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Causes and Operator Prevention of
Kickback:
Kickback is a sudden reaction to a pinched, bound or misaligned rotating wheel. The wheel may stall and cause an uncontrolled machine to back out of the kerf toward the operator.
If an abrasive wheel or diamond wheel becomes twisted, canted or misaligned in the cut, the side of the wheel that is entering into the material can dig into the top surface of the material causing the wheel to climb out or kickback out of the kerf.
Abrasive wheels may also shatter under these conditions causing pieces or fragments to strike or impale the operator and bystanders. Kickback or shattered wheels are the result of tool misuse and/or incorrect operating procedures or conditions and can be avoided by taking proper precautions as given below:
Maintain a firm grip with both hands on the machine handles and position your body and arm to allow you to resist kickback forces. The operator can control kickback forces, if proper precautions are taken.
When wheel is binding, or when interrupting a cut for any reason, release the trigger and hold the machine motionless in the material until the wheel comes to a complete stop. Never attempt to remove the machine from the work while the wheel is in motion or kickback may occur. Investigate and take corrective action to eliminate the cause of wheel binding.
When restarting a machine in a workpiece, center the wheel in the kerf
and check that the sides of the wheel are not engaged into the material. If wheel is binding, it may walk up or kickback from the workpiece as the machine is restarted.
Wheel depth adjusting locking levers/nuts must be tight and secure before making a cut. If depth adjustment shifts while cutting, it may cause binding and kickback. Using the machine with an excessive depth of cut setting increases loading on the unit and susceptibility to twisting of the wheel in the kerf. It also increases the surface area of the wheel available for pinching under wheel twisting conditions or misalignment.
Use extra caution when making a “Pocket Cut” into existing walls or other blind areas. The protruding wheel may cut objects that can cause kickback.
Some dust created by power sanding, sawing, grinding, drilling, and other construction
activities contains chemicals known to cause cancer, birth defects or other reproductive harm. Some examples of these chemicals are:
• Lead from
• Crystalline silica from bricks and cement and other masonry products, and
• Arsenic and chromium from chemically- treated lumber.
Your risk from these exposures varies, depending on how often you do this type of work. To reduce your exposure to these chemicals: work in a well ventilated area, and work with approved safety equipment, such as those dust masks that are specially designed to filter out microscopic particles.
Sound and Vibration Information
These values stated below were obtained by laboratory testing in accordance with Standard EN 50 144.
The typical sound pressure level is 89 dB (A).
The typical sound power level is 102 dB (A).
The typical weighted vibration is 1.8 m/s2.
Values measured in individual work places may be higher than the declared values. The actual exposure values and risk of harm experienced by an individual user are unique and depend upon the way the user works,
the workpiece and the workstation design, as well as upon the exposure time and the physical condition of the user.
!WARNING Wear hearing protection. Prolonged exposure to high
intensity noise can cause hearing loss.
Use thick cushioned gloves and limit the exposure time by taking frequent rest
periods. Vibration caused by the use of power tools may be harmful to your hands and arms.
