilting a table saw blade introduces a third dimension (or plane) that must be in perfect adjustment for miters to come out accurately. Very little is said about shimming table saw tables front-to-back for this additional dimension, and if you have no idea what I’m talking about, do yourself a favor and find out. Roland Johnson describes how in Fine Woodworking, Issue 179, Page 46. http://www.finewoodworking.com/how-to/article/how-to-tune-up-your-tablesaw.aspx
Alternatively, you can rough-cut your miters by hand or machine and tune them up on a shooting board for miters. Regardless how you proceed, make sure every opposite side of each tray is the same length. Variations in length will mess up your miters just as badly as being out of square or off 45 degrees. Tight miters require all angles to come together harmoniously.
Next I cut the handles into the sides. I put handles on all four sides so that we never have to look for a handle. I cut my handles quite small, because a good grip equals fewer accidents and fewer carpet stains. After some trial and error, I settled on handle holes that were ¾” by 3”, a secure fit for my Sasquatch-sized hands, without being too sloppy for my wife’s hands-of-a-twelve-year-old. Using a Forstner bit, I drilled ¾” holes at the drill press, centered on each tray side from end to end and from top to top-of groove, 2 ¼” apart. I sawed out most of the waste between the holes with a dovetail saw, then routed out the remaining material at the router table using a straight fence. I finished the operation at the router table using an 1/8” radius bit with a guide bearing to ease all the edges of the hand holes for a comfortable grip.
With all tray sides milled square, grooved for the tray bottom, cut to length, pierced for holding and sporting perfect miters on every end, it’s time to do some pre-finishing. Avoid trying to finish sand and stain the inside of these trays after glue-up. The inside face of each side, plus both sides of the tray bottoms need to be completely finished (save perhaps for a coat or two of wipe-on poly) before glue-
up. Be careful sanding. Use a block to keep material removal level and consistent, and don’t over-do it! Sanding too aggressively (and unnecessarily) can throw your corners out of alignment on final assembly.
It’s time to assemble the trays. Referring to your marks for grain wrap, line up the four sides of a tray with the finished, insides facing down. Using a straight edge for registration, push two tray sides together and observe your beautiful gap-free joint. Stretch blue painters tape across the joint and repeat for 3 of your 4 corners. Flip the assembly, finished side up.
Using an acid brush, I applied glue to the tray groove and all the faces of the miter joints. Next, I inserted a tray bottom into one of the sides in the middle, then wrapped it up with the other three sides. The blue tape “clamps” should bring your miters tightly together on 3 sides, and the final side can be adjusted with a few light taps and taped shut. If everything was cut square and true, there should be no need to torture the tray into alignment, no ghastly clamp-a-palooza, and no gaps in your joints. If you Dagwood this glue-up, relax. There are probably tricks remaining to sweeten up your joints, and if they can’t be made to look perfect, at least they represent your own work and not the work of a child laborer in Bangladesh. Remember the point of this project is to have something functional and customized just for you.
One common problem with miters is a gap along the length of the joint, either because your miters are not exactly 45 degrees, or the 45 isn’t square to the stock, or the stock isn’t straight, or some other issue. Take heart. You can probably burnish your corners to close the gap. Those wood fibers at the sharp end of your miter cut are very thin and very flexible (and fragile). Small gaps along the joint’s length can be closed by bending those thin fibers toward one another with a burnishing tool or the smooth part of a 3/8” drill bit. Gently and patiently close the corner by drawing your burnisher out and across the joint. Try to move each edge equally toward the other. When your joint is nicely closed, secure and harden it with CY glue (a/k/a/ CYA glue).
The next step is to spline or “key” the corners. End-grain to end-grain joints are not strong enough for the daily use these trays will see. The mitered corners must be reinforced, and corner splines or keys will do the job with elegance.
If you don’t already have a jig to cut corner keys, it is time to make one. My jig fits the table saw. I’ve seen some guys do this with a 
slot cutter on a router table. My design may take a bit more time to make, but I can add sacrificial surfaces to the inside faces and use this for a lifetime, whereas a jig for a slot cutter, with its limited depth of cut, will chew up a jig over time and the whole jig will need replacement. Another option is to create some sort of attachment to a biscuit joiner. Choose your method.
