Testing and Checking a Power Saw
By: Kevin Legacy
After running the saw to the correct operating temperature, we must now continue our equipment check to assure the saw is ready to be placed back on the apparatus for emergency use:
Check Fuel Level
Assure that the fuel tank is full, but not over full. Some machines are designed to be laid on their sides to fuel, while others are to be left upright. If you have a machine that is designed to be filled upright (slanted-fuel inlet), do not tilt the saw over to squeeze an extra ounce of fuel into the tank. Those saws require a small space at the top of the tank to allow for vapor expansion as the saw – and tank – is heated through use. Over-filling a machine can lead to failure of the tank or cap while in operation. Always fill up the machine as per Manufacturers Specifications.
Check the Blade
If composite blades are in use – aluminum oxide for steel or silicone carbide for concrete – assure that the blade is NEW: In the construction industry, in training or at an emergency scene, we will use a blade until completely worn down; However, when your saw is on the apparatus for emergency use, the blade should always start NEW. If only one cut is made at a minor incident – cutting a padlock or chain-link fence – the blade should be removed from the saw and placed in a box for training use. There is no way to tell how “used” a composite blade is: one slight imperfection or fiber tear, not visible on the exterior, can cause a catastrophic blade failure, which can cause injury to firefighters or a dangerous equipment failure when the saw is needed.
If a multi-purpose diamond blade is in use, assure that the teeth are intact: Inspect the blade for any cracks, warps or imperfections. Also inspect any welded segments that attach the teeth to the blade. When in doubt, remove the blade from service. If a carbide-tipped blade is in use: assure that the carbide teeth are present and the blade is free of roofing-tar. Once again, this blade must be checked for warping or imperfections.
Quick Look
Visually inspect the saw for housing-cracks and loose handles. Additionally, check for fluid leaks – and assure that the machine is free of tar, dust and any other debris that may negatively affect the operation and use of the saw. Remember: a well running and well-kept machine effects your operation and appearance. Have pride in your equipment.
Ready Position
When satisfied with your equipment check, place the machine on the apparatus in the “ready position”. The ready position indicates that the saw can be taken from the rig at an emergency scene, and put into operation immediately with minimal effort. When placing the saw on the apparatus, assure that the on/ off switch is in the “On-Position;” the choke is “On;” the throttle locked “On;” and the decompression button “engaged”. With the above steps already completed upon arrival, there is less of a chance of missing a start-up step at an emergency scene. Missing a step may delay getting the machine in operation, or if a step is done in the wrong order, the saw may become “flooded”, and rendered out of service for the incident. There is a very common misconception that if a choke is left “On” or the throttle-lock “Locked-On”, that a saw will flood while on the apparatus. This is another false statement as no fuel movement occurs in these saws until the starter cord is pulled.
Common Blade Problems with Cutoff Saws
When placing a blade into service on a cut-of saw: assure the blade is properly matched to the machine. All machines have a label that contains the arbor size, RPM rating and the maximum blade diameter for the machine. It is imperative that this information is clearly marked – and easily referenced when changing blades. Placing an incorrect blade on a power saw can be dangerous to the user and detrimental to the machine and the operation.
Example 1:
If a saw is rated for 5,500rpm, and a 4,000rpm blade is mistakenly placed on the saw: as the blade is throttled past 4,000rpm, the blade will begin to violently shake, and eventually come apart. When a blade comes apart, it will throw aluminum oxide fragments similar to a hand grenade. Those fragments will penetrate bunker gear!
Example 2:
If a saw has a 7/8″ arbor, and a blade with a 1″ arbor is placed on the saw, a similar outcome will unfold: The blade with the 1″ arbor will fit, but the arbor will not be snug on the shaft. When the saw is used, the blade will deteriorate from the arbor out, and will sometimes fail catastrophically.
Always use blades with matching arbor size, and RPM ratings that meet or exceed your saws specifications. Some saws accept blades from 12″- 16.” Check the manual or reference plate for the correct specifications.
Fuel Problems with Saws
In the recent past there have been several changes in fuel and how the saws run it: One major and very common problem is using old or expired fuel. Conduct your own fuel test: Place a glass jar with fresh gasoline on a shelf for three months. After three months, return with a second jar of fresh gasoline for a quick comparison. You will notice that the older gasoline will be darker in color and smell different. This is what happens INSIDE your fuel tanks.
Gasoline degrades: After three to six months, today’s untreated gasoline can cause machines to run rough or not run at all. By simply adding a fuel-stabilizer, you can slow the degrading process, which will keep fuel fresh for over six months. However, even if fuel-stabilizer is used, Brotherhood Instructors, LLC’s instructors recommend changing out the fuel in your machines and your refill cans every six months. Whenever a new batch of fuel is mixed: write the date on the can or place a tag on the can so you know how long the fuel has been in operation. When it expires, USE IT FOR TRAINING!
Another common problem is multiple mixed fuel cans on the apparatus: Not all machines run on the same fuel mixture. You may have a chain saw, a cut-off saw and a ventilation saw – but each may require a different fuel mixture (50:1, 40:1 or 32:1). With that set-up, there may be up to three different cans for as many saws.
Scenario: While operating at an emergency incident, a cut-off power saw needs to be refueled. You ask a member to bring the fuel for the cut-off saw; however, the wrong fuel can is brought accidentally. We all make mistakes, and this is certainly a realistic possibility. If you do not notice, and the wrong fuel is placed into the machine, you risk damaging the cut-off saw by running it with improper fuel.
This is a scenario that we cannot afford on an emergency incident. An easy fix to this problem is to utilize a universal fuel mix. There are many brands available commercially, and typically they are sold in a pre-measured container. For example: one packet or bottle will be added to a specified amount – usually 1 gallon of gasoline.
This mix will now run all ratios of air-cooled, two-cycle engines. These universal mixes were derived from landscapers who may own and use five or six different aircooled, two-cycle machines on one truck. To avoid carrying five or six various cans and fuel mixes, the universal mix was developed and is used extensively in their industry.
