Tool School: Radial Arm Saws
If, for some unknown reason, you had to pick only one stationary power tool for your workshop, a radial arm saw would be the wise choice. No other stationary power tool can perform as many chores. Woodworking consists of six basic cuts; crosscutting, bevel crosscutting, ripping, bevel ripping, mitering and bevel mitering. The radial arm saw will make all of these cuts efficiently and precisely. With attachments and accessories the radial arm saw can also be used as a boring machine, router, sander (either drum or disk) and buffer/polisher. It can also do jointing and shaping chores, as well as make dadoes.
Radial arm saws are available in several different sizes, and the size refers to the size of blade the saw will accept. Common sizes include a 10- or 12-inch model, with the 10-inch model the most popular choice for most home workshops. Larger, 14-, 16- and 18-inch sizes are also available for heavy-duty commercial work. The size of the blade determines the possible cutting-depth of the saw. A 10-inch saw blade cuts to a 3-inch depth. Most quality saws today have automatic blade brakes to slow and then quickly stop the saw once the motor has been turned off.
The primary use for radial arm saws is crosscutting. The stock is positioned in place and the saw is drawn across the stock, providing very precise cutting.
The reason radial arm saws are so versatile is because of their ability to configure for different cuts. A radial arm saw consists of a motor on a rotating arm positioned over a table top with a fence located near the back of the table top. The arm can be lowered or raised as desired. The radial or travel arm supports a sliding saw/motor. The arm rotates around the support column. Indexes precisely position the motor at 90 degrees to the saw fence, or 45 degrees in either direction. The column can also be locked in place at any degree in between. Regardless of whether set at 90 or some other degree marking, the primary use is for crosscutting. Radial arm saws also allow for precise cutting because the upper surface of the wood is facing you, and your marks are easily seen.
The radial arm saw can also be used to rip stock to width. In this case, the blade is stationary and the stock is pushed into the blade.
The new Craftsman Professional 10-inch radial arm saw has Laser Trac, a module mounted adjacent to the blade on the saw’s spindle. This provides a laser line that gives a clear indication of blade travel for ripping or crosscutting operations. A centrifugal switch, built inside the module, triggers the laser’s operation once the blade reaches 1,500 rpm. The new Craftsman saw also features Control Cut, an exclusive mechanism powered by a separate motor with a steel cable connected to the cutting head. This feature allows the user to control the saw’s feed rate and helps ensure accurate repetitive cuts at a consistent speed. The cutting head advances at a user-determined rate and automatically returns when the saw’s handle is released. Control Cut eliminates surge cuts, improves precision and cut quality.
The saw/motor unit is held by a carriage with a yoke. The yoke allows the saw/motor to be swiveled 360 degrees on the carriage, while still allowing the carriage to travel the length of the support arm. With the saw blade turned 90 degrees to the arm, or parallel to the saw fence, ripping operations can be done. By setting the blade slightly off 90 degrees, coving cuts can be made with the blade, creating rounded cuts.
The motor and blade can also be turned in a second yoke, allowing the spindle to face towards the table top or at any angle and be locked in place. This provides a position for any number of accessories.
What to Look for
In addition to today’s “bells and whistles,” several features are important in radial arm saws. First are the controls. The controls should be easy to access and grouped according to logical progression. The on-off switch should be easily within reach and large, so you don’t fumble turning the machine off. The switch should also be lockable, or have a removable key. The miter- and bevel-cut stops should be adjustable to make precise 45- and 90-degree bevel and miter cuts. The scales should be large and easy-to-read. The new Craftsman model has bright yellow scales for high visibility. The saw table should be a comfortable working height, usually 36 inches and should be large enough to securely support stock. The fence should be easily adjustable and the table top smooth. The motor should be large enough to handle heavy-duty chores. A 1 1/2-horsepower motor is a good choice with a 10-inch saw. The motor should have a double spindle. After removing the saw blade, accessories can be attached to the opposite spindle end and used for any number of chores.
Radial arm saws are equipped with safety guards, and the guard should be transparent to see through it clearly. The guard should move easily out of the way as it touches the work piece, but should drop down immediately once past the work piece. The saw is also equipped with anti-kickback fingers, which should be adjustable and work easily. Last, check the accessories available from the manufacturer, as well as those available from other manufacturers.
Radial arm saws come with a saw blade, normally a carbide-tipped, 40-tooth, combination blade that is good for all-around use. To do much ripping, a ripping blade, which has fewer but larger teeth — normally 24 — is the best choice, especially if ripping hardwoods. Extremely fine cabinet work may require a special hollow ground, planer or fine-cut blade and these normally have 80 teeth.
Dadoes, tenons, grooves, lap joints and other wide cuts are made using a dado blade or dado set. The cuts can be made with the saw in either the crosscut or rip position. Dado sets consist of two outside blades, with chipper blades between. Removing or adding the chippers creates the different dado widths. Adjustable dado heads create the different width cuts by turning a dial. Because of the volume of wood and the force exerted when making these wide cuts, it’s extremely important that the stock be held solidly in place and the anti-kickback fingers are working properly. Special guards are required to use dado cutter heads.
A drill chuck, fitted to the outfeed spindle end of the saw, can turn the radial arm saw into a drill press. Or a drum sander can be fitted into the chuck for precise contour sanding. A router bit or drill press planer can also be inserted in the chuck for a number of other chores.
A radial arm saw mounted on lockable casters can be moved to any position needed. The one accessory that can provide better and easier use is an outfeed stock support. Trying to crosscut long stock is hard and dangerous because the wood tips up when cut, but a support makes the chore easier. By the same token, when ripping long stock, the outfeed end tends to drop down, creating irregular cuts and a possibly dangerous situation. One of the best tactics with radial arm saws is to build a 6-foot outfeed table on each side of the existing table. Although these take space, they provide support during both operations.
If the radial arm saw provides extreme versatility in its many configurations, the drawback to that feature is more can go wrong with the alignment. It’s extremely important to ensure the machine is properly set and aligned correctly to make precise cuts and wood joints. The machine should also be regularly checked to make sure it doesn’t get out of alignment.