RADIAL ARM SAWS
A radial arm saw uses a circular saw, but instead of feeding the material into the blade, the item to be cut remains stationary and the saw travels through the cut, pulled across the track on the radial arm.
The cutting portion of the blade is rotating away from the operator. The cut is made by pulling the saw across the material against the operator. This puts the pressure on the al downward against the cutting platform and a fence at the rear of the platform. It pushes away from the operator.
Because the radial arm saw virtually cuts backwards, it develops its own pull through the cut so that the operator may wind up holding the saw back rather than pulling it through the cut.
For ripping longer pieces of wood, the saw can be pivoted 90 degrees and locked into place on the radial arm. The material is fed in on the upward moving side of the blade to prevent the blade from pulling the wood through and binding.
If the wood binds, the saw will “kick” it back toward the operator. To prevent this, radial arm saws are equipped with an anti-kickback device that allows the wood to move into the saw but locks into it if the direction is reversed, driving it down onto the table and preventing operator injury.
Ripping is limited by the length of the arm, which is usually 24″ or less. On a 24″ saw, one portion of the material being ripped must be less than 24″ to fit between the blade and the fence at the rear of the platform.
Cross cuts are also limited by the length of the arm. A 24″ arm would allow for a 12-3/4″ cross cut, as the center of the saw blade will not travel from one extreme of the arm to the other. A radial-arm saw is particularly effective for mitering, and is usually equipped with stop mechanisms at 30° and 45° angles, plus a locking device that allows setting of any angle for the arm.
The saw can also be adjusted for bevel and compound cuts.
Accessories can be added to the radial arm saw to perform dadoing, sanding, shaping, sabre sawing, surfacing, jointing, horizontal boring and over-arm routing.
Band saws will cut much thicker material than table saws or radial saws and are particularly useful for making irregular cuts in thick material They will cut stock over 6″ thick and have band (or loop like) blades in various strengths and widths for different cutting purposes.
For example, a 1/8″ wide blade will have a minimum cutting radius of 1/4″, while at the other extreme, a 3/4″ blade will have a minimum cutting radius of 5-7/16″. Skip-tooth blades are used for cutting aluminum, magnesium, plastics and wood.
A band saw is recommended when you need a tool that will handle heavy-duty cutting work on a constant basis. Cutting tables will tilt to 45°, giving a variable cut for normal cutting operations.
Sanding attachments and sanding loops are available for sanding on irregular or curved surfaces.
Scroll saws consist of a small thin blade activated by a far-reaching arm that permits handling wide material. Power is provided by up-and-down motion of small blade at more than 1,000 cutting strokes per minute. It will cut designs in plywood, light metal and plastic.
Features include a surface which tilts in either direction and magnetized saw blade that moves rapidly through material to be cut. Saw is relatively safe, inexpensive and lightweight.
A table saw has a flat cutting surface with the circular saw blade extending up through a slot. Motor and drive mechanisms are located under the table surface.
The size of the table determines the size of the material that can be cut. Small units are designed for light ripping and cross cutting while large units can accommodate 5′ x 8′ sheets of plywood.
Rip fence capacity is another criterion for determining saw capacity. The fence is mounted on the table and adjusts to guide the material being cut. The maximum distance between the saw blade and the rip fence determines the maximum cut that can be made.
If you are a beginner, remember that the material being cut must be fed into the side of the blade traveling downward. This automatically drives the material against the table, especially if the blade should bind. If fed in from the upward motion side, the material would be forced over the top of the blade and pulled forward by the teeth. Most models feature safety blade guards that ensure material is fed from the proper direction.
There are also saws that allow the material to be positioned for cutting before elevating the blade, eliminating the need to slide the material over the blade.
