Circular saw

A circular saw is a machine for cutting separation of workpieces. With their cutting jobs are carried out on various materials such as wood, metal, plastics, building materials or natural stone. They can be distinguished according to the nature and purpose, with the largest number is used on saws in the field of separating wood and metal.

In general, there are disparities among saws for artisanal and industrial use, because they have different machines sometimes considerably in their dimensions and their function.

• 2.1 Stationary Saws
• 2.2 riving knife
• 2.3 Circular Saw Blades
• 2.4 Drive
• 2.5 Circular Saws

Species

Stationary Saws

Stationary saws are used in workshops and on construction sites.

• Table Saw
• Underfloor circular saw
• Flush-
• Sliding Table Saw
• Multi-blade circular saw
• Edging circular saw
• Veneer saw
• Rolltischsäge
• Panel
• Pendulum circular saw
• Under chop saw table saw
• Tilting circular saw
• Cold Circular Saw
• Stone saw
• Longitudinal circular saw
• Under table saw chop saw

Circular saws for inner hole separating

For circular saws for inner hole separation is the cutting edge on the inside of a hole in the center of the circular saw blade, which has the advantage that the blade ( outside) can be clamped tighter, when sawing less " flutters " or vibrates, causing more precise cuts with thinner blades are possible and less noise is produced. With such saws are at a minimum possible cutting width of 0.3 mm (with correspondingly little cutting waste ), cut semiconductor ingots into wafers in the semiconductor industry ( microelectronics, photovoltaics and micro system technology ) with otherwise unreachable precision or geometric planarity.

Construction

Stationary Saws

On the machine column of table saw machine, the work table is attached. The latter has a through-opening for the circular saw blade. Inside the machine units for driving the saw, as well as the mechanism for adjusting the height and inclination of the circular saw blade are accommodated. Pivoting and Höhenverstellbewegung via a hand wheel or an electric motor. The angle adjustment allows precise sawing of angles between 0 ° and 45 ° ( also often from -1.5 ° to 46.5 °). Some manufacturers offer machines since about 2006, sliding table saws with a swivel range of 92 ° (2x 46 °). Depending on the manufacturer and used pivot mechanism, the max. Saw blade when panning from 46 ° to -46 ° vary. On one side of the machine table is the rip fence. It allows the workpiece sections to width, wherein the desired level is preset to a scale. At Saws a rolling table is mounted on the opposite side of the machine. This refers to the angle-adjustable crosscut stop. Workpieces are placed on the table and roll past the circular saw blade. Here, too, desired dimensions and angles are preset to appropriate scales. The cross stop can be removed for reasons of space.

The angular accuracy for 90 ° longitudinal sections, which is necessary especially for furniture can be checked with the " 5-cut method": a square board is trimmed five times at right angles, where the board is rotated after each cut by 90 °. The last section is cut then from a thin strip of the square whose edges are to be exactly parallel ideally. Thus, the angle between the lateral and stop cutting blade can be checked, the result is an angular deviation measured in lateral deviation per cut length.

Riving knife

The most important and most effective safety device on the circular saw is the riving knife. It is located behind the saw blade. He keeps the kerf open and prevent the workpiece or small parts are detected from the ascending blade and thrown in the direction of the user at hand saws a setback as well as injuries of the cutting edge due to unclean leadership. The keeping open of the kerf of the saw blade after the splitting wedge designed to prevent under -voltage standing timber behind the blade back to the contracted section. Therefore, the riving knife must also have a certain width of the kerf width [ CRC ] and the thickness of the base blade [ Sbb ] is dependent on the blade. " Riving knife thickness = ( CRC Sbb ) divided by two ": In order to calculate an appropriate benchmark, the formula is valid. In addition, the riving knife can prevent reaching into the ascending blade. For this, the appropriate riving knife must be set correctly: He must be as close to the saw blade; depending on the workpieces, with saw type, the distance to the teeth must not exceed eight or ten millimeters, with circular saws than 5 millimeters; its upper edge can be between the height of the tooth root and two millimeters below the cutting circle flight. So even hidden saw cuts are possible. The thickness of the riving knife must be between kerf width and the thickness of the saw blade blank. For different saw blade thicknesses thick gap wedges are accordingly required. Sawing without a riving knife is only allowed for specific activities such as Einsetzsägeschnitte. Then the riving knife must be mounted immediately.

Circular saw blades

In circular saw blades distinction is made between single-piece circular saw blades and composite circular saw blades.

