Table Saws

The powerhouse in many cabinet­making and joinery workshops, the table saw is one of the most useful woodworking machines. It enables you to make precision cuts, either ripping timber to width along the grain or crosscutting to length. Accurate mitre cuts are easy to make with a sliding fence or carriage, while you can also achieve compound by tilting the blade. Large-dimension or panel saws are designed to handle full-size sheet materials, creating a very clean cut. A table saw produces a cleaner cut than a band saw and, fitted with the right TCT blade, can produce a cut almost as smooth as that made by a plane.

Machine Basics

A table saw is mounted on a steel cabinet, which houses the motor. An adjustable rip fence is mounted on the fixed table to the right of the blade. The sliding table on the left allows you to carry out precise crosscutting. The blade is mounted on a rise-and-fall arbor for adjusting the height of the blade above the table. For bevel cutting, the arbor enables you to tilt the blade up to 45 degrees in relation to the table.

Motor and Controls

Budget table saws may be equipped with brush motors. They are less powerful and noisier than induction motors, which are built to run for longer periods. Induction motors are generally fitted to heavier, more professional machines. These are often available as three-phase or single-phase. Motor rating is from about 1,000-2,000 w on small machines, while heavier saws may be 3,000 w or more. Activated by a simple on/off button or switch with a large, easy-to-reach emergency stop button. Separate power isolator switches are normal on professional saws. On a cabinet saw, the motor is supported on cast-iron trunnions.

Table

A heavy, cast-iron table provides greater rigidity and less vibration than one made from steel or extruded aluminium. On some machines a groove in the table accepts a basic mitre fence for accurate crosscutting. The mitre angle required is read off the protractor scale and the fence locked with a thumbscrew. A removable insert surrounds the blade and gives support to the material being sawn. You remove this from the table to provide access for changing the blade. On some machines the insert is hardwood, so can be replaced easily as it wears.

Ripsawing Timber

The rip fence must lock firmly to the front bar for accurate ripsawing. You adjust the cutting width by releasing and sliding the fence across. A fine adjuster built into the handle enables you to tweak the width setting if necessary. You should be able to reduce the effective length of the fence by sliding it back from the saw blade when cutting solid timber. On sheet materials, slide the fence past the blade to support the edge of the material.

Crosscutting Timber

A simple sliding mitre fence should fit snugly into its slot in the table. Too much play will cause inaccurate cuts. For more precise crosscutting and mitres, some saws are fitted with sliding tables, which can be locked in place for ripsawing. A holdfast ensures that timber is secure and will not move while passing through the blade. A hinged stop is normally fitted to the crosscutting fence, which has a graduated scale. You simply slide the stop along the rail to the measurement required and hold the timber against it while cutting. Indexing pins for the rail at 90 degrees (and often 45 degrees) enable you to make accurate repeat cuts without having to check the angle each time.

Blade

Blade diameters range from 203 mm (8 in) on small hobby machines up to 406 mm (16 in) on industrial saws. A 254 mm (10 in) table saw is capable of a cutting depth of about 76 mm (3 in) at 90 degrees, so it can do most of the work required in a small workshop with great accuracy. Tilted to 45 degrees, depth of cut is reduced, however.

Most table saws are fitted with TCT blades, which should only be re-sharpened by a saw doctor. Patterns vary from simple positive-hook teeth to trapezoidal, triple-chip designs for cutting plywood. The number of teeth per blade varies from a few as 16 for coarse ripping up to 100 or more for extremely fine finishing cuts in veneered boards. For general-purpose ripping and crosscutting in timber and sheet materials, a medium blade with about 48 teeth is suitable.

Behind the blade, a riving knife prevents timber from closing up and binding as it passes through the saw. An adjustable crown guard is fitted to this guard or to a pillar bolted at one corner of the table. If you remove the crown guard, never use the machine without making a jig of some sort to enclose the teeth. Hand wheels on the front of the machine enable you to raise and lower the blade and to tilt it from 90 to 45 degrees. For clean cutting you should adjust the blade so that teeth are protruding just above the timber.

Sliding Carriage

Many mid-size and bigger table saws can be fitted with a sliding carriage, bolted on as an extra. The table may be extruded aluminium or cast iron and will support bigger panels and longer lengths of timber than a smaller sliding table. A sliding carriage will add considerably to the footprint of the machine, however.

Scoring Blades

A large panel saw is generally fitted with a scoring blade, about 102 mm (4 in) in diameter. Located in front of the main saw blade, it provides a cleaner cut on sheet materials that would normally chip underneath, such as veneered or melamine-faced boards. The blade is raised so that the teeth pre-cut the material just above the table surface, in line with the main blade behind. On some table saws it may be necessary to reduce the size of the main saw blade in order to accommodate a scoring blade as well.

Bench-top Saws

If space in the workshop is really tight, you can mount a compact, portable saw on the bench top and store it out of the way when not needed. Instead of cast iron, the table is cast aluminium, while the body is heavy-duty moulded plastic, making the machine light enough to be used outdoors or even loaded into a car.

Blade diameter is generally 254 mm (10 in), making the saw capable of cutting 76 mm 3 in) timber. Motors are rated from about 1,600 w upwards. Although primarily a ripsaw, small-scale crosscutting and mitre cutting are also possible.

Site Saws

A basic saw bench, the site, or contractor’s, saw is mainly used for ripping timber with the grain. The table is normally galvanized steel to prevent rust and steel legs make it reasonably portable. Some even come with a built-in folding stand and wheels.

Hybrid Saws

With much sturdier build quality than a site saw, a hybrid saw is mounted on legs so is less enclosed than a normal cabinet saw and more compact. An optional mobile base makes it easy to move around in a small workshop. A moving, cast-iron table is built in, although sliding carriages are optional. This table normally has slots either side of the blade for a mitre fence. A substantial rip fence is standard, often with a fine adjuster. Auxiliary side tables may be steel, rather than cast iron.

Word Discription :

Crosscutting Sawing across the direction of the grain.

Crown guard Adjustable steel or plastic safety cover above the saw blade.

Kerr Width of cut produced by the blade teeth. Kickback When a work piece is ejected from a machine towards the operator by a rotating cutter or blade.

Ripsawing (ripping) Cutting parallel to the grain of the timber.

Riving knife A curved steel plate fixed behind the blade to prevent timber closing up and pinching as it passes through. Slightly less than kerf width but wider than blade thickness.

Set Saw teeth are alternately bent slightly to one side of the blade, then the other. The resulting cut (kerf) is wider than the blade itself.

TCT Tungsten-carbide tipped

Trunnion A casting on which the band saw table is mounted, enabling it to tilt. Usually incorporates a protractor scale to set the angle accurately.

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