Popular Woodworking 2002-08 № 129, страница 46

The tall spindle on a shaper allows it to be used with taller cutters, such as crown moulding cutters. Even with this monstrous stile-and-rail cutter installed, you can see how much spindle is still available.

Shaping Tight Contours

The small size of a router table and router bits can also be a tremendous advantage when shaping curved stock. Although both the router table and the shaper excel at shaping curved moulding, legs and other details, shaping tight contours is where the router table outperforms the shaper. Because of the small cutting diameter, router bits will shape curved edges of tight contours where the large diameter of a shaper cutterhead simply can't reach. In fact, the cutting diameter of many router bits is no greater than the shaper's spindle diameter alone.

Inside Corners

Many furniture details include sharp, distinctive inside corners at the intersection of profiles. And because both shapers and routers leave an inside corner rounded, the shaped detail must be carved by hand to be completed. But compare the small-diameter guide bearings to the large guide bearings on a shaper and you'll see that you'll do far less handwork if you shape the intersection with a router.

That's because the small diameter of the guide bearings on router bits allows the cutting edges to reach deeper into the corner and shape more of the profile.

Comparing the Cutting Geometry

Have you ever noticed that router bits sometimes have a tendency to burn or tear out the surface of the stock? As a general rule, shapers will cut smoother than a router table with less machining defects. And although there are several factors that contribute to surface quality when machining (such as the hardness of the wood, the type of grain and feed rate), the geometry of the cutterhead or bit plays a major role. Because of the large diameter of shaper cutterheads, manufacturers have more room to design the cutting geometry for the best performance. Specifically, the rake angle of the cutting edge dramatically affects the smoothness of the surface. The rake angle is created by

the face of the cutter as it intersects an imaginary line that starts at the center of the cutter and intersects the tip of the cutter. Although there isn't one perfect angle that works for all species of wood, a rake angle of approximately 30°, found on most shaper cutterheads, works extremely well.

However, because of their small diameter, there isn't room on the body of a router bit. As a result, when compared to shaper cut-terheads, many router bits cut with more of a scraping action. Besides the surface quality, a key indicator of the cutting geometry is the chips that are produced. While shaper cutterheads produce light, fluffy shavings similar to a hand plane, router bits produce chips and dust. That's why, when all other factors are equal, I'll choose to use my shaper over the router table.

Cost Comparison

For most of us, price is an issue whenever we consider a new tool. In this category, the router table is the winner, hands down. Although in recent years shapers have become more affordable, the machine's cutters can be expensive. And remember, it's the cutters or bits that give these machines their versatility.

Although a combination blade

works well on the table saw for a variety of cuts, each cut you make on a router table or shaper requires a router bit or cutters for that specific purpose.

Making a Choice

Clearly, there is no winner in the shaper vs. router contest. Although the tools are very similar, the router table and shaper each have distinct characteristics that give them advantages over the other. That's why I have both in my own shop. But if you're just starting out, I suggest that you begin with a large router table equipped with a router of at least 3 hp.

By owning a router table, you'll have an extremely versatile tool. At the same time, you'll be learning to use a shaper because the techniques for using the two are nearly identical. Later on, if you want to make large mouldings or need production capacity, consider adding a shaper. PW

Editor's note: Coming in the December 2002 issue: The basics of how to safely use a shaper. And in the February 2003 issue, Lonnie Bird shows you how to build simple custom fences for your shaper that make many operations quick, accurate and safe. Also, look for a review of some of the popular smaller shapers in an upcoming issue.

One of the big advantages of router tables is that they can sneak into tight corners a shaper can't touch.The ogee profile on this piece will need to be finished up with a little carving, but this cut would be almost impossible on a shaper.

Another advantage of router tables is that you can cut directly above the bit, such as with this fluting shown here. Making this cut on a shaper requires a trickier setup.

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