Aluminum has many things going for it. Its inexpensive, easy to find in your local home
improvement store, and easy to work with. Its strong, lightweight, and perhaps best of
all, it doesnt rust like steel does.
Like other metals, it does oxidize, but not enough to cause us any grief. This is very important
for those of us living in high humidity area with non-air conditioned work shops.
Aluminum Stock: a Variety of Shapes and Sizes
The fact that aluminum stock comes in so many shapes and sizes means that your work is likely to
be halfway done when you approach building a woodworking jig.
It can be found in U-channel, flat in a variety of thicknesses, or angled. Thin sheets can be
cut with tin snips (I prefer Weiss straight-cut aviation snips; I used to use Craftsman snips
when they were guaranteed by the Sears Craftsman warrantee. I guess they lost confidence in their
For thicker stock, use a hack saw and clean it up with a file or sandpaper. If you use your
table saw or circular saw, use a carbide tipped saw blade and wear polycarbonate safety glasses.
Jig Hardware: Carriage Bolts
Youll find yourself using a multitude of carriage bolts. Keep a stock of them at your work bench.
There are many sizes available; 5/16 inch and 1/4 inch are my favorites.
Youre not limited to conventional nuts, either. At many times, the jig lends itself better
to a knob or wing nut. Be sure to keep a supply of washers on hand as well.
Inserts and T-Nuts
Inserts and T-nuts also have their place in the world of jig building. So what are they?
Inserts are brilliant in the right setting. They are double threaded and look a bit like a
hollow bolt with no head. The threads on the outside are coarse because their job is to dig
into the hole youve drilled into the jig.
The interior threads hold the bolt. The tighter you crank the bolt down, the tighter
the insert bites in. Inserts dont do well in plywood.
How about those T-nuts? These fill the gap when youre working with plywood.
probably seen these before; They look like a nut with a large flanged head. Around the edge of
the flange are triangular metal teeth that bite into the surface of the jig.
Using a Knob with a Carriage Bolt
Theres a mind-boggling variety of knobs out there and theyre truly a carpenters
friend. They work really well on adjustable jigs. I usually buy mine on-line at
Rockler Woodworking and Hardware.
Here are a few I like to keep my work bench stocked with:
Studded Knobs - Studded knobs are actually knobs with the bolt already
attached to the knob. This works well with either T-nuts or inserts.
Captured Knobs - Perhaps the simplest of all, the captured knob has threads
inside the knob body to accept the carriage bolt coming through from the opposite
side of your jig.
Ratchet Knobs - Ratchet knob fulfill a very specific purpose when other
types of knobs are impractical: in tight corners when trying to make a complete turn
just leaves you with skinned knuckles and talking dirty. They come in both captured
and studded versions.
Through Knobs - There are times when the thickness of the jig (and perhaps
what youre attaching it to) varies with your woodworking project. In this case, none
of the aforementioned knobs work well. Enter the through knob. Its like a captured
knob with the threaded core wide open at the top so the bolt can extend through it.