-Shaped to your grip
-Unique; no one will walk off with your cutter by mistake
-Feels nicer than plastic
-Showing up to work with a custom box cutter just makes you look cooler (no, really)
-Box cutter. For this instructable, it should be the folding kind. Also note that some types use a metal tension arm down the spine and have metal scales. I tried using this type before, but the problem is that they put a huge amount of stress on the scales, and wood scales will split. Please refer to the pictures for what type of cutter to use.
-Hardwood scraps. Two pieces slightly longer and thicker than your cutter. Softer wood like pine will work.
-toothpicks OR coat hanger. Used to pin the cutter together.
-Glue. Gorilla Glue was used. Something that will bond metal and wood.
-Wood finish. I prefer plain tung oil. Keep in mind that you'll have your grubby hands on this a lot.
-Rotary tool OR knife. A rotary tool with sanding discs makes shaping the wood much easier, but whittling your handle will also work.
-Drill with small bits
-Sandpaper of various grits
-Screwdriver with hex bits. Most box cutters use uncommon hex bits to hold everything together.
Step 1: Disassembly
Locate the screws holding the cutter together and carefully remove. There will usually be thee or four, along the spine.
Next, remove the screw that the blade pivots on. You will have to hold one side of the pivoting mechanism in place while loosening the other side. There will be one or two washers inside.
There might also be a metal bar near the blade pivot. This is what the blade hits when it is unfolded (the "blade stop").
Keep track of all the bits that come off. Set aside all the metal pieces for now.
Step 2: Duplicate the Scales
Next, place the inner metal piece over your tracings. Mark the screw holes, as well as the blade stop hole.
Take the tool of your choice and cut out your traced outlines. You don't need to be too precise yet, as long as the inner sides are flat.
Note how one scale is thicker down the back, to fill in the space under the blade. Remove material from the corresponding side, leaving a thicker spine and bottom. Refer to your plastic scales and blade assembly to see how much you need to take off. Make sure you remove enough that your blade can fit and unfold.
Drill the hole for the blade pivot. You want this to be a pretty snug fit. Note how there's a recessed area that the pivot screw sits in. You can either take down the thickness of the whole area as I did on the picture in the into step, or you can try to drill a countersink, as pictured below. This isn't as important as getting the centre hole correct; just ensure that the wood scales are thin enough here so that the two halves of the pivot screw can be fitted together.
Drill the screw holes with a drill bit slightly smaller than your toothpicks.
Step 3: Reassembly
You may choose to use coat hanger or other wire instead of toothpicks. It can make for a cool look, but I find that it creates a lot of difficulty in the shaping stage.
Slip your blade stay in place. If it's too short for the hole, don't worry. Just make sure that you centre it when you do the final gue-up. You can cover any surface holes with sawdust or wood filler afterwards.
Try out the mechanism and ensure the blade can open and close properly. You might have to fiddle with your wood scales quite a bit until they're the right shape. Once satisfied, take the whole thing apart again, apply some glue and reassemble.
Note that since we replaced the screws with toothpicks, we're relying on the glue to help hold the pieces together. However, the toothpicks are important in keeping everything aligned and acting as a solid, physical join.
Step 4: Shaping, Smoothing, and Finishing
Once you have the shape you want, start sanding it smooth. Increase grits gradually, going as fine as you want. I went all the way to 600, but that may have been overkill.
This is a great opportunity to customize your cutter using pyrography, for example. Another idea is to drill more holes and insert toothpicks to create an inlay pattern.
Apply the finish of your choice. Sand lightly between coats. Enjoy!