Recently, there have been a number of accidents from saw blade kickbacks when operating portable gasoline cut-off saws or “chop saws”. If you are an operator, what do you really need to know to be properly trained? What is the “proper” use of the saw?
These portable saws serve a unique function in the construction industry and especially with the utility contractors. The saw cuts through concrete or steel quickly and in place. However, they are known to have reactive forces that create the potential for saw blade kicking back towards the operator’s body!
Training and Familiarization
A minimum starting point is reading the owner’s manual for the specific model and brand you will be operating. Most cut off saw manuals will have a diagram or similar explanation of how kickbacks occur and how to reduce the possibility of a kickback. Some manufacturers have a video or representatives that can assist in training. The term kickback is used a bit differently by different saw manufacturers, but basically it refers to when the saw jumps back toward the operator. Lock-in is when the blade jams in the material and pulls the saw away from the operator. With proper use, neither of these should happen.
Kickback can be caused by using the upper part of the cutting blade or when a cut is interrupted. It also can happen when putting the blade back into a cut that’s already been started. If you must do that, make sure the blade is spinning at top speed before continuing the cut.
Selection, Inspection and Maintenance
Safety training must include knowledge of how to perform pre-use inspection and maintenance. The saws are advertized as “light-weight and rugged” and do get thrown around in the back of trucks and used in wet, cold, and muddy environments. Follow recommended practices for transportation and storage of these units. Ensure that the saw blade is mounted properly; the blade’s RPM match the saw’s capabilities, and is appropriate for the material being cut. Check that the saw guard is present, aligned, and positioned at the proper angle for the cut. Defective units must be removed from service.
A less aggressive saw blade may minimize the kickback potential. Using beveling bowls may eliminate the dangers associated with the common technique of side grinding with an abrasive blade. Use of a governor on the saw engine or a smaller saw may reduce energy/angular momentum if a kickback occurred. Using water or wet cutting can reduce reactive forces by acting as a lubricant.
Get your PPE (Personal Protective Equipment) on that will help prevent contact from a saw blade kickback, flying debris and/or noise. Approved safety glasses, hard hat with a face shield, safety shoes, hearing protection, gloves and clothing for spark protection (for metal) would be basic essentials. Respirators may be necessary if cutting is not wet.
Prepare the Work Piece
Cutting should not be performed overhead, above the shoulders, working from a ladder or other awkward position.
The work piece should be clearly visible and not obscured by soil, mud and/or water. The operator should be standing on a stable, dry surface for good footing and balance.
Move the work to a jig or work bench whenever possible to support the piece. If the piece must be cut in place, provide proper cribbing or support to prevent the blade from being pinched or the blade being kicked back.
Saw Operation for Proper Body Posture and Body Position
You must be in control of the saw at all times. Two hands must be used at all times with the thumbs wrapped around the handles. Saws are built with light-weight materials which makes it tempting for construction workers to operate the saws with one hand.
Monitor your stance, grip, and weight distribution during the cut to ensure control of the saw and that if a kickback occurred that you would be in a position to avoid the blade. Do not bend too far forward (over saw) when cutting.
Always bend at the knees and don’t bend over at the waist. Ensure that none of your body parts are in the swing area or line of travel when cutting through the material.
OSHA’s 1926 Subpart I “Tools – Hand and Power” has general coverage on Cut-Off Saws but does not have specific paragraphs for Cut-Off Saws. The general training section under 1926.21(b)(2) can be cited if training was not conducted or was inadequate.
This article is not intended to cover all aspects of Cut-Off Saw training. Training elements will vary depending on particular applications such as the type of saw, blades, materials and conditions. With any training program, an important element is to allow a new operator the opportunity to work with the saw under the direct supervision with a trained, experienced operator.
For More Information
RJF Agencies, Inc. has set up a website to act as a clearing house for information on Cut-Off Saws. The user name and password are both: sawsafety