Side order

I finally got back in the shop last weekend and made some real progress. The front, back, and legs are basically done, so now I'm focused on the sides. Each side will consist of a cherry frame with solid maple panels. Both the top and bottom are curved, so the joints are tricky; plus, the side must fit perfectly between the front and back, which are also curved.

I started out making a template for the top rail, which curves from the back leg down to the front leg. My idea was to set up the legs on a piece of construction paper and draw in the shape I want. I cut out the paper and used it as a template to cut the rails (two of them; one left and one right). The trickiest part is that the ends of these rails need to be curved to fit the curves of the legs.

Next I cut the bottom rail, which is simpler because at least one edge is straight. Finally, I cut three styles for each side panel -- a left, right, and middle. The next step will be to cut mortise and tenon joints to assemble the frame. Again, the tricky part is that the top joints are not square (more details to come soon!)

Before cutting the frame joints, though, I decided to make the maple panels. Each panel will be about 12 inches wide, 27 inches tall, and 1/2 inch thick. These specs present two problems. First, my jointer is only 6 inches wide, so I can't joint a single 12 inch board. Second, 1/2 inch thick stock is not readily available.

The next six photos show the process of making these panels. I started with a single large 10 inch wide 6/4 maple board, which I cut into six equal size boards. Each little board is about 5 inches wide, so they will fit on the jointer. Then I resawed each board (sliced the board) using the band saw to produce two 3/4 inch thick rough boards. Finally, I rejointed and thickness planed each board down to 1/2 inch. I now have 12 boards, each one is 5 inches wide, 27 inches long, 1/2 inch thick.



These last two pictures show the parts of the side panel assembled roughly as I'm hoping them to look. Once I cut the joints for the frame, I'll cut a groove along the inside edge of the rails and styles to hold the maple panels. Eventually, I'll cut a moon and stars in the panels.

On the Rails

The last couple of days in the shop I focused on the top rails of the front and back. In the previous post you can see that each rail is a slab of cherry 6" wide and about 1 1/2" thick. In the design these rails curve forward and backward to match the curve of the legs. The rails are then attached to the slat assemblies.

Shaping the rails involved several steps. First, I made a 12 degree cut on the edge of each rail so that when butted against the slat assembly the sit at the proper angle. At this point, though, the faces are still flat. Next I made two very shallow angled cuts on the face of each board that roughly follow the intended curve. Then I used a combination of planing and sanding to finish the curve.




Attaching the rail to the slat assembly presents a challenge. The joint needs to be strong, but it's difficult to clamp because of the angle. My solution is to use a spline. First I cut a 3/8" groove in the mating edges of both parts. I then cut a strip of hard maple (the spline) to join the two pieces. The spline not only strengthens the joint, it also helps keep the parts aligned during clamping.

Here are a few pictures of the front with the legs -- it's really starting to look like a bed! Tomorrow I'll glue the rails and finish shaping the legs.

New Posts

It's been a couple of weeks since my last post, but I have been working on the crib. In fact, I made the posts!


Each post starts out as a slab of cherry 4 inches wide and about 2 inches thick (a "blank"). In order to make sure that the front and back fit I decided to lay out the shape of the post with the other parts in place. In the first three photos you can see that I clamped the front and top rail where they should be on the post blank. Notice that the top rail will be curved, so I'm positioning it in the outline of that curve on the post blank.



Using the position of the front parts as a guide I made a template for the curve of the foot. I copied that onto all four posts, using a slightly shorter version for the tops of the posts. I cut along those lines on the bandsaw.


After look at the results I felt like the posts were a little boring, so I decided to add a secondary curve on the inside of the foot. This cut can be a problem on the bandsaw because the foot is no longer properly supported. I learned a nice trick to solve this problem in a woodworking class: tape the cutoffs from the first curve back onto the piece, making it look like a whole blank again. Then make the secondary cut. Tomorrow I'll post pictures of the finished legs. Needless to say it takes a lot of scraping and sanding to get the resulting curves smooth.

Glimmers

Last weekend was a mixed bag. On the one hand I struggled to get two more good-quality coats of lacquer on the slats. On the other hand I finally glued the slats into the top and bottom rails -- the first assembled (and recognizable!) parts of the crib.

Saturday was a warm humid day, and as the sun beat down the water-based spray lacquer became more and more temperamental. I sprayed a couple of fairly ugly coats that dried too fast. I had to sand them smooth, which was a huge pain (see photo of lots of wet/dry sandpaper). I finally got a nice finish coat, which I sanded one more time with 800 grit wet/dry sandpaper, and polished with super-fine steel wool. The surface is silky smooth.

The glue-up was a little tricky, since it involves putting glue on 14 mortise and tenon joints and then getting the whole thing lined up before the glue starts to set. It went remarkably smoothly and I was able to set the clamps in plenty of time.

Here are the resulting front and back panels of the crib -- note that the cherry is not finished yet, so it looks pale and somewhat cool next to the maple. Once the rest of the crib is done I'll finish the cherry with shellac and probably a coat or two of water-based varnish for durability.

Notice that the bottom rail of the front is curved. I cut this curve after cutting and fitting all the joints, but before gluing. This is all fine and well, except that the curve makes it very hard to clamp the assembly. One neat trick I learned is to save the cut-off piece from the curve cut and use it as a brace for the clamps. It fits perfectly and squares up the bottom rail. The next step will be to shape and attach the decorative top rails that curve forward and backward to give the "sleigh" shape.

