So, you’ve got a beautiful new slab door—that’s a flat door without any pre-cut holes or hinges. Hanging it might seem like a task for a seasoned carpenter, but with a bit of patience and the right approach, you can mortise those hinges yourself for a perfect, flush fit. Mortising is simply the process of cutting a shallow recess so the hinge sits perfectly flat with the door and frame. It makes the door swing smoothly and gives it that clean, professional look. Don’t worry; we’ll walk through this together step-by-step in a way that’s totally manageable for a dedicated DIYer.
First, gather your friends. You’ll need a sharp pencil, a combination square, a sharp utility knife, a sharp chisel (about 1 inch wide is perfect), a hammer, and a router with a straight bit if you have one (though we can do it without). Safety glasses are non-negotiable—you’ll be dealing with sharp tools and flying wood chips. Start by holding your hinge against the door edge where you want it. Typically, the top hinge is about seven inches from the top of the door, and the bottom one is about eleven inches from the bottom. Mark the top and bottom of the hinge leaf with your pencil. Then, use your combination square to extend those marks squarely across the edge of the door. This creates the boundaries for your mortise.Now, set the hinge itself right on those lines and trace its exact thickness. This is the most critical marking step. You want to know exactly how deep to chisel. A great trick is to score these lines with your utility knife, pressing down firmly. This cuts the wood fibers and gives you a super-clean edge to chisel against, preventing the wood from splintering beyond your line. For the depth, just lay the hinge flat on the door edge and mark a line along its side; that’s how deep your mortise needs to be. Usually, it’s just the thickness of the hinge leaf.If you’re using a router, you can set the depth and carefully clean out most of the waste inside your scored lines, staying well away from the final edges. But the trusty chisel method works wonderfully. Start by making a series of shallow cuts, about an eighth of an inch deep, inside the mortise area, going across the grain. Then, with your chisel held bevel-side down for control, gently tap to peel out these small chunks of wood. Work slowly from the center toward your scored edges. Once you’ve removed the bulk of the waste, you can carefully pare down to your final depth, using the flat side of the chisel to smooth the bottom of the mortise. The goal is a flat, even recess.With the mortise cut, it’s time for a test fit. Place the hinge into the recess. It should sit flush with the door edge, not proud or too deep. If it’s a little tight, you can pare away a sliver more wood. Once it fits perfectly, hold the hinge in place and mark the center of each screw hole with your pencil. Pre-drill small pilot holes for the screws—this prevents the wood, especially on hardwoods, from splitting. Now you can screw the hinge firmly into place. Repeat the entire process for the second hinge on the door.Remember, the door frame needs matching mortises too! The process is identical. The key to success is taking your time with the layout and the scoring. Rushing the markings or trying to chisel out too much wood at once is where mistakes happen. Go slow, let the sharp tools do the work, and make small adjustments. When you finally hang that door and it swings open and closed seamlessly, flush against the frame, you’ll feel an incredible sense of accomplishment. You didn’t just hang a door; you mastered a fundamental woodworking skill that will serve you for countless future projects. Now, step back and admire your handiwork—you’ve earned it
October 11, 2025