One-piece circular saw blades are made from one piece of steel strip from which they are punched out, to then be provided with the desired tooth shape. Since they are only suitable for cross and rip cuts in solid wood and material-related wear out faster, they lose more and more important.

Composite circular saw blades are made of a metal body, are soldered onto the carbide or polycrystalline diamond. Since the cutting edges are always wider than the metal support body, a cabinet of the teeth is not necessary.

The use of the blade depends on the cutting geometry of the sawtooth. This includes, for example, the tooth form, or the number of the teeth ( tooth pitch ). The optimal selection and determination of a saw blade, especially for industrial use is very important, it depends on the different variables such as material to be cut in wood also whether longitudinally or transversely cut that wood moisture is present, speed of the saw ( cutting speed), feed speed, engine power, to be achieved cutting quality, of life and of course the price.

The tooth profile is divided into:

• Flat tooth. Rip cuts in soft and hard wood
• Alternating teeth: Also referred to as universal blade, as it is suitable for cross - as well as longitudinal sections.
• Hohlzahn: For veneered surfaces, since the erosion tear-free work guaranteed. Care must be taken to the cutting speed.
• Trapezoidal tooth: Ensures a good result in lacquered and coated surfaces.
• Trapezoid flat tooth combination: Suitable for plastic and 10 mm as well as panels, as Spanausräumung, splinter-free cutting are possible.
• Roof rack flat tooth combination: Suitable for plastic-coated flat pressed particle board.

Drive

The drive of the circular saw shaft by V-belts, toothed or flat belts on different sized pulleys. In connection with pole-changing three-phase motors such different speeds and thus different average speeds. Many boaters are directly driven by particularly flat electric motors ( see first figure ). In the drive configuration is to pay attention to the speed to be achieved, which in turn, results in function of the size of the saw blade (diameter) of the average speed. The ideal, economical and best cutting speed depends on the material to be cut. Many machine manufacturers offer optional for their machines also frequency-controlled motors. This makes it possible to adjust the blade speed steplessly ( often in the range of 2,000 to 6,000 s -1). This allows on the one hand, a material-dependent optimal cutting speed ( eg for plastic) and, secondly, a very fast and convenient adjustment of the frequency of rotation of the saw blade, even while the machine is turned on.

Circular saws

The structure of the portable circular saws differs from the stationary circular saws in adaptation to their purpose. While stationary circular saws, the work piece is passed over the work table with a circular saw, the tool is guided over the work piece. Compared with the work table of a stationary circular saw, the base plate of the portable circular saw is relatively small. The saw blade is covered to the top, to avoid injury from flying around and chips. The lower part of the saw blade is covered with a movable protection which is only pushed back by this during penetration into the workpiece. An exception here is the track saw: Here, the base plate is movably mounted so that the blade does not protrude into the lower zero position of the base plate. The cut, the blade is forced out through the base plate downwards.

Diving circular saw

Saw blade and riving knife above

Swung the blade and riving knife down

To save space, the blade often sits directly on the shaft of the drive. The machine with the press of two buttons on the handle is activated (The power switch is operated by the index finger, the safety switch with the thumb ). This is to prevent that the engine is unintentionally activated. Through a pipe, the chips are to the side and blown or sucked backwards. Since the handle is to the left of the saw blade, the operation of a portable circular saw for left-handers is usually uncomfortable.

For long sections can be attached to the work piece as a guide, a wooden stick, a guide bar or a spirit level to ensure a straight cut. Some models have the saw table grooves in order to lead them exactly along a guide rail can.

For the purpose of accident prevention and the cut quality, it is recommended that before the correct depth of cut set (workpiece thickness rd. 2 mm). Also, it is possible on a piece of corrugated board for cutting the thin plate, for example on the ground, whereby said rest surface and damage to the cutting edge can be avoided.

Safety note

Fast running tools involve risks and should only be operated by competent persons. Compliance with all safety regulations and the use of the given safety devices ( eg leaf cover, riving knife, push stick, feeding aids ) is absolutely necessary. Boaters cause an A -weighted sound power levels of up to 110 dB. Working with hearing protection and other security techniques is therefore absolutely necessary. When dealing with moving machine gloves can not be worn, as they get into the machines and can mithineinziehen hand.

To cut to length waste and firewood, jigsaws are better suited as table saws, the risk of injury is significantly reduced.

There are also modern boaters stop the saw blade immediately when a body part of the worker comes into contact therewith.