How to Use a Door Hinge Jig for Accurate Hinge Mortises

A door hinge jig uses a hinge-shaped template and a router fitted with a guide bushing to cut a precise, flush mortise for a butt hinge, without you having to lay out and chisel the recess by hand. This guide focuses on getting the depth and alignment right for a single accurate mortise, whether you’re hanging a new door or fitting a replacement hinge into an existing jamb.

What a Door Hinge Jig Actually Does

Jigs like the Milescraft Hingemate or a shop-bought router template work by pairing a hinge-leaf-shaped cutout with a guide bushing threaded into your router’s base. The bushing rides against the template’s edges while the bit cuts inside it, and because the bushing has a larger outside diameter than the bit, the template opening is intentionally sized differently than the actual hinge leaf to compensate for that offset. This is why swapping router bits or bushings without checking the manufacturer’s compatibility chart throws off the whole cut.

Setting Router Depth for a Flush Mortise

Measure the hinge leaf’s thickness with calipers rather than trusting the box, since residential hinges typically run between 1/16 and 5/32 inch depending on weight and finish. Set your router’s depth stop to that exact measurement, then make a test cut in scrap material and set the hinge leaf into it. It should sit perfectly flush with the surrounding wood, not proud or recessed; a leaf sitting proud will bind the door on closing, while one recessed too deep leaves a visible gap and strains the screws.

Aligning the Template on the Door and Jamb

Most jigs include a registration fence or lip that hooks over the door’s edge, setting the mortise’s setback automatically, typically 3/16 inch from the face for standard residential hinges. Clamp the template securely on both sides before routing; a jig that shifts even 1/16 inch mid-cut ruins the mortise and often means starting over on a new section of the door edge. When cutting the matching mortise on the jamb, use the same jig flipped or repositioned so both mortises align exactly when the door is hung, since even a small mismatch causes binding or an uneven reveal. For deeper cuts you can also reference our guide on cutting door hinge mortises to a 1/8-inch depth.

Finishing Corners and Test-Fitting the Hinge

Most router templates cut a rounded corner radius that matches standard hinge corners exactly, so the hinge drops in without further work. If your hinges have square corners instead, you’ll need to square off the rounded corners left by the router bit with a sharp chisel. Always dry-fit the hinge before driving any screws, checking that it sits flush and the knuckle barrel lines up cleanly between the door and jamb mortises.

Frequently Asked Questions

What size guide bushing do I need for a hinge jig?

It depends on the specific template, but most residential hinge jigs are designed around a 5/8-inch outside diameter bushing paired with a 3/8-inch or 1/2-inch straight bit. Always check the jig’s included instructions, since using the wrong bushing-to-bit combination changes the mortise’s finished size.

Can I use the same jig on both the door and the jamb?

Yes, most hinge jigs are designed to register on both the door edge and the jamb face using the same template, which is what keeps the two mortises aligned when the door is finally hung.

What if my mortise comes out too deep?

A slightly deep mortise can be shimmed back to flush with thin cardboard or a veneer shim cut to the hinge leaf’s shape and placed underneath it. If it’s significantly too deep, it’s usually faster to fill the mortise with wood filler or a glued-in wood patch and re-rout at the correct depth.