79 - Slant Front Tool Cart, страница 9
claim tin is type cuts faster and leaves a cleaner edge than other bits. The makers of radial-ground bits say their bits last longer. In the end, I've found that there isn't a huge difference in speed or results. Both types will work just fine and give you clean, crisp cuts. Straight bits can also be specially ground for plunge cuts. To leam more, check out the box below. Cutting Length. After checking out the number of cutting flutes and shape of the grind, it pays to think about the cutting length of the bit. Here is one case where bigger isn't always better. To get the best results, choose a bit with as short of a cutting length as possible that will still do the job. Although it may seem like a longer bit can do more, the truth is, you rarely need the extra length. I've even had a problem being able to retract a long bit into the router enough to make a shallow cut. There's a second reason a short bit is better than a long bit. The farther away from the motor the edge is, the more likely it is to vibrate, leaving a less than perfect edge. Along with cutting length, you'll also need to consider shank size. A stout VV'-dia. shank can absorb more stress and is less likely to deflect during a cut than a ]/j" shank bit will. If your router can accomodate them, you'll find that Vz" shank bits don't cost much more and will give you better results in the long run. THREE BITS YOU HEED With all these features in mind, the last decision you'll need to make is choosing the right-size bits. Although straight bits come in a wide range of cutting diameters, I've found that three sizes handle most of the work in my shop. The most-used bit in my collection is a ]/>"-dm. bit with a cutting length of l'A", as shown in the photo below and on the bottom of the opposite page. 1 use it mainly for routing dadoes and grooves in plywood conduction. But the cutting length allows it to take on other tasks like mortises and cleaning up rough cut edges. The second bit to have is a V4"-dia. bit (upper photo at right). It works great for routing the grooves for drawer bottoms. Mounted in a table, this bit can do just about anything an expensive slot cutter can. A Plunge bit. These bits can cut stopped grooves by plunging straight into a workpiece. Look a Bit Closer: Is it Really a Plunge Bit? A Small Bit. Turn to an inexpensive W-dia. bit for routing slots and small grooves. A Big Bit. You'll find a dia. bit can take the place of a rabbeting bit and can easily rout wide dadoes. The final must-have bit is a ?A"-dia. one like you see in the photo above. Besides routing wide dadoes and grooves, this heavy-duty bit can be used with an edge guide or in the router table to take the place of a rabbeting bit. All straight bits can rout grooves, dadoes, and rabbets. But when it comes to stopped or plunge cuts, as shown in the photo at left, not all straight bits are created equal. For these jobs, you'll need to take a look at the end of the bit first. A plunge-cutting straight bit has V-shaped cutting edge ground into the end of the bit, like you see in the photo at right. This allows the bit to cut straight in and form a hole like a drill bit, as in the photo at left. Plunge-cutting flutes While most straight bits have cutting edges on the end (that's how they cut clean, flat bottoms in grooves and dadoes), there's usually a gap between the cutters, as shown in the bit on the bottom of the opposite page. This bit won't cut right at the center, which can be a problem during plunge cuts. |
