The battery-powered cordless reciprocating saw is a new version of the old electric saw that overcomes the older tool’s disadvantages. The electric version’s main disadvantage is its need for a nearby electric power source that might not always be available. Additionally, the electric saw’s application is limited to the length of the electric cord and its extension.
 (1) A battery-powered cordless reciprocating saw cuts an automobile windshield. The blade is continuously lubricated using a foam fire extinguisher. (Photos by James Harris.) |
Now produced by various manufacturers, the cordless reciprocating saw commonly uses an 18-volt rechargeable nickel-cadmium (nicad) battery. Most manufacturers state that, under normal conditions, the battery should last between 15 and 20 minutes between charges. However, in extensive testing under heavy load, I found that the battery actually lasts between nine and 12 minutes and that a second battery was needed to continue operations. If purchasing a battery-powered saw, consider purchasing a second battery. A recently introduced 24-volt battery increases the usable power time by about 33 percent, according to manufacturers.
If planning to use a cordless reciprocating saw for operations, have an electric saw set up and ready to use. Even though the cordless saw performs satisfactorily, the electric saw does not have the operational time limitation of the rechargeable batteries, which is an important factor at extended operations.
OPERATION AND LUBRICATION
In operating a reciprocating saw, the saw’s “shoe” or “foot” in which the blade is inserted should lie flat against the material being cut. This prevents saw slippage, reduces vibration, and assists in guiding the blade as it cuts.
 (2) A cordless saw cuts an automobile’s large C post. |
Always lubricate the blade continously when it is cutting any type of metal. Based on extensive testing, a soap and water mixture works best. The best soap is any dishwashing or other household liquid soap. A few drops of liquid soap mixed with one quart of water in a plastic spray bottle should last through most any operation. Plain water is not recommended because it has no viscosity and will simply run off the blade. If the soap and water mixture runs out or is not available, a foam fire extinguisher may provide the lubrication.
Do not use oil or any petroleum product for blade lubrication. Since a blade generates heat when cutting, the petroleum product will smoke. A victim seeing this may think it is a fire and panic.
SAW BLADES
It is extremely important to use the correct blade for the operation. The wrong blade may be unable to cut the material or, worse, it may shatter and injure the victim or rescuer. Use break-resistant, bimetal cutting blades. Bimetal blades consist of 92 percent steel and eight percent cobalt for maximum flexibility. These bimetal blades are extremely durable, are somewhat shatterproof, and come in lengths between 31/2 and 12 inches.
 (3) A plastic or fiberglass vehicle body is cut to expose door hinges. |
The number of teeth per inch (TPI) determines the blade’s coarseness or fineness and ranges between three and 24 TPI. The lower the TPI, the coarser the blade; the higher the TPI, the finer the blade. Coarser blades are used to cut wood; finer blades are used to cut metal. For automobile extrication and cutting A, B, and C posts, for example, a good general-purpose nine-inch, 24-TPI blade is adequate. To cut out a windshield (Photo 1), use a three-inch, 24-TPI blade.
A rescue truck should have a large assortment of blades on hand for different applications. Depending on the material being cut, the blades may break or become dull. If possible, the department should purchase two saws and keep a second one ready to go into operation in case the blade on the other one breaks. The operation can be continued without interruption while the blade on the other saw is replaced. The operator should not rock the saw back and forth to avoid putting undue stress on the blade. The blade may shatter if it is overstressed.
BATTERY RECHARGING
A 110-volt household current battery charger comes with the cordless saw, