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 product).
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 on hand. 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 in various sizes 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. Youve 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.
I hope this overview of metal and hardware for woodworking jigs has been of some help whether you're a beginning woodworker or have years of experience under your tool belt. If you have more tips, add them to the comment section.
Kelly R. Smith is an Air Force veteran and was a commercial carpenter for 20 years before returning to night school at the University of Houston where he earned a Bachelors Degree in Computer Science. After working at NASA for a few years, he went on to develop software for the transportation, financial, and energy-trading industries. He has been writing, in one capacity or another, since he could hold a pencil. As a freelance writer now, he specializes in producing articles and blog content for a variety of clients. His personal blog is at I Can Fix Up My Home Blog where he muses on many different topics.