How to build a finger jointed box with a hinged cribbage board top.
Step 1: Prepare Your Materials.
I used a cribbage board template from Rockler.com
The box entire box is made from 1/2" stock, except the bottom, which is 1/4". The template measures 5"x15", so that's how big I decided to make the board/top. The finished dimensions of the box are 16"L, 5"W, 2.5"H.
Cut your sides and ends 1/8" long. Cut your bottom 4-3/8"x 15-3/8". Determine which side of the wood you want on the outside. Sand the inside faces and both sides of the bottom.
Step 2: Cut Groove for Bottom of Box
Set up your table saw with a 1/4 dado blade, or your router table with a 1/4" up-spiral or straight cutting bit.
Set your depth at 1/4". Set your fence at 1/4", and cut your grooves at the bottom of your inside faces. Clean up any rough edges with sandpaper.
You'll want to use a sacrificial push block to avoid tear-out on the ends.
Step 3: Cut Your Finger Joints
I used a finger joint jig, also from Rockler, to make my cuts. You can buy one or make one, but either way there are tons of excellent finger joint jig tutorials out there that will show you how to use it, all way better than I can explain here. If you're a masochist, use a nice saw and a chisel :)
On the ends, your bottom-most cuts should be only 5/16" deep. This way you won't need to make little pegs to fill the holes that would be left by the slots cut in your sides. Set your depth at 9/16" for the remaining cuts.
Test fit your pieces. Everything should fit together well, with room for the bottom to float.
Step 4: Glue It Up.
Using a small brush, spread a thin, even layer of glue on all of the finger joints. Try not to get any in the groove for the bottom: it needs to expand and contract freely.
Assemble the box. Drop the top in place to keep it square, and use a strap clamp to pull it all together. You can buy finger joint cauls to accommodate the protruding joint ends, or use some scraps of 1/4" stock on each side of the corners, outside of the joints.
Allow to dry overnight.
Step 5: Make the Board.
Remove the top from your box and use some painters tape to secure the template to it. Set up your drill press with a #10 self-centering drill bit. Set your depth so you don't go all the way through your board. Drill 257 holes.
You don't need a self centering bit or a drill press, but the template is made for the bit and a drill press makes consistent depths a breeze. Your holes will wander all over the place if you don't use a self centering bit. Even with one it demands precision.
Depending on the hardness of your top stock and the length of your bit you may want to consider clamping a thin piece of wood or veneer/laminate between your top and the template to ensure cleaner holes.
You need to round the bottom rear side of the board so it will swing on the hinge pins: Set up your router table with a 1/4" round-over bit. Use several passes, raising the bit each time, until you reach the full depth of cut.
Step 6: Sanding.
Secure the top on the box with a few pieces of painters tape or clamps. Use 80 grit sandpaper to level the protruding ends of your joints and to smooth any differences between the box and the top. Move tape/clamps as necessary.
If you have any gaps between your finger joints, fill with wood putty (or a mixture of a little wood glue with some sanding dust) and allow to dry for at least a few hours.
Use 160 grit, then 220 to get a fine, smooth surface. I like to use a random orbit sander for the big work, and work my way down to hand sanding for the finer stuff.
Sand a little depression in the middle of the top of the front side, under the lid.
Step 7: Final Assembly.
Secure your top in your box with tape or clamps. Using a 9/64" tapered drill bit, carefully drill a straight level hole, 1/4" in from the top and back, through the end and into the lid, on both ends of the box. Sand smooth.
Push a piece of 1/8" brass rod into each hole until it stops with minimal effort. If you rounded the bottom edge of the lid and set your hinge pins properly, the lid should now swing easily and hold itself open standing upright. Check the top for smooth operation and sand as necessary.
Mark the rod 1/4 longer than the insertion depth, remove, and cut to length. Re-insert the new hinge pin, and use a mallet and a punch to drive the pin in until it is just below the surface of the end of the box. Repeat for other end.
Finish the box with two coats of Danish Oil finish. Enjoy your awesome new cribbage board!