68 - Our All-New Router Jig, страница 22
JIGS & ACCESSORIES W: Building your own shop jigs is a great way to put some extra cash in your pocket. And by using the right materials and hardware, you won't have to sacrifice performance or accuracy: e use jigs all the time in our shop. They make a task faster, more accurate, and safer. Some of these jigs are made "quick and dirty" — they're used once and then tossed out. So we don't worry too much about what they're made out of. But if a jig is going to see frequent and heavy-duty use, it's best to take the time to carefully select the materials and hardware you use. There are all kinds of materials and literally hundreds of pieces of hardware that could be used. But for our jigs, there's really only a handful we turn to time and time again. Some are specialized enough that it's best Shop Jigs Materials & Hardware * Plywood. A mainstay for long-lasting jigs, high-quality plywood (like the Baltic birch shown above) provides flatness and stability for fences (left) and bases (right). i Hardboard & MDF. Smooth and strong, hardboard (left) makes a fine, low-profile base or replaceable inserts. MDF (right) is an inexpensive way to build an entire jig. to order them as they're needed. But most of the materials and hardware detailed on the next few pages are things to keep on hand all the time. SHEET GOODS One of the first materials I consider for a jig is hardwood. I like it for the small parts of a jig — usually all I have to do is sift through the scrap bin to find just the right piece. But hardwood isn't always the best choice. There are three types of sheet goods I like to keep a constant supply of because one (or two) of them are used in just about every jig I make: plywood, hardboard, and medium-density fiberboard (MDF). Plywood - The advantage of plywood compared to solid wood is that it stays flatter and is more stable over time — an important consideration for the fence or base of jigs like the ones shown in photos A and B. In our shop, we typically build our jigs with hardwood plywood or, more often, Baltic birch plywood. They have more plies and fewer voids compared to construction-grade plywood. And their faces are harder and much smoother. So the jig is sure to last a long time. Hardboard - Another sheet good that sees a lot of use in our shop is a processed wood product — hardboard. It's made by mixing and heating wood fibers and synthetic resins. This mixture is then compressed into large, flat sheets that are stiff and strong. Plus, hardboard is inexpensive and it comes in uniform thicknesses (Vs" and WO- But make sure you don't settle for just any hardboard. For most jigs, you'll want to use tempered hardboard. It's smooth on both sides. Not like some hardboard that comes with one fuzzy, waffle-like face. Tempered hardboard is a great choice for the base of small jigs. That's because you get strength and stability without limiting the depth of your cut, like you see in photo C at the bottom of the page. In the same photo you'll also see a part of the jig that gets chewed up during use — the backing insert Since tempered hardboard is stiff and inexpensive, you can make a bunch of replaceable inserts for pennies—and you'll always have some on hand. Medium-Density Fiberboard -Another product that's similar to tempered hardboard is MDF. Like hardboard, MDF is smooth, stable, and inexpensive. Plus, it comes in thicker sizes. You can use it for fences, bases, or even an entire jig, like the shooting board you see in photo D at the lower left. One more thing to mention about MDF — it's heavy. Which can be an advantage when you're building a piece of shop equipment like a lathe stand (ShopNotes Issue No. 67). The extra weight provides stability and makes it virtually vibration-free. But you probably don't want to build a large jig out of MDF since it can be difficult to handle. PLASTiOS Like wood-based sheet goods, there's another material that can make a jig safer, eliminate problems of wood movement, or simply make it more accurate — plastic. Polycarbonate/Acrylic - Two common plastics that I use on jigs are polycarbonates (like Lexan) and acrylic (Plexiglas). What these plastics do is provide a "window" to what's happening with the jig. Acrylic is more commonly available and it's what I turn to most often — except when there's a 22 ShopNotes No. 68 |
