Installing Quadrant Hinges
without a Router
P. Michael Henderson
Some time back, I volunteered to do a tutorial on installing quadrant hinges on a box, such as a jewelry box, without using a router. I said the next time I built a box, I'd document the installation of the quadrant hinges in a tutorial. But I didn't have any plans to build a small box so it was looking like the tutorial would not occur for some time.
However, Scott Krallman of Post Falls, ID volunteered to ship me a box he made to use for the tutorial. When he made his offer, and I accepted, I didn't know what the box looked like. Then he sent me some pictures - see next.
What I discovered was that his box was a veneered box and the decorative edging was wenge. The difficulty with his veneer pattern is that if the hinges are not put on exactly right, the veneer will not line up and it'll be obvious that something's wrong. The problem with the wenge trim is that I'll have to cut through the wenge to install the hinges. Wenge is a hard wood that splits fairly easily. Not the easiest wood to work with. So installing the hinges is going to be a challenge, even more than usual when installing quadrant hinges.
Before I get into discussing how to install the hinges, let me talk a bit about how boxes are generally made - because the technique I use depends upon the box being made this way. Most boxes are made as a closed box first (a cube), and then the top is cut off of the cube. Doing it that way guarantees that the top is exactly the same size as the bottom of the box, and that the grain (or decoration) lines up.
When the box is built this way, the first step is to make sure the top is matched to the bottom, exactly the way it was cut off of the bottom. This means that the top will fit and the grain will match. It's possible that when you made the box, it may have been slightly out of square when you glued up. If you put the top on correctly, no one will ever notice. But if you reverse the top, you'll never get the top to fit correctly - and the grain will not line up.
When I received the box from Scott, I put the top on and rotated it to look at how the top fit to each side. I found that the veneer pattern would only line up on all the sides when the top was put on one way. So that's the way I'm going to orient the top to install the hinges. That's the orientation shown in the pictures above.
Scott also sent me the hinges. He chose Brusso hinges.
Brusso makes very high quality hinges, and charges a high price. These hinges run about $40-$50 for the set of two. Note that the support arms can be removed from the wings. That's not true of all quadrant hinges and will affect the way you install the hinges. When the process is different if the support arm is not removable, I'll try to remember to note it in the text.
Notice in one of the pictures above that there's a piece of blue painter's tape on the top and on the bottom. This marks the back of the top and bottom. You don't want to get confused and install the hinges in the wrong edge. The tape helps you remember which side you should be working on.
Before we get started, let me make some prefatory comments. Let me begin by naming the parts of the hinge. A standard hinge is made up of two "wings" (sometimes called "arms") connected by a "knuckle". The knuckle is made by bending parts of the wings and inserting a pin down the middle. A quadrant hinge has an additional part, the "support arm" or "stop" which keeps the wings from opening all the way back. People who call the wings "arms" usually call this part a "stop" to avoid confusion. I'll use "wings" and "support arm" in this tutorial. On some quadrant hinges the support arm is removable, and on some the support arm is not removable. A good quadrant hinge should have some thickness to the wings (for long term stability), but I've installed quite a few that had thin wings and they worked fine, at least while I had the box. The hinges with thinner wings are a LOT less expensive - for example, see these at Lee Valley (who sells quality merchandise). It's pretty hard to bite off $40-$50 for the hinges when the materials for the box may have been mostly cut-offs from your other work. I'd encourage you to try the less expensive hinges for all but your show quality boxes.
Installing hinges requires precision in your work, and as the work gets smaller, greater precision is required. Installing a pair of quadrant hinges on a box requires great precision if the top is to fit well. You can use a router to install these hinges but I've always done it by hand (with the help of a few power tools). I feel like I have better control using the techniques described here.
The major point of precision is in the location of the hinges. They need to be the same distance from the outside and back edges on both the bottom and the top so that the top will fit neatly on the bottom.
So let's get started. Begin by laying one of the hinges along one edge (the back corner) of the bottom or top. Here, I'm starting with the bottom. I have the hinge completely open and the other wing of the hinge flat against the back of the box. This will give me the proper front to back spacing as I inset the other hinge wing.
Using a knife, mark the front edge of the wing which is along the edge.
Incidentally, I use Japanese marking knives which are single bevel knives. This allows me to place the knife mark exactly against the front of the hinge wing.
