Many do-it-yourselfers who have accumulated a set of basic hand tools and many small portable power tools want to further broaden their capabilities with stationary power tools, but are uncertain how to begin.

It's important to choose carefully because stationary power tools such as radial-arm saws, table saws, drill presses, belt and disc sanders and lathes are expensive and require a sizable amount of workshop space.

To further complicate matters, the tool shopper will find various combination tools such as the Shopsmith, which can be used as a table saw, lathe, sander and drill press and requires a smaller storage space than the separate stationary tools.

An experience with power tools convinces me that a radial-arm saw, also called a radial saw, is a wise first choice among stationary tools. A 10-inch saw -- measured by the diameter of the blade -- will handle most sawing jobs including the cutting of wood up to three inches thick. A first-rate radial saw can be bought for $300 to $400.

But a radial saw is much more than a saw. In the hands of a skilled operator who has the correct accessories, the tool can perform dozens of high-precision woodworking operations. The radial saw can become a sander, shaper, horizontal drill, router, planer, grinder, rotating wire brush, buffer and more.

The basic advantage of a radial saw over a table saw is that the wood remains in a stationary position during many of the sawing operations, including crosscutting and mitering. This is possible because the saw blade and motor are suspended from a rigid "radial arm" that spans the width of the work table. The blade and motor assembly are pulled along the arm and into the workpiece, a method that gives high visibility of the work and permits extremely accurate cutting if the saw is properly adjusted.

The radial arm that gives the saw its name can be raised or lowered and swung to the right or left for sawing at precise angles.

The motor and blade assembly are also adjustable and the blade, which in crosscutting moves parellel to the arm, can be turned so that it is at right angles to the arm. This is the position for ripping (sawing lengthwise with the grain of wood) and in this operation the blade is locked in a stationary position and the wood is pushed into the blade in the same manner as with a table saw.

The blade-motor assembly can also be turned so that the blade is horizontal in relation to the saw table instead of vertical.

The wide variety of possible positions, combined with an equally wide variety of accessories, gives the radial saw its versatility.

Every radial-saw owner should aquire at least three blades, each of which costs less than $10. These include a combination blade for routine crosscutting and ripping; a fine-tooth blade for cutting plywood, panel and other very thin material; and a hollow-ground planer blade. The last gives an extremely smooth cut and will stay sharp longer if it is used only for cutting when the smoothness is important, such as in furniture making.

Special carbide-tipped blades are available that also give extremely smooth cuts and will stay sharp much longer than ordinary steel blades, but the special blades are expensive (about $50) and are an unnecessary luxury for occasional users. When a steel blade becomes dull, a few dollars will get it resharpened.

Accessories for a radial saw should gererally be bought only as they are needed, but most saw owners will quickly find a need for these:

DADO BLADE. Dados or rabbets -- grooves in wood that strengthen joints and improve the appearance of many projects -- can be cut with an ordinary saw blade, but multiple passes or cuts are required. A dado blade can be set up to make a wide cut in one pass, speeding the work and generally doing it more accurately. There are two types of dado blades: One is a set of cutters stacked to reach the desired width; the other cuts different widths by angled rotation on a special hub. The stacking type takes more time to set up but usually costs less and, I believe, is a bit more accurate.

KEY CHUCK. An add-on key chuck, similar to the chuck that holds the bits in a drill, can be screwed onto the motor shaft to convert the saw for sanding, drilling and similar operations.

DRUM SANDER. A small sanding drum, used with a key chuck, is extremely useful because it can quickly smooth curved wood.

A new radial saw should came with an instruction booklet, but getting full value from the tool generally requires more than thorough study.

Sears has an excellent "Radial Saw Book," sold in the tool departments of its stores or by mail for $5.99. This plastic-covered, spiral-bound book will lie flat on a workbench for easy reference and has chapters on other power tools as well as full coverage of the radial saw.

Another fine book is "Getting the Most Out of Your Radial Saw," published by Rockwell International. This hard-cover volume can be bought at Rockwell tool dealers or by mail for $6 from Rockwell International, Suite 295, 1755 Lynnfield Road, Memphis, Tennessee 38138.