Finish before you start

Every now and again I manage to learn from a previous mistake and do it right the next time. In this case I realized that it would be much easier to pre-finish the slats than to finish them after assembly. I also realized that I might want to use different finishes for the slats, since they're maple and the rest is cherry. I decided to spray them with water-based lacquer -- Target Coatings makes a fantastic product called USL. Water-based finishes are nice because they clean up easily, are non-toxic, and safe to spray without crazy equipment (like "explosion-proof exhaust fans".)

In order to make spraying easy I came up with this set-up: the slats are held in a frame made of scrap wood. I can easily spray them all at the same time, but then disassemble it to sand between coats. In addition, the scrap pieces cover the tenons so that they don't get finish on them.

I started out with a thinned-out coat to seal the wood and penetrate for better "popping" of the grain. I also added a tiny bit of aniline dye stain (from J.E. Moser's) directly to the finish to compensate for a common problem with water-based finished -- unlike solvent-based finishes, they impart no yellow color and can make wood look cold.

I sprayed a total of four coats of USL using my HVLP (high-volume, low-pressure) spray system. I bought a 3-turbine machine several years ago from American Turbine -- it was pretty expensive considering that it's basically a glorified vacuum cleaner with a hose and a spray gun attached. The lacquer goes on easily and dries fast.


All in all I'm pretty happy with the results. Look at that grain! I'll probably sand them again and add two more coats tomorrow -- just because.

Shaping the slats

After I finished cutting, joining, and sanding the slats I noticed something about them: they have very sharp edges. "Sharp" is not a good property for kid's furniture. I decided to break the edges by adding a chamfer along the edge. I like a chamfer better than rounding -- it looks more refined.




Ordinarily I'd add a chamfer either by sanding, or using a block plane. But I've got 28 slats to shape, each with four edges -- that's 112 edges to chamfer! I need the process to be quick and produce a uniform chamfer on all edges. The ideal tool for this job is a router table with a chamfering bit. Since I don't have a router table and the parts are small, I clamped the router upside down in my bench vise.

This set up worked really well, and all I had to do afterwords was lightly sand the edge to clean it up.

40 Hours in the Desert

Sanding. Ug. It's loud, dusty, and boring. But it's got to be done. Last weekend I made one pass over all the slats with P150 using my random orbit sander. P150 is good place to start to remove mill marks from the planer and sand away any tear-out in the curly maple. I still need to go to P220, and probably down to P320 before applying the finish.

So far I've been very careful to mark the slats, so that adjacent slats come from adjacent parts of the original board, and so that all the slats are oriented the same way. To this end I numbered the slats before they were cut, and marked each one with arrows indicating its final orientation. The problem now is that I need to sand the entire surface, including the markings. To solve this problem I transferred each number to the end of the bottom tenon, oriented so that outer face of the slat is up when the number is up. Obsessive? Perhaps. But I think it will pay off.

The next step is to glue the slats into the top and bottom rails. Once glued, however, the slats will be difficult to finish. So, my plan is to pre-finish them with two coats of shellac before they are glued, which will be much easier. The last picture shows a test strip finished with shellac on the top and boiled linseed oil on the bottom. I think the BLO is too yellow and doesn't pop the figure more than shellac. Plus, shellac is totally non-toxic -- in fact, it's used as a coating on foods, such as candy.

56 Bottles of Beer on the Wall

Last weekend I made good progress on the front and back of the crib. These two parts are similar in that they both consist of cherry rails connected by a number of curly maple slats. How many slats, you ask? 14 -- on each side. That's a total of 28 slats, and each one needs two mortise and tenon joints (for the top and bottom.) So, that's 56 mortise and tenon joints to cut.

56 mortises is a job for a dedicated mortising machine, which performs the magical task of drilling a square hole. I bought this machine a while ago because I got sick of cutting mortises with a router, which requires a complex jig and results in a rounded mortise. A bench-top mortiser is essentially a drill press with a special hollow chisel bit that attaches to the head. Inside the hollow chisel is an auger bit that drills a circular hole -- the chisel on the outside squares up the hole.

Even with the mortising machine it takes a while to cut 56. The third picture shows the four rails, each with 14 mortises. The narrow rail is the top and the wide rail is the bottom. The wide rails will eventually be cut with a curve, but it's easier to clamp the joint before the curve is cut.

The next step is to cut tenons on each of the slats. Again, we've got 56 joints to cut, so it needs to be efficient. I could have used my table saw tenoning jig, which produces very nice tenons, but would take forever. Instead I set up the table saw with a dado blade, which is much faster, but cuts a fairly rough tenon. The last two photos show one mortise and tenon -- not a bad fit!

The bars

Last weekend I finally got back to work on the crib: I cut the curly maple boards into strips that will become the slats. The band saw is a great tool for this job. First, the blade is thin and leaves a very narrow kerf, so very little wood is wasted. Second, it's simpler to cut uniform strips without a complex and dangerous set up, as would be required on the table saw.

The band saw jig is very simple: it consists of a wood strip cut to a rounded point at one end. The strip is clamped to the band saw table with distance between the tip and blade set to the width of the slat. The trick is that as long as the left side of the board touches the point, the slat will come out the right width, even if I don't hold the board perfectly straight.

The only downside of the band saw is that the resulting edge is rough. After each slat is cut, I re-joint the edge of the board before I cut the next slat. Once all the slats are cut I use the planer to get a smooth surface on both sides. The third picture shows a set of slats (for the front) all cut and planed.

In the last picture you can get a sense of what the front and back of the crib will look like with the rails and slats in place. Notice that I cut the slats from 6/4 curly maple, so the side of the board becomes the face of the slat (which is 5/8" thick). The next step will be to cut mortise and tenon joints along the top and bottom of the rails.