Photo courtesy of David Risner
HOW TO PROPERLY USE A CIRCULAR SAW AND PREVENT KICK BACK
Among professional tradesmen, on the farm, around the house and in the vocational shop, the circular saw is probably the most commonly used power saw, and perhaps the most commonly abused. Familiarity should not breed carelessness. The following are specific safety "musts" when using any portable circular saw. Not doing so must be considered dangerous. Failure to follow these safety rules may result in serious injury.
PROPERLY USING A CIRCULAR SAW
- Always wear safety goggles or safety glasses with side shields complying with current national standard, and a full face shield when needed.
- Use a dust mask in dusty work conditions. Wear hearing protection during extended periods of operation.
- Do not wear loose clothing, jewelry or any dangling objects that may catch in rotating parts or accessories. Tie back long hair.
- Do not use a circular saw that is too heavy for you to easily control.
- Be sure the switch turns on properly. Do not use a tool if the switch does not turn it off when returned to the "off" position after release.
- Use sharp blades. Dull blades cause binding, stalling and possible kickback. They also waste power and reduce motor and switch life.
- Use the correct blade for the application. Check this carefully: Does it have the proper size and shape arbor hole? Is the speed marked on the blade at least as high as the no load RPM on the saw's nameplate?
- Check blades carefully before each use for proper alignment and possible defects. Be sure the blade washers (flanges) are correctly assembled on the shaft and that the blade is properly supported.
- Is the blade guard working? Check for proper operation before each cut.
- Check often to assure that guards return to their normal position quickly. If a guard seems slow to return or "hangs up" repair or adjust it immediately.
- Never defeat the guard to expose the blade. For example, tying back or removing the guard.
- Before starting a circular saw, be sure the power cord and extension cord are out of the blade path and are sufficiently long to freely complete the cut. A sudden jerk or pulling on the cord can cause loss of control of the saw and a serious accident.
- For maximum control, hold the saw firmly with both hands after securing the work piece. Clamp work pieces. Check frequently to be sure clamps remain secure.
- Never hold a work piece in your hand or across your leg when sawing.
- Avoid cutting small pieces of material which can't be properly secured, and material on which the base of the saw (shoe) cannot properly rest.
- When making a "blind" cut (you can't see behind what is being cut), be sure that hidden electrical wiring, water pipes or any mechanical hazards are not in the blade path. If wires are present, they must be disconnected at the power source by a qualified person or avoided. Contact with live wires could cause lethal shock or fire. Water pipes should be drained and capped. Always hold the tool by the insulated grasping surfaces.
- Set blade depth to no more than 1/8 in. to 1/4 in. greater than the thickness of the material being cut.
- When you start your saw allow the blade to reach full speed before the work piece is contacted. Be alert to the possibility of the blade binding and kickback occurring, (see "preventing Portable Circular Saw Kickback").
- If a fence or guard board is used, be certain the blade is kept parallel with it.
- NEVER overreach!
- Crowded, cluttered conditions that can cause tripping, or loss of balance are particularly dangerous.
- When making a partial cut, or if power is interrupted, release the trigger immediately and don't remove the saw until the blade has come to a complete stop.
- Never reach under the saw or work piece.
- Portable circular saws are not designed for cutting logs, or roots, trimming trees or shrubs. These are very hazardous practices.
- Switch the tool off after a cut is completed, and keep the saw away from your body until the blade stops.
- Unplug, clean and store the tool in a safe, dry place after use.
PREVENTING PORTABLE CIRCULAR SAW KICKBACK
Kickback is a sudden reaction to a pinched blade, causing an uncontrolled portable tool to lift up and out of the work piece toward the operator. Kickback is the result of tool misuse and/or incorrect operating procedures or conditions. Take these specific precautions to help prevent kickback when using any type of circular saw:
- Keep saw blades sharp. A sharp blade will tend to cut its way out of a pinching condition.
- Make sure the blade has adequate set in the teeth. Tooth set provides clearance between the sides of the blade and the work piece, thus minimizing the probability of binding. Some saw blades have hollow ground sides instead of tooth set to provide clearance.
- Keep saw blades clean. A buildup of pitch or sap on the surface of the saw blade increases the thickness of the blade and also increases the friction on the blade surface. These conditions cause an increase in the likelihood of a kickback.
- Be very cautious of stock which is pitchy, knotty or warped. These are most likely to create pinching conditions and possible kickback.
- Always hold the saw firmly with both hands.
- Release the switch immediately if the blade binds or the saw stalls.
- Support large panels so they will not pinch the blade. Use a straight edge as a guide for ripping.
- Never remove the saw from a cut while the blade is rotating.
- Never use a bent, broken or warped saw blade. The probability of binding and resultant kickback is greatly increased by these conditions.
- Overheating a saw blade can cause it to warp and result in a kickback.
- Buildup of sap on the blades, insufficient set, dullness and unguided cuts, can all cause an overheated blade and kickback.
- Never set a blade deeper than is required to cut the work piece 1/8 in. to 1/4 in. greater than the thickness of the stock is sufficient. This minimizes the amount of saw blade surface exposed and reduces the probability and severity if any kickback does occur.
- Minimize blade pinching by placing the saw shoe on the clamped, supported portion of the work piece and allowing the cut off piece to fall away freely.
Above information taken from THE TOOL GURU: How to properly use a Circular Saw and prevent kick back.
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