The blade is elevated with the push of a handle making possible chop-type cuts on cross cuts, miters and bevels.
|Most common cause of loss of control of a jointer-planer-and resultant injury to the operator’s hands-is “kickback.” Kickback is the unexpected simultaneous grabbing and throwing of the wood at high speed toward the in-feed table. This danger does exist, but a study of operating practices and techniques associated with the jointer-planer shows that it can be as safe as it is versatile. The study was made by the Power Tool Institute Inc. and the Department of Health, Education and Welfare’s Bureau of Product Safety.|
|The Occupational Safety and Health Administration (OSHA) has standards that apply to use of these and other products that might injure the user. Information on OSHA regulations is in the Electrical Supplies chapter of this handbook. The following are safety practices that will help avoid kickback while using the jointer-planer.|
|1. Always use adequate hold down push blocks when jointing materials narrower than 3″ or planing material thinner than 3″.|
|2. Never edge joint-work pieces that are less than 1/4″ thick, 3/4″ wide or 12″ long.|
|3. Never surface plane wood less than 5/8″thick, 3/4″wide or 12″ long, or wider than the length of the cutter head knives.|
|4. Do not take too deep a cut: No greater than 1/32″ per pass in wood with knots or 1/16″ in clear wood.|
|5. Always keep knives sharp.|
|6. Set up machine properly. Knives must be uniformly, exactly in line with the surface of the rear (outfeed) table or a few 1,000ths of an inch higher.|
|7. Use the machine only for those jobs for which it was intended. Never attempt to perform an unfamiliar operation without adequate study and safeguards.|
|8. Never back up the work piece.|
|9. Adequately support the work piece at all times.|
Combining the functions of circular saw and jointer, a saw-jointer performs as well as or better than either of the single units and its cost is lower than the combined price of the two units.
JOINTERS OR JOINTER-PLANERS
The jointer or jointer-planer is used to “true-up,” size or smooth wood in width (edge) or thickness (surface)-doing the job of a hand plane faster and better. The jointer can also be used to perform special operations such as tapering, beveling and grooving. (See the above special safety rules that apply to using the jointer-planer.)
Wood is removed with knives or cutters that are fitted into a cylindrical head, which revolves at 3,500 to 4,500 rpm. Good-quality jointers feature head with three or four knives; low quality tools have only two knives in each head.
A 6″ wide cutting table holds material which is pushed across the table and over the cutter cylinder. A control knob enables the fence to be tilted for angle cuts. Tilts up to 45× either way are normal. Although any jointer can cause harm if misused, rotating knives are protected by a cutterhead guard.
A lathe consists of a bed or metal track for positioning wood to be carved. Wood is fitted into two heads-one a permanent head which holds one end and provides driving power, the other a movable head which is adjustable to the length of the wood.
Tool rest is adjusted for carving at different positions. Rest has a lock position which permits user to secure it for permanent carving in one spot.
Lathes can be run at speeds ranging from 500 to 3,700 rpm.
Skilled workers soon learn to adjust lathe to proper speed. Carving tool is then held against tool rest at the proper position and angle for the carving operation. As wood spins, surplus amounts are removed and the desired design is accomplished.
A bench grinder is considered a stationary tool because it is usually bolted to a bench in a workshop. It is used for sharpening all tools, as well as for polishing.
Tool consists of a motor powering one or two grinding wheels. In many tools, the motor is located between grinding wheels.
A drill press consists of base and a column rising upward to a head holding the motor and drill. A radial arm holds a worktable, which adjusts vertically. The drill press shapes, carves, sands, grinds, buffs and polishes with appropriate accessories.
A feed handle enables the user to direct drill chuck up and down to proper location.
With a few attachments and the use of multiple speeds, a drill press can be converted for metalwork, routing, grooving, milling or shaping.
On radial drill presses, the head will rotate 360 degrees around the column and can drill at an angle or horizontally.
The combination tool costs less than individual stationary power tools, takes up less space and is more convenient.
Check your state and local codes before starting any project. Follow all safety precautions. Information in this document has been furnished by the North American Retail Hardware Association (NRHA) and associated contributors. Every effort has been made to ensure accuracy and safety. Neither NRHA, any contributor nor the retailer can be held responsible for damages or injuries resulting from the use of the information in this document.