68 - Our All-New Router Jig, страница 23
JIGS & ACCESSORIES
chance it could get hit by a bit, blade, or workpiece. Since acrylic is brittle, it can easily shatter. So for the amber-colored guard you see in photo E at right, polycarbonate is a better choice. It serves as a constant reminder to keep my hands away from the saw blade when making the cut — yet still be able to see the cut.
In photo F, you can see how a small piece of Plexiglas can be used as an accurate indicator simply by scoring a "hairline" in the surface.
Phenolic - Another plastic product I really like is phenolic. Like hardboard, phenolic is made in a two-step process. First, layers of paper are coated with a resin. Then the paper and resin are squeezed in a heated press to a uniform thickness.
In the end, the phenolic comes out very hard and smooth. And it doesn't absorb moisture, so it won't shrink or swell. So you can use it for runners on the base of jigs. Plus, it's incredibly strong and stiff. That makes it a perfect choice as a mounting plate for a router, like you see in photo G at right.
Unfortunately, phenolic isn't perfect For one thing it can be rather expensive—and difficult to find. I typically order it through the mail from one of the many woodworking catalogs available (refer to the sources listed in the margin on page 35).
Laminate - A lot of times you don't need an expensive piece of thick phenolic to get a hard, smooth surface. When that's the case, you can turn to plastic laminate.
▲ Aluminum. Whether it's just a piece of flat stock for a stop block (left) or a piece of angle for the body of a shop-made tool like the scratch stock (right), aluminum is easy to use and work with.
The process for making laminate is similar to that for phenolic, but laminate is much thinner. The advantage of this is you can attach it to any surface. On the platen for the edge sander shown in photo H, the laminate was glued to a piece of hard-board and then screwed in place. It provides an easily replaceable, long-wearing surface.
Another advantage is laminate is much more common. You can find it at just about any home center in a variety of sizes and colors. And since it's quite inexpensive, it's a good idea to keep a supply on hand.
UHMW - Whenever I need an almost friction-free surface, I like to use a material called ultra-high molecular weight (UHMW) plastic. The thing that makes UHMW so slick is its self-lubricating property. Parts slide along like they're on ice. But it's not as fragile as ice — it's a tough, dense material that is very stable so it won't bind (or get sloppy) with changes in humidity.
This makes it ideal for use as a runner in the miter slot of a table saw (see photo I at right). It even comes in thin, self-adhesive strips that work great as a facing for an auxiliary fence, as in photo J.
Like phenolic, you won't find UHMW at the local home center or hardware store. But it is available from a number of mail-order sources.
One last material I've been turning to more often these days when building a jig is metal. And I'm not talking about screws and bolts (there's more on them later).
Aluminum - The metal of choice for jigs is aluminum — for a number of reasons.
First, ifs strong. So your jig will last. And it's lightweight, so it won't make a jig that's too heavy or hard to handle. Aluminum is also inexpensive — it
A Polycarbonate & Acrylic. Virtually unbreakable, polycarbonate is best for see-through guards (left) while inexpensive acrylic makes a great hairline indicator (right).
A Phenolic & Laminate. A phenolic plate is the perfect choice for mounting a router (left). And laminate makes a long-wearing and easily replaceable platen for an edge sander (right).
A UHMW. Jigs slide easily when they're guided by a runner (left) made from UHMW. And a workpiece will slide just as easily by adding a thin strip of UHMW (right) to an auxiliary fence.
won't cost a lot to use it in your jigs. Finally, aluminum is easy to work with. It cuts easily with a hacksaw. Cleaning up the edges is just a matter of a little file work and sanding.
But what's really nice is aluminum comes in a variety of shapes and styles. You can buy flat stock, angle, and U-channel. So finding just the right piece you need for a jig is easy.
A simple piece of flat stock was used to make a strong, lightweight stop on the miter gauge fence shown in photo K at left. And since it's so easy to work with, we used it as the base for a shop-made scratch stock (see photo L). Finally, to see how we used aluminum as part of our easy-to-use mortising machine, refer to page 12 for details.