A good rule of thumb is that the door thickness should be less than three times the width of the hinge.
Out-of-square cases and doors with twist can create installation and functional problems. Make a final check of your case and doors and resolve any problems before you begin.
The door reveals can be adjusted after the hinges have been fitted, but the door should be close to the size of the case opening before you begin.
Cut mortises in the case before you glue up so that you will have more room to work.
Orient the pin-leaves so that the pins are pointing up. (The pin leaf mounts to the case on the bottom and the door on the top.) Note that L-Hinges are either right or left handed and reversing them will orient the pins downward, making it difficult to install the washers when the doors are fitted.
Starting with the case, determine the placement of the hinges. You may find it helpful to lay the hinges on a drawing of the case to finalize the placement.
The pin location determines how far the door will open. To prevent binding, the top and bottom pins should be in line with one another.
Cutting the Mortises
Hold each hinge in place and trace its perimeter with a fine knife. Route out the primary waste, leaving the layout lines. Use a chisel to pare to your layout lines. Check the fit of your hinge leaf. It should fit snugly. If it is too tight don’t force it in as you could damage the wood or get the hinge stuck. If you cut the mortises too deep, try using paper shims to pad the hinges up.
Installing the Screws
Using a #43 bit, drill the shank clearance to a depth of 1/16” below the bottom of the mortise. Using a #52 bit, drill the pilot hole to a depth of 5/16” below the bottom of the mortise.
To prevent damage to screws and hinges, your screw driver should be no wider than the screw head and should fit snugly in the slot. Use a dab of wax on the screw threads to ease installation. Don’t over-tighten the screws. Brass screws are soft and can be damaged or broken.
Screw the case leaves into place. Once they are installed, you should not have to remove the case leaves.
Screw the door leaves into place to tap the holes, then remove the screws to hang the door.
Hanging the Door and Adjusting the Reveal
With the hinge washers off, hook the leaves together and slide the door onto the door leafs. Be careful not to rub hinge leaves together as they may scratch. Trial-close the door and make note of necessary changes. Slide the door off the hinges and adjust the door size as required. (If you remove material from the top or bottom edges of the door, then you may have to adjust the depth of the door mortise accordingly.) The aim is to keep the door square to the opening and to create just enough room to install the washers. (Washers are necessary to prevent the door from rubbing on the case or the leaves from rubbing against each other.) When you are satisfied with the reveals, install the washers and screw in the door hinges. Use the spare screws to replace any screws that may have been damaged during the fitting process. Any part of the hinge protruding from the case should be eased with sandpaper.