Installing hinges by hand is quick and easy if you know a few tricks for cutting mortises.
If I have a half-dozen or so boxes I might set up my small trim
router with a straight bit to install hinges (more on that another time). But if I only
have a couple boxes, it's just as quick to install the hinges by chopping mortises.
The trick to getting a lid to sit on the base properly is chopping the mortise to the correct depth. If you cut too deep the lid will be raised at the front, to shallow and it will stand proud on the hinge side. So, how do you get a consistent depth for your mortise? It's actually not that hard.
I start installing hinges by marking out where I want to put each hinge, then folding the hinge over the side of the box and tracing the outline of one "wing" of the hinge. Then I take a sharp chisel and make a cut on the inside of the line I just marked.
It's better to make your mortise a hair small, then trim it to exact fit when you're done.
Don't forget to make your first cut across the grain,
otherwise you can easily split the wood. This is an important step
because these cuts (along the line marking your hinge wing) determine
the edges of your mortise, so make sure and follow your line carefully.
Once you have all three sides cut along your pencil lines you are ready to start cutting your mortise. Hold your chisel at an angle and make many cross-grain cuts across the mortise. The trick here is to keep the cuts even, so use steady taps of the mallet. This is how you end up with a clean and consistent mortise.
Go straight across the mortise at the same angle. Once you've chopped your full mortise clean it up with the chisel held horizontally.
This will give you a flat and even bottom to your mortise.
Your goal is to get the hinge to sit flush in the mortise (this info is for butt hinges, other hinges may need to be mortised differently). If you go too deep you can always glue a shim under the hinge.
Cut one mortise for each hinge and attach it in place. It's best to pre-drill for the screw holes.
Once you cut the mortise for the first wing of the hinge it's time to layout the second side. What you want to watch here is the gap between the box top and base. The gap needs to be the same size as the barrel of the hinge.
I use a shim between the top and base to hold the hinge where I want it, then I mark the second wing of the hinge.
The shim insures that the gap is consistent so the top won't be on at an angle. After marking the spot, chop the remaining mortises the same way you did the first.
If you make a mistake when drilling for the screw holes fill the holes with a sliver of scrap and re-drill. After practicing installing hinges a few times, you should find that cutting mortises to install hinges is pretty straight-forward.
You can use the same technique for cutting mortises and tenons, or other types of mortises. You will need to make several passes to get the proper depth, but making small angled cuts helps insure consistent depth no matter what type of mortise you are chopping.