Pin hinges—the most rudimentary of all hinge mechanisms—are simply rods (made of wood or brass) inserted into the carcass and lid, which allow the lid to be opened. Pin hinges (also called pivot pins) are used mostly in contemporary boxes. They are often used in boxes in which traditional hinges will not work or in boxes where a traditional hinge method would detract from the box design.
Because pin hinges are made from brass rod or wood dowels, they are by far the cheapest hinge mechanism available. For instance, a 1’ long, 1/8” dia. brass rod can yield several pairs of hinge pins but costs less than $1 at most hobby shops. Hardwood dowels are even more inexpensive.
Although pin hinges will work on many box designs, I don’t recommend using them on boxes made of softwood unless the hole is reinforced.
The repeated pivoting action of the pin will wear down softwood, resulting in a sloppy mechanism. One reinforcement option is to line the pin hole with a brass tube.
This article is excerpted from Box-Making Basics by David M. Freedman.
PIN SIZE AND MATERIAL
What size pin you use and whether you use wood or brass pins will depend on the size of the box you are making.
For small boxes with lightweight lids, use at least a 3/32” brass rod or 1/8” dia. hardwood dowel. For medium-sized boxes, use 1/8” dia. brass rod or 3/16” dia. wood dowel, at minimum. For large boxes or medium-sized boxes with heavy lids, use 3/16” dia. brass rod (I don’t recommend using wood dowels here).
Brass and hardwood are easy to cut, sand, and polish. Regardless of whether you’re using brass or wood pin stock, round over the ends to make the pins slide into their holes easily.
CONFIGURATIONS
Pin hinges are typically used in two configurations: vertical and horizontal. Using a vertical pin is an easy way to make a swivel-lid box. Installing pins horizontally allows you to open a lid by lifting its front, as you would with traditional hinges (see the drawing below). Depending on the box design (and on your tastes), you can leave the pins visible, or you can conceal them.
The biggest advantage to leaving the pin ends visible is that installing the pins is easy. Simply drill holes through a carcass side and into the lid simultaneously, with the lid taped or wedged in position.
Glue the pin to the carcass, so that the pivoting action takes place in the lid. (To glue brass to wood, use epoxy or cyanoacrylate glue.) Then trim and sand the pin flush with the carcass.
When you don’t want the pin hinges to be prominent (or if you simply want to avoid trimming and sanding the brass flush), there are two ways to conceal them. The main difference between the two methods is when you drill the holes for the pins.
The first method is to use blind pins. To install blind pin hinges, you must drill holes partway through the carcass before assembly, and then drill mating holes in the lid. No glue is needed for this method because the pin floats in the holes after the box is assembled. The second method of concealing pin hinges is to use a wood plug. After assembling the box, drill through the box sides and into the lid. Again, no glue is needed because the pin will float in the hole. After inserting the pin, glue a dowel in the hole, then trim and sand it flush to the carcass.
Box with Horizontal Pin Hinges
This article is excerpted from Box-Making Basics by David M. Freedman.
INSTALLATION TIPS
The techniques for installing pin hinges vary, depending on the design of the box. Overall, it’s a fairly simple process, but there are a few general guidelines that you should keep in mind. The pin holes must be exactly 90° to the surfaces in which they’re drilled.
You need either a drill press or a 900 drill guide for this operation. In a rectangular box where the pins are installed horizontally, the carcase must be glued up square so that the two pins line up.
In a box with horizontal pin hinges, the back of the lid has to be rounded to allow the lid to open.
This is the case whether the lid is inset or whether it rests on the back. If the lid is rounded just enough and no more, it’ll provide its own stop. I don’t have any formula for this: You have to round a little and test the fit until the lid stops where you want it to.
This article is excerpted from Box-Making Basics by David M. Freedman. ©1997 The Taunton Press.
