This kitchen cutting board makes perfect sense: It fits over your sink so you can quickly wash and chop fruits and veggies and toss the waste down the disposer. And it can double as a traditional countertop cutting board, giving you the best of both worlds.
This is a custom-built project in every sense. Very few sinks are exactly the same shape and size; you’ll need to make a template of your sink’s opening to create the shape of your cutting board. Making the cutting board takes about four hours and costs about $40. The work is easy; you can do it even if you’re a novice woodworker with minimal tools.
A butcher block is an assembly of wooden strips glued together face-to-face so the cutting surface is edge grain. Because edge grain is tighter and straighter than face grain, the cutting surface is more durable, and because gluing together many thin strips makes the cutting board extremely strong, it won’t warp or distort over time. Use waterproof glue to join the strips so that frequent washing with soap and water won’t destroy your work.
Maple is a good choice for the cutting board — it’s dense and durable, so your project will last a long time. Don’t use softwood; it won’t hold up to knife cuts. And avoid softer open-grain hardwoods, as their open grain structure can capture food particles and harbor bacteria. A local lumberyard can supply maple and machine it into 1x4 pieces or even rip the finished widths, saving you time and the need for a table saw.
Over-the-sink cutting boards tend to be larger than traditional countertop cutting boards. Mine ended up being 12 in. wide x 25 in. long x 1 in. thick, and that makes it a bit heavy. Consider the overall size when you design your cutting board. It’s best not to make the strips thicker than they are wide because too few strips will lead to a weak assembly. (I made the strips 3/4 in. thick.) Also, to maximize strength, don’t make the board thinner than 3/4 in., and to minimize weight, don’t make it thicker than 1 in.
Building this project is so easy that you could do it with just a table saw, a jigsaw, a belt sander, an orbital sander, a glue (paint) scraper and various lengths of bar clamps. Add a router with a 1/8-in.-radius roundover bit and a drum sander (if you own one or know someone who does) and you’ll be zooming along.
The best finish to use on any cutting board is pure mineral oil because it’s nontoxic and food-safe. It also makes the wood water-resistant, but not impervious to water, so applying a fresh coat every few months is a good idea.
Making the Template and Strips
Plan for the cutting board to cover one-half to two-thirds of your sink’s opening. Make a template of that portion of the opening (photo 1). Heavy poster board will work better than cardboard for more complex sink shapes since it is easier to cut accurately with scissors. You could also use 1/8-in.-thick hardboard and woodworking tools to make a stronger and stiffer template, but that will take more time and effort. After tracing the shape on the template material, carefully cut it out and make sure it fits perfectly in the opening.
To make a template of your sink’s opening, cut a piece of cardboard to partially cover the opening and tape it over the sink. Reach underneath and use a pencil to trace the shape.
Make the cutting board’s finished dimensions 1 in. wider and 2 in. longer than the template. This allows for a 1-in. lip on the three sides of the cutting board that rest over the sink. Divide the finished-width dimension by 3/4 to determine how many wood strips you need. Cut the strips 2 in. longer than the finished length; that allows enough extra to easily cut the assembled blank to its finished size.
Gluing up the Blank
Shop-made wooden blocks called cauls are used to hold the cutting board strips flush while the glue-joint clamps are applied. Make four cauls 1 in. x 1 in. x 2 in. longer than the cutting board’s finished width (photo 2). Make sure the cauls are square and flat. You could make the cauls 3/4 in. thick if necessary, but they will be a little harder to clamp down.
Make four wooden clamping cauls to keep the assembly flat when gluing the cutting board strips together. Cover the cauls with painter’s tape to keep glue from sticking to them.
It’s too difficult to glue and clamp together more than six strips at one time, so you’ll glue up the blank in stages (photo 3). Let the glue cure for 15 minutes; then remove the cauls. You may need to use a hammer to tap and release them. Wait 15 minutes more; then use a paint scraper to remove the partially dried beads of glue that ooze out of the joints. Leave the assembly clamped for at least 12 hours; then repeat the procedure, adding the second third of the strips, and then repeat again, adding the last third (photo 4). Use a belt or drum sander to sand the blank flat on both faces.
Glue together one-third of the cutting board strips. Lightly clamp the cauls over the strips. Add the assembly clamps; then apply more pressure to the caul clamps.
Complete the glue up with the rest of the cutting board strips. Make sure you apply enough glue to the joints.
Shaping the Blank and Finishing
Use the template to draw the shape of the cutting board onto the blank (photo 5). Cut out the shape and sand the sawn edges smooth; then round over the edges (photo 6). Rubber feet screwed to the underside of the board align and secure it in the sink’s opening. Attach the rubber feet (photo 7); then remove them and finish-sand the cutting board using an orbital sander.
Trace and enlarge the template shape on the cutting board blank. Use whatever tools are necessary to define the shape. (The shape of my sink is simple; yours may be more complex.)
Rout the edges using a 1/8-in.-radius roundover router bit. You can do this by hand with sandpaper if you don’t own a router.
Before you fasten the rubber feet to the underside of the cutting board, center the template and draw the sink-opening shape again. Align the feet on the ends and as far out to the sides as possible.
Apply a coat of Butcher Block Oil (photo 8). After it cures for a few days, reattach the rubber feet and add the door bumper cushions (photo 9) and the cutting board is ready for use.
Apply a coat of Butcher Block Oil (food-safe mineral oil), following the directions on the bottle. Even though it’s nontoxic, it is messy, so wearing gloves is a good idea.
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