In this instructable, I will show you how to create a mitered box with splines. All miter boxes will be created the same however, you can change placement of splines, hinges, etc. to meet your personal preferences. For the sake of this project I am showing you a finished Walnut Keepsake Box but, in many of the photos, I will be showing you a small maple with walnut splines Essential Oil Box. The building steps for both boxes are identical however, with a larger box you can add more detail and really customize it to your liking. Enjoy and good luck with your build!
Step 1: Measure, Measure, Measure
Figure out how large you want to box and remember you are going to be mitering the sides for 45 degrees.
Step 2: Cuting
Make the necessary cuts after you have measured. Depending on the size of your box, you will almost certainly have two different sizes of cuts to make for you front/back, and sides.
Tip: Get painters/masking tape and tape the sides together and the front/back together and make a cut on the table saw or miter saw to ensure perfect symmetry.
Step 3: Cut Your Miters, Dados, and Bottom
The Miter cuts can be done with a table saw with the blade set at 45 degrees or with a miter saw. Either way, set your distance and make your miter cuts.
The Dado cut (Not all the way through the wood) is made to inset the bottom of the box. I personally like to use 1/8" hobby balsa wood for the bottom since it is readily available and easy to work with. My advice, lay your wood pieces laying flat, miters facing the workbench, and match the grain, then plan how low you want your dado cut to be (Usually 1/8"+ from the bottom). Make your dado cuts.
The bottom is easy to make. After you have made your dado cuts and made sure that the dado cut is wide enough to be able to accommodate your bottom, do a mock fitting of the box on top of the wood you will use for your bottom. With a pencil, trace out the interior dimension of the box to the wood you will use for your bottom. Then, depending on how deep your cut your dado, add an 1/8" to the pencil trace. This will ensure a nice, clean fit to your bottom.
Step 4: Prep, Tape, Glue-up
Lay our all of your pieces (Front, Back, Sides, and bottom) in the orientation that you are going to glue them and with the miters facing the workbench. Verifying that your grain mates across the box (It just looks better) take your painters tape and line up the miters and tape the wood together.
Once the the pieces are connected together, flip the connected pieces over with the miters facing you. Take more painters tape and tape along side of the miters. This will aid in the cleaning up of the glue squeeze out. Trust me, THIS IS A MASSIVE HELP!
Everything should all be connected by the tape and act as one piece at this step. Grab the glue and start your glue-up. Once the glue is everywhere necessary, add your bottom and fold the box around the bottom. When you have folder all the pieces around the bottom, add a piece of painters tape to the two unconnected pieces to ensure a clean snug miter.
Step 5: Cut Your Splines
After the box has cured, figure out where you want your splines and make the cuts. After making the cuts, take a caliper and find the thickness of your table saw blade. This measurement will be used to cut the piece of wood to inlay into the spline cuts you just make.
Cut the wood you would like to use for the inlays and glue and set them into the spline cuts.
Note: Splines not only look amazing but, a miter joint is a very weak joint and splines will ensure a much more durable and rigid box that will last much longer.
Step 6: Glue Up the Top
The top is glued directly on the body of the box. You can choose any design you would like for the top. I have done it with solid wood, inlays, etc.
Step 7: Trim Splines, Clean Up Top
Trim the spline excess with a flush cut saw or any say you have at your disposal. Next, take a flush trim bit in your router and clean up any overhang you have after gluing the top of the box to the body of the box. This will ensure for a clean flush box top.
Step 8: Cut Box Top and Add Hinges
Cut off the box top using the table-saw. As for the hinges, there are several options out there. I personally prefer to buy long strips of Piano Hinges and cut off what I need. However, I have done it several ways. For the walnut box, I used a piano hinge and for the maple box I used a standard small brass hinges.
Figure out how much wood needs to be removed from the back top of the box by taking a caliper and finding the total width of the hinged. You can take that measurement and make a line on the back of your box which is where you need to cut to. Use a router and chisels to make the appropriate cuts or just chisels.
Step 9: Epoxy!
This is by far the best way I have found to make sure your top sits perfectly. Add your hinges to the box body after you have drilled the holes. Mix some epoxy and add it to the top part of the hinge that will make contact with the top of the box. Lay the top of the box on the hinges and add a little weight for some pressure. Let it cure for 30 min. Once it is cured, all you have to do it drill and add screws and you will have a perfect top!
Step 10: Done! Add Some Finish!
Now that the box is complete, add any kind of finish you prefer (I personally like wipe-on-poly). I also tend to add some felt to the interior of the box for a cleaner look!