Knife hinges...

I've spent a little time ensuring the front doors were square and true to the carcase, this involved some judicious hand planing along the outside edges of the door frames where I had purposely left a fraction of an inch of extra wood. I'm preparing myself for the next step in the build sequence which is installation of the knife hinges. I typically use knife hinges in a cabinet such as this. Knife hinges are strong, fairly hidden, elegant looking, and traditionally used in smaller cabinets such as this jewelry armoire.The knife hinges come in pairs , one pair per door. Knife hinges are available in two formats. In this project, I've chosen to use straight knife hinges since the doors overlap the carcase. An L-type or offset knife hinge would have been used had the doors been rabbeted or recessed into the carcase edges instead. The straight knife hinge is by far the easiest of the three to install.

The installation consists of mortising hinge recesses in the base and top of the armoire, one per hinge. A complementary recess is mortised into the top or bottom corner of the door frame, again one per hinge. Accuracy is key with knife hinge installs. In the photo above you notice a small spacer behind the knife hinge. This spacer has been measured from the edge of the carcase to the leading edge of the hinge on the door itself. A good reason for using this spacer is that I want to leave a consistent reveal between the rear edge of the door and the carcase edge. In my case, I've decided to leave less than 1/32 inch. This 1/32 inch is combined with the thickness of the remaining wood after hinge is centered on the door. The spacer makes it easy to mark where the hinge should be installed. The other mark for the hinge is the width of the knife hinge itself, or 3/8 inch in this case. The same spacer is used on each of the corners of the carcase.

Hinge installs on the tops and bottoms of the door frames are fairly straightforward. The center of the door frame is used as a reference and the hinge mortise is equal on either side, in this case approximately 3/16 inch. As a precaution, I fit the doors back into the carcase and confirm the outline of the door part of the hinge using the base or top hinge for a reference. Another important consideration is to create each mortise in a straight line and parallel to the carcase or door frames. The depth of the mortise is the thickness of the knife hinge leaf. The hinge pin straddles the corner, however this can be adjusted later in the fitting of the doors by sliding the hinge in or out a fraction of an inch..

I mortise the hinge recesses using a set of bench chisels, and much prefer this method. This method also allows me to install the knife hinges after the carcase is assembled which results in a more accurate installation. If there was a time you ever needed to exercise patience in woodworking, this would definitely be it. Carving out the mortises is a somewhat slow , tedious process, but as you can see the results are very satisfying. You will need very sharp chisels if you use this process. I've completed four base and top hinge installs, next are the door frame mortises and hinge installs. Afterwards, I install the doors and adjust.

I'm anxiously awaiting the final installation of the doors, afterwards I can move on to working on the interior of the armoire. The interior drawer section involves more detailed work.