If you're using a quadrant hinge with non-removable support arms, you first need to mark the approximate location of the hinge wing and cut out space for the part of the support arm that protrudes below the wing. This will allow you to place the wing flat on the edge. Since you can't bend the other wing all the way back, as I did here, use the flats (the cuts in the wing against the knuckle) of the wing you laid on the edge to align against the back of the box. That's not as easy as what I did here but it's not all that difficult either.
Next, we need to space the hinge wing exactly in the center of the side. Actually it doesn't have to be centered, but then you have to do all the other wings exactly the same. I find it easier to center the wing.
To center the wing, use a small combination square and adjust the scale so that you can place the square against the side of the box (inside and outside) and have the scale just touch the wing, without moving the wing. When you can do this, the wing is centered and you have a measurement that can be taken to the other wings to make sure they're exactly the same. Once you find this distance, make sure your combination square is locked down securely, and set the square aside. Make absolutely sure the scale does not move during the setting of the hinges (meaning don't drop the combination square:-).
This assumes that sides have the same thickness. If you find that one side is not the same thickness as the other, use the outside of the box as your reference surface.
Now, make a knife mark along the sides of the hinge wing. It's easier (and more accurate) to make the knife marks using the combination square rather than trying to hold the hinge in one place while you mark along the sides.
Marking the outside (pix above)
Marking the inside (pix above)
I have to hold everything AND take the picture so this looks a little strange. It looks normal when two hands are used to hold the combination square and the knife.
Next, we need to cut the front of the mortise in a curved shape to match the curve on the wing of the hinge. The leg of the wing is 5/16",
so the diameter of the "circle" at the end of the wing is going to be 5/16". I can use a 5/16" Forstner bit to cut that part of the mortise.
The hinge makers usually make their hinge wings some standard size, but you could encounter a hinge in some non-standard size, or in a metric size. To cut the front radius on those, I use a carving gouge. I'm a carver so I have a lot of carving gouges, but if you're not a carver, take your hinge to a dealer who sells carving gouges and choose a gouge with sweep that matches the curvature of the hinge wing. Use the gouge to lay in the front of the mortise.
If you recall, I used my knife to mark the front of the wing and the sides. If I was very precise, the knife marks for the sides will be 5/16" apart. I can take the 5/16" Forstner and position it so that it just touches the three lines (front and two sides).
As you can see, the Forstner bit fits exactly. Now, let's drill out the front of the mortise.
Note that I've placed a "stop" on my drill press table so that I can position (front to back) where the hole is drilled. I'll use this stop for drilling the front of the mortise in the other three wings (other side of the bottom and the two mortises in the top).
Now, how deep should I drill the hole? The wing is about 3/32" thick.
So when I drill the hole, I want to go just a bit deeper. Although I don't show the whole caliper, I'm using the caliper as a depth gauge and I drill the hole just a bit deeper than 3/32".
I next take the box to my workbench and use chisels to cut out the mortise for that leg of the wing. Since the wood is wenge, I need to be very careful to keep from breaking out the sides. I use my 1/8" chisel to excavate the center of of the mortise before I trim the sides with a 1/4" chisel. When I cut downward with the 1/4" chisel, the wood breaks to the center rather than to the sides.
There's another round corner on that wing of the hinge and I need to use the Forstner bit to cut that corner of the mortise round. I mark the far side and the front of that part of the wing, and take the box to the drill press to drill the hole.
Now, just excavate the mortise. Note that the next picture shows the mortise on the other side of the box. Sorry, I just didn't take pictures of this step on the first mortise I did.
And if I was careful and accurate, the hinge wing will fit right into the mortise. I run my finger over the top of the wing to see if it's flush with the top of the side. If not, I'll clean out the mortise a bit more. I'm satisfied when the wing is flush with the side. If you leave the wing proud of the side, there will be a gap between the top and the bottom. If you set the wing too deep, the back of the top and bottom will hit before the front is closed and there may be a gap in the front. If you have a gap in front but you can close it by pressing on the top, you may have set the wing too deep. You can take a piece of veneer and glue it into the mortise to raise the wing by 1/42" inch.
These same steps are done to cut all the mortises - two in the bottom of the box and two in the top of the box.
The tutorial continues here.