I have been asked to build a humidor for a buddy of mine. I have never built a lidded box before and wanted a practice run with some left over material before the real thing. So, I set out to make a large lidded box with splined miters.
I had a large piece of poplar leftover from some project and also some birch plywood. The project started with milling the poplar and then ripping it to width. Next, I had to cut each piece to width at 45 degrees. I wish I would have taken a picture of this setup. I used a miter gage in the right hand miter slot to perform the cuts. A block is clamped against the fence to ensure I had the same size for each piece. Bump the piece against the block and push through with the miter gage.
Cutting Spline Grooves
After test fitting the pieces and ensuring everything is square, it was time to cut the grooves to accept the splines. I was going to make the splines out of 1/4 plywood, so the width of the spline groove had to match. I laid out some rough lines for the spline placement to get an idea of where to start cutting. A sacrificial fence is attached and then moved the fen very close the saw blade. It is still tilted at 45 degrees. I used my miter gage to push the stock through while keeping it against the fence. Imagine in the picture below the stock is against the fence as well as the miter gage. I cut all 8 grooves like this.
Then I moved the fence away by about a saw kerf and made a second pass. I had to raise the blade height a little bit after my trial cut to get it to match the first cut. I cut all 8 miters again. The third, and final pass was a trial and error type of cut. I wanted a nice snug fit of the spline, so I kept bumping the fence out and testing the fit. Once I had it dialed in, I cut all 8 miters with that setting. I should also mention that I had to raise the height of the blade again. This method worked really well even though using a miter gage and fence simultaneously is not usually preferred.
After three cuts here is the finished groove.
The material for the splines is plywood and I cut some strips to fit. I had to test the cut a few times before it was nice and tight.
The proportions seem about right for the spline, maybe they could have extended a bit wider, but it works.
Cutting Rabbets, Plywood, and Glue Up
The top and bottom of the box are made from 3/4 birch plywood. I figured I would leave the plywood proud and wrap it with some trim down the road. So, I cut a 3/8 wide X 3/8″ deep rabbet in the top and bottom of each side piece of poplar. After I cut the rabbets, I realized that my splines were too long and interfered with the rabbeted section. Easy Fix.
Next was to dry fit, clamp the box, and measure for the top and bottom. I measured, cut, and cut again to get the proper fit. I masked off the areas near the glue joints with masking tape to save myself some headaches down the road. After a few projects, I know scraping glue from internal corners is tough and leads to a poor finished product. I glued and clamped the 4 sides with splines, the top and bottom at the same time. I don’t think I will glue the top and bottom at the same time, next time.
Cutting Trim Pieces
While the box was drying in the clamps, I milled up some leftover walnut to use as the trim pieces. The pieces were a little thicker than 5/8″ thick after milling. I ripped the pieces down to roughly 3/4″ wide. I want the trim to wrap over top of the plywood edge. Like an upside down L shape. So, I cut a section of the walnut out to form a rabbet. I cut the rabbet with two passes on the table saw. One pass to cut the height, rotate the piece, reset the fence and one to cut the width.
Cutting the Box Apart
In order to form the lid and the box, the cube has to be cut apart. I did this on the table saw with some extra precaution. The saw blade height is set to the thickness as the sides of the box. The first and second cut is pretty straightforward. For the next two cuts, I added a small shim in the kerf cut and clamped it in place. The last thing I want to happen is to have the lid and base pinch the saw blade as its going through and damage either piece (or damage me).
After making the fourth cut, the box and lid are mostly free from each other. The internal masking tape was still holding it together with a couple sections of really thin wood bridging the gap.
Voila, two pieces!
Trim and Flush
I mitered all the trim pieces for the top and bottom of the box using my miter gage and table saw.
After cutting all the trim, I clamped it on.
I left the top in the clamps for a couple hours and then put the bottom in.
After the top was out of the clamps, I flushed up all the edges with a block plane. I also used a smoothing plane on a couple areas that needed a fair amount of stock removed.
In the process of flushing everything up. Note the block clamped on the “exit” side to avoid blowout.
I followed the same process for the bottom.
Mortising Hinges
I bought some cheap hinges from HD to use for this box. I should have found some nicer ones, but oh well. Also, I should have looked for hinges, that when closed, have leaves that are flush with one another. The ones I bought, have a gap between them the diameter of the pin.
Anyway, I laid out the hinges about 3″ from each side of the box and used a pencil to trace them.. I followed the line with a knife and chisel. I put a small 1/16″ bit in my trim router and set the depth to the thickness of the leaf and routed near the line. (this was a mistake). I had to set the depth even deeper since my hinge doesn’t close flush. I basically had to set the depth to half my pin diameter. After the routing, i cleaned it up with a chisel. Here are a couple of pictures I snapped.
I only drilled the center hole on each leaf and did a test fit. I had to adjust the mortise/hinge a bit to get the proper alignment and drilled the remaining holes and mounted the hinge. A few passes with a block plane cleaned up any small misalignment.
Sanding some more, and Finishing
