Popular Woodworking 2002-08 № 129, страница 45

Another significant difference between the two machines is that the spindle of a shaper is much longer than the shank of even the tallest router bits. The extra length will enable you to use tall cutterheads for shaping wide, flat profiles such as ogee crown mouldings for furniture and architectural woodwork. In comparison, router bits are vertically challenged by the relatively short length of router-bit shanks. Even so, the largest routers don't have the heavy-duty bearings and horsepower to support and drive large bits through heavy cuts.

Comparing Horsepower

Horsepower obviously has a direct relationship on the size of cut a machine can produce. A typical ^V" spindle shaper comes equipped with a 3-horsepower motor. Although it's true that large routers also have motors rated at 3 hp or perhaps even greater, they're still no match for the same size shaper. Why? The difference lies in the type of motor. Large stationary woodworking machines such as shapers use induction motors that are designed to produce their rated horsepower

continually under heavy loads. They will push large cutterheads through dense stock all day long.

However, most portable power tools such as routers use universal motors that will produce their rated horsepower only for short bursts before they overheat and shut down. Fortunately, today's routers are designed with thermal overload protectors that cut power to the motor before it burns out. If you've ever run large cove cutters or panel-raising bits in your router table, you've probably stalled the motor a few times from overworking it.

Although you can avoid overheating your router by taking multiple light passes until you've reached the full depth of the profile, an average shaper can shape most profiles such as a raised panel in one pass. In contrast, a router table will typically require three to five passes to shape a panel edge, depending on the density or hardness of the wood. When shaping long runs of mouldings or a number of raised panels for kitchen cabinet doors, the time saved with the shaper is significant. And in fact, you'll even notice a difference when shaping

Even the smallest shapers (those with a 1¹/2 horsepower motor) are powerful enough to raise a panel in one pass. Most routers would need to perform this operation in three or more passes.

One of the advantages of the shaper is that its motor can run in reverse.This allows you to adapt to wood where the grain runs in a different direction. It also helps with wide, thick or odd-shaped stock.

smaller profiles as well; the shaper powers through any cut more efficiently and smoothly.

With its large spindle and plenty of raw power, the shaper is clearly the best choice for production runs and large, heavy cuts. But a table-mounted router has several distinct advantages over the shaper, too. Let's take a look at some of these advantages.

Versatility

Although a table-mounted router is no match for a shaper in size and horsepower, it makes up for it in versatility. For example, a table-mounted router can be used for plunge cuts when shaping flutes and grooves, whereas shapers can't. That's because shapers use a spindle nut to secure the cut-terhead but routers use a collet to secure the bit. In fact, this feature allows manufacturers to produce a whole array of router bits that cut on the end, such as core-box and straight bits.

However, as I mentioned earlier, size is also another important difference between the two machines. Although the smaller scale of a router and router bits is sometimes its greatest weakness, many times it's also its greatest strength. The small size of

router bits and their guide bearings enable you to make a variety of cuts that are difficult or impossible to make with a shaper. Let's look at a few.

Shaping Small Stock

Because of its smaller size, the router table is by far the best tool for safely and effectively shaping small stock. And with the enormous variety of router bits available, diminutive details that are difficult to produce with a shaper are created easily with the router table. If you flip through the pages of any router-bit catalog you'll see dozens of scaled-down profiles that simply are not available for the spindle shaper.

Additionally, the small diameter of router bits allows you to use a much smaller fence opening, which greatly decreases the chance of a short work-piece dropping into the bit and being spoiled.

Remember: Whenever the workpiece is small, it's important to follow all the manufacturer's safety precautions and use the appropriate jigs to distance your hands from the spinning bit. The jig can be as simple as clamping the work to a backup board attached to the miter gauge.

44 I Popular Woodworking August 2002