I started by deciding how many keys would be needed to have strong, beautiful corners. I decided on 5, favoring an odd number so that one key would be dead center on the corner joint. Next, I worked out a distance between the keys that left me with enough material at the top and bottom of the corner to be strong and look good. I didn’t bother trying to get the same space between the keys and the top or bottom of the tray as between each key, but you can fuss around with the math until all keys are equally spaced if you wish. I ended up with 3/8” between each key, which left about 1/8” at the top and bottom.
Using a 1/8” dado cutter on my table saw adjusted to a depth well shy of cutting through my mitered corners and into the inside of the tray, I centered my first cut on each corner of each tray. I clamped a stop block to my jig to ensure consistency. After all my centered key grooves were cut, I marked the location of the stop block on the jig and moved the stop block ½” away from the blade, representing the 3/8” space between the keys plus the 1/8” thickness of the cutter. Then I cut all four corners of each tray twice, once with the tray bottom to the left of the stop block and once with the tray bottom to the right of the stop block. This added two grooves to every corner, each 3/8” from the center groove. Again, I marked the location of the stop block on the jig and moved it another ½” away from the cutter and repeated the operation, finishing the process of cutting 5 key slots on each corner.
Next, I milled the key material. I used some walnut scrap for contrast and started at the band saw, slicing off strips roughly ¾” wide and about 3/16” thick, jointing the material before each cut so that one side of the key material was always straight and smooth. Make lots. You don’t want to have to abandon a glue-up to make more keys. I used my planer to sneak up on a fit that was too tight by a hair. My machines are too violent to produce consistent thicknesses in material this light and thin. I left enough material so that every key would require a few strokes on sandpaper to achieve that lovely piston fit.
I used my crosscut sled to cut dozens of keys about an inch long, using a pencil with an eraser to hold the small pieces and clear them from the table saw blade. This operation takes care and attention to perform safely. If you aren’t comfortable doing this at the table saw, cut them by hand with a miter box or at the band saw.
I cleared space on my bench to glue keys (I had 80 to do all together), which included a piece of granite with adhesive sandpaper on it to “joint” the sides of my keys to a perfect fit. One by one, I sanded the sides of my keys to fit each groove, and I slide them into place with a drop of liquid hide glue- just enough to squeeze a bit out of each end of the key. I used hide glue for its long open time, which really helps in a future step, and I made sure every key was centered on the joint and proud of the tray side at each end.
Keys were curing as I was still gluing, and as a box would cure to a fairly firm tackiness, I would break from gluing to saw off the exposed keys. A very timely “Methods of Work” article was printed in Fine Woodworking #255, in which John Bates from Tampa described a method of trimming miter keys that worked great on this project. Basically, 
a guide board is clamped to the band saw, and the saw blade is recessed into the guide board. The blade is recessed deep enough into the guide board so that the project can be passed through the saw against the guide, trimming the keys without marring the side of the work. The guide board must be thin enough for the lowest key to pass over it. For these trays that required a guide board 1/8” thick. It worked great! I was able to quickly and accurately trim all 80 of my miter keys to within about 1/32”, leaving just a few strokes with a sanding block to level them.
Here’s that future step I referred to where using hide glue helps. Trim your miter keys while the glue is set but still gummy. Then use some cheap, coarse (80 or 100 grit) sandpaper to level your miter keys. You’ll have to change paper often due to glue build-up, but your sanding dust will be forced into any gaps and will be fused with the gummy hide glue. You’ll have perfect, gap free joints that match the surrounding wood. This works with PVA glue too, but PVA isn’t as forgiving as hide glue.
Here’s a trick to fix miters that didn’t come together at the top or bottom. Force some hide glue into the gap and let it get tacky, just as with the miter keys, then sand the corners to force dust into the glue. Unless your gap is as wide as the space between students at a middle-school dance, this should close the gaps.
After the trays cured fully, I finish-sanded the top, bottom and sides and applied the same finish I used for the inside. For projects like this one, I really like General Finishes gel stain, which is really a tinted gel polyurethane. I know these will be wiped down frequently with a damp cloth and will be exposed to other fluids from time to time, and so poly is the only finish I would consider. I like the satin finish of the stain by itself, but it is simple enough to add a few coats of wipe-on poly if shiny is your thing.
Viola. A wonderful set of functional, easy-to-store serving trays with elegant, keyed miter corners and grippy cork bottoms. These will provide us with a lifetime of use, and I can use everything I learned about making keyed miters for almost that long, too!
