How to Design and Build a Crib General Woodworking
Don Heisz is the author of Offcuts, a weekly article on the lighter side of woodworking.
There are few occasions that inspire the potential builder more than the immanent birth of a baby. I am no exception, and since I am due to have a new child in March, last month I decided to make a crib.
There are strict governmental guidelines regarding the construction and design of cribs. In Canada, on the government’s website, the regulations can be found in SOR/2010-261. The details I was most concerned to find were the spacing of bars and the height of the mattress.
This project is a good example of one that requires fairly careful planning. More than just having enough material and a rough-and-ready plan (my version usually scrawled on a single piece of paper), in this instance there cannot be any last-second design choices. So I advise not only planning every detail carefully but you should also but the mattress and base the dimensions off its size.
The space between the slats or bars cannot exceed two and three-eighths inches. I made them slightly closer together, at two and one-eighth. I decided to have three sides made using frame and panel construction and one side with bars. The bars I chose were 5/8 inch dowels. They are easy to find and strong enough for this use. Plus, you need only drill a 5/8 inch hole to properly glue them into a rail. These dowels, by regulations, are not allowed to turn or move in any way.
I decided that there should only be two mattress heights. The lowest position has to have the bottom of the mattress at least 26 inches from the lowest point of the top of the crib. The highest position has to have the mattress at least 9 inches from the lowest point of the top of the crib.
I settled on poplar for the frame construction and 1/4 inch mdf for the panels, because it makes a perfect flat panel for painting. I also chose 1/2 inch mdf for the mattress support.
The material list ends up being not very expensive: 1 sheet of 1/2 inch mdf, 1 sheet of 1/4 inch mdf, 5 8-foot lengths of 1×6 poplar, 1 8-foot poplar 2×4, and 9 6-foot 5/8 inch dowels.
The frames were all to be made from the 3/4 inch poplar (other than the rails on the crib front). The first task was to cut all the various widths and lengths. Pieces were cut to length using the mitre saw and a stop block. It’s always better to use a stop instead of measuring and marking each time. I always try to double check that my measurements are allowing for the tenons on the ends of these frames. A common mistake is to cut off members of a frame at the visible dimension, even if you are the person who made the design.
With all of the pieces cut to size, the next task was to set up for cutting dados and rabbets. A dado blade should be carefully set up to be in the centre of the 3/4 inch material. It’s best to run the piece through then rotate it and run it through again. By doing so, you completely centre the dado. All the pieces should fit together easily.
The rail pieces for the front, into which the bars get glued, are an inch thick (not 3/4). They are cut from 2×4 stock and only the ends get tenons. It would be possible to make these rails from 3/4 inch material, but that leaves too little material once the 5/8 inch hole is drilled for the dowels.
With all of these pieces cut and set out, it is then a good idea to set up the router table and ease the edges of every piece. It’s important that there are no sharp edges on the crib and this is so much easier to do before any of the crib is assembled.
After all the corners have been done, it’s also a good idea to give the pieces a bit of a sanding. The faces with dados in them will not be easy to sand once the panels are assembled:
All of that can then be set aside. It took me an hour or two to cut all of these pieces. It would have taken longer if I’d not spent days thinking about and hours working out the details.
The 1/4 inch panels can be cut. It’s important to remember while doing this that you need to cut them so they fit in the frames. And once they’re cut, dry fit the pieces. You won’t regret spending the extra time if it turns out you needed to cut a 1/16th of an inch off something. I personally hate cutting wood that’s covered with glue.
Prior to anything else, the system for supporting the mattress needs to be started. I decided there would be 4-inch slots, 7/8ths of an inch wide, opposite each other to hold up pieces of poplar which would support the mattress. One set of slots would be for the high mattress position, the other set for the lower. These need to be carefully marked out so they all match. Then a 7/8 Forstner bit can do most of the work, and a jigsaw can get rid of the rest. I found it necessary to use a small drum sander inside the cut-out to get it completely smooth. Then I used a roundover bit in the router to ease the edges.
And then we’re ready for assembly. I began with the back panel. I used polyurethane glue but wood glue is perfectly fine. Polyurethane glue expands and fills any sloppiness of your joints. My joints were not bad but there was some variation in the thickness of the poplar, which threw off the thickness of the grooves and tongues and tenons a little. It’s important to remember that if you have a continuous 30-inch glue joint, it doesn’t need to be perfect to work perfectly well:
That said, cleaning the foamed-out polyurethane glue the next day is not a pleasant task. But once I was done, I assembled the end panels of the crib. While that was drying, I cut all the dowels to length and drilled the holes in the front rails. I started by marking the centre and then spacing the holes two and three-quarters on centre. That works out to having a two and one-eighth inch gap between the bars.
I must admit, I cheated a little with the design of this crib. I knew there might be some aggravation trying to get everything to line up top and bottom. While I had a fixed measurement for the front of the crib, I planned having a filler piece underneath the bottom rail because I couldn’t be one-hundred percent certain I would drill the holes for the dowels the exact right depth.
In fact, I planned the whole thing for straightforward building. The dados in the vertical supports for the end panels continue down to the floor and needed to be filled. This is not really the most acceptable thing to do if you plan on staining or some other natural finish. But the crib was to be painted.
Assembling the rails with the dowels to make up the front of the crib was a little different from everything else. Since I didn’t want to have to worry about making sure the bars were square to the rails, I glued the three panels together first. I used the rails for the front as spacers to hold the crib square while the glue dried. This was all done with the crib upside-down on the floor. That proved to be the easiest way to line up the parts.
Once that glue was dry, I glued together the front bar-assembly of the crib with the rails inserted in the dados of the end panels.
That is, I used the glued-up three sides of the crib to hold the rails square to the bars while the glue set. I needed to apply clamping force to hold the rails onto the dowels, so it was not a good idea to try to glue the entire front of the crib at once. Rather, I let the rail and bar assembly glue set and then glued the entire thing into the crib. Once again, I used polyurethane glue. These dowels are fairly consistent, but there is a bit of variation in diameter.
There was less glue to clean up than I expected. And there was also very little sanding to do, since I had made a point of sanding all the pieces before assembling them. So I could then turn my attention to making the parts to support the mattress.
I cut two pieces of wood long enough to have an inch sticking out each support slot in opposite ends of the crib. I marked these pieces just at where they reached the inside of end panels of the crib. I then cut notches large enough for pieces of poplar to drop in. This makes it impossible for the supports to be knocked out but also makes it easy to relocate them.
The piece of mdf that holds the mattress up has two finger-holes in it to make it easy to remove. There are also two cross-supports in the middle of the span of the main support, and these should be screwed in place if they ever seem likely to fall. These would be the only screws in the entire build.
All parts complete, the crib gets a few coats of paint. When the paint is fully dry, and the crib is completely assembled, it’s completely ready as a safe and pleasant place for a new baby:
This plan is for a wooden crib that meets all current safety standards. It has two mattress heights and is made using frame-and-panel construction for three sides, with bars on the front. There is no complex joinery, nor is there any specialty hardware required to build it. The design is straightforward, however it would make a good base for those who would like to add detail.
Suggested materials for this project are poplar and mdf. However, other woods are equally suitable. Once assembled, this crib will be a safe and comfortable place for a very long time.