|Project by coloradoclimber||posted 10-14-2007 06:34 AM||20086 views||200 times favorited||36 comments|
About this time last year a friend showed me a little wooden box she had. She knows I’m a woodworker and she said “I’ll bet you can make these”. I took a quick look and thought, yeah, these look pretty simple, I probably could. My next thought was, hmm, christmas is coming up, and I need some presents, and these little boxes look pretty simple and pretty cool…..
And so a whole batch of little boxes were born. Unfortunately I gave most of them away without taking any pictures. They were a huge hit with the ladies, young and old, from little girls to little old ladies, they all delighted in these little boxes. Then you tell them these boxes are called “secret boxes”, their eyes light up.
So with christmas coming up again I cant really make and give these away again (the bar gets higher every year) but I thought some of you LumberJocks might be interested.
These boxes are called secret boxes, I understand the name comes from the idea that if you use the same wood for the lid as the body the lid becomes hard to see and supposedly not obvious how to open (seemed pretty obvious to me, and to the little ladies, one and all). So not so secret but everyone still likes the idea.
The box is basically a hogged out piece of wood with a sliding dovetail for a lid. The box itself is dirt simple. Take a piece of wood, hog out the center, cut a sliding dovetail, make a dovetail lid, assemble, done.
I made two sizes of boxes, the big ones are about 3/4×2 x 5 inches or so. The small boxes about 3/4×2 x 2 inches. The lids are about 3/16 thick.
Since I was going to make a bunch of them I decided I needed a jig or two. The trick to make this more of a production operation is to make a jig to hold the boxes for hollowing them out. The jig is made out of a piece of milled square 2×4 cut to the same length as the box with a groove cut in it the same depth as the box. You then screw a router template to the top and you have a hollowing jig to hog out the centers. I’ll get to the jig in a second.
First you start out with raw blocks of wood milled to the final outside dimensions of your box and final thickness of your lid. Contrasting wood for the lid really stands out.
Step 1: Cut the groove for the lid into the body of the box. Cut the groove a little narrower than the narrow part of the dovetail of the lid. I used a straight bit in a router table. You could very easily use a dado blade if you have one that cuts a flat bottom. Now you have a block of wood for the body with a groove cut in it about 3/16 of an inch deep (the thickness of the lid) and (for my boxes) maybe an inch and quarter wide, right down the center of the box. I used my router table, a straight bit, my fence, and a captured cut. I know, I know, I know, no captured cuts (if you don’t know what a captured cut is google it. It’ll probably tell you not to do it). And yes a couple boxes did get away from me and got ruined. If you’re gonna do a captured cut for goodness sake use pushblocks and keep your fingers back.
Step 2: I suggest hollowing out the inside of the box next, before cutting the dovetail. Once you cut the dovetail you’re going to have a nice sharp dovetail edge. If you cut the dovetails first and then hog out the box you run the risk of dinging the dovetail edges and it really ruins the clean joint.
To hollow out the boxes I made a simple jig / template for a hand held plunge router. The jig consists of a milled square piece of 2×4 cut to the length of the box with a groove cut in the middle just barely larger than the outside dimension of the box. A router template is screwed to the top of the 2×4.
To use the jig the box is slid into the jig from the end
The jig is then clamped into your bench vise. Clamping in your bench vise serves two purposes. First the whole jig and box are rigidly held so you can route it. Second the jig sides are flexible enough that clamping the jig compresses the jig sides and clamps the box tightly in the jig.
The template needs to be exactly centered over the groove in the 2×4. It should be exactly centered front to back and side to side. OK, not really. Since I couldn’t get the template exactly centered over the groove I cheated and made the jig adjustable. Lengthwise the jig is not a problem. The box can be slid from end to end until it is centered under the template cutout. When the jig is clamped in the bench vise the box will be held in place. For side to side adjustment I cut the groove in the jig about a 1/16 to 1/8 over size and used shims to center the box. I used some thin wood slivers and some strips from some old business cards to get the boxes exactly centered under the template cutout. Just stack up enough shims on either side until you get the box centered. Once you figure out the shim sizes for the stack of boxes you have milled up it’s pretty fast and repeatable.
Once I had the jig and box clamped in the bench vise I used a 1/4 inch solid carbide up cut spiral straight bit and a router bushing sized to the template cut out. I used a plunge router with a turret stops and routed out the box in a series of maybe 3/16 ths of an inch increments. Plunge the router, route out the interior of the box within the template, lift up, rotate turret to next depth increment, repeat. Keep going until you’ve routed down to leave yourself about 1/8 th of an inch thick bottom in the box.
So now you’ve got a box, with a groove where the dovetail is going to be, and the cavity of the box hollowed out.
Step 3: Cut the dovetails in the box. I used a 14 degree dovetail bit mounted in my router table. In order to get exactly the same cut on both sides of the box I did a captured cut between the bit and fence. The fence references the side of the box and the thickness of the dovetails to the edge of the box is the same on both sides. Again, use push blocks and caution if you choose to use this method.
Now the box body is pretty much done. The box is hollowed out and the dovetail is cut in the box.
Now to make the lid. To make the lid I picked a contrasting wood. The one shown here is maple for the box body and zebrawood for the lid. Maple and bloodwood was my favorite.
Step 4: I first cut a block of wood from some 4/4 stock just a bit over the lid width, maybe 1 and 3/4 of an inch wide. I jointed one surface and edge and resawed a strip maybe a 1/4 of an inch thick. I then planed it down to the final thickness, about 3/16 ths of an inch. I then took that strip of wood to the table saw and ripped it to just a hair over the final maximum width of the lid at the widest part of the dovetail.
Back at the router table, with the 14 degree dovetail bit still in place I routed down the edges. I did a standard cut with the fence to guide me. I had the fence moved out to just expose enough of the bit to just cut the dovetail. Once you have the dovetail cut you start fitting it to the box. I cut my lids slightly oversized and made multiple passes over the dovetail bit, just barely trimming the lid, until I got a perfect fit.
A perfect fit, that requires a comment. What is a perfect fit? A perfect fit is one that is snug enough that the lid stays firmly in place when the box is tipped, that provides firm resistance when closed, but is not so snug that when the wood swells the next summer the lid gets firmly wedged in place. You might wonder how I know this. Well along about the next spring I was back in the shop doing some lid tuning so the recipients of these boxes could get the lids off. As soon as the lids swelled they wedged TIGHT. They were tough to get out. I just hope I didn’t trim off so much that come next winter they don’t shrink so much the lids fall out.
Step 5: Now that the lid is dovetailed to a perfect fit, cut it to length and slide it into the box. Take the box with the lid in place and treat the box outside edges as you want. I used a 1/2 inch radius round over bit in my router table and went all around the outside edges of the box. If you route the edges do it with the lid in place. This insures the lid edge treatment is a perfect fit with the rest of the box.
Here’s roughly the workflow:
- Decide the dimensions of your box and lid and make a jig / template.
- Cut and mill a stack of blanks for the box bodies.
- Cut and mill a stack of blanks for the box lids.
- Groove the top of the boxes for the lids, slightly undersize. Router table with straight bit or flat bottomed dado blade.
- Plunge route the box, hollowing out the box body.
- Dovetail the box for the lid. Router table with dovetail bit.
- Dovetail the lid. Slightly oversize and work you way down to a perfect fit making multiple passes.
- Trim the lid to length.
- Edge treat the entire box. Router table with round over bit.
And there you have it. If you make a jig and set yourself up with a planned workflow you can crank out a stack of these boxes in pretty short order. Hey! Christmas is only a couple months away, you better quit sitting here reading and get out in the shop and start making boxes!!