All too often, as an enclosed curved cut is completed and the outer ring separates from the center, the two pieces actually shift. Because the bit is still in the divide and still spinning, one of the pieces— usually the outer ring—gets gouged. (The disk seldom takes the hit, because with a trammel the router is moored to it, and with a router-table setup, the disk is moored to the pivot.)
If the outside portion is scrap, this shifting and gouging isn't a problem. But if that's the piece you want, then you need to hold it in position in relation to the center. Here are some ways to do that.
One is to use sandpaper. You can usually do this when routing with a trammel. Fold a sheet in half, abrasive out. and bond it with double-sided carpet tape. Slide three or four pieces of this stuff between the workpiece and the work surface. Be sure it is positioned where it can keep both inside and outside areas from shifting.
Another is carpet tape. If you simply stick your workpiece to a
piece of scrap, you can cut through your work and leave the scrap to hold the pieces together. As a rule of diumb. this procedure will work well as long as the smallest piece is at least twice as wide as it is thick. The taller and thinner a piece is, the more likely it is to be torn loose from the tape and become a projectile.
On jobs where the piece being cut out is bigger than the router base, you can often get by very nicely by working carefully on a gripping surface such as one of the dense foams. Obviously, you don't want to cut into these surfaces, so cut halfway through and flip the work. A word of caution, here. Many of the foams are not dense enough to retain two pieces in the same plane. You may find that as you cut the pieces apart, they tilt toward each other.
On very large pieces, you can hold parts in the proper relationship by taking partial cuts and stopping periodically to tape a ripping or a straightedge across the cut. Fred uses 3M plastic packing tape. It is strong and sticks well to wood, yet it pulls off cleanly when the time comes.
Fred spent a lot of time routing this circular frame and certainty doesn't want it spoiled when it is finally cut free of the inner dish that's anchoring the trammel's pivot. As you can see, the final cut—breaking through!—is completed only partway around the frame. Here Fred's applying long strips of packing tape across the back. The tape will keep the frame from shifting; just as the cut is completed.
the workpiece—use clamps, double-sided carpet tape, hot-melt glue-then move the router over it. Yoaj can make through c uts with straight bits, or decorative cuts with groove-forming profile bits.
There are several good reasons for using templates in routing cunts I and circles.
• Multiples. You need to duplicate a curve or circle again and again. A trammel will do it. but it's often faster and easier to position a template than to work with a trammel
• Holes. Here you confront the difi-culty of holding a ccnnerpoint if you re cutting out the area where the point is. Once it is set, the template doesn't need the center point.
• Complex curves. A trammel is great for a constant arc, but what about undulating lines? You need multiple centerpoints, different radii. A lot of setup rime, and if you're cuttinggood stock, you don't have a margin foe error. But you can fiddle with a template, trimming and sanding that curve until it is just what you want Then you can duplicate it per/ctf§ with your router.
More details on making and using templates arc found in the chapter "Template-Guided Work." Suffice it to say here that you can use your various trammels and router-table pivots to produce the template, then use the template to guide the cut on the good stock.
Was this article helpful?
Wood finishing can be tricky and after spending hours on building your project you want to be sure that you get the best outcome possible. In The Complete Guide To Wood Finishing you will learn how to get beautiful, professional results no matter what your project is, even if you have never tried your hand at wood finishing before. You will learn about every step in the wood finishing process from a professional wood finisher with years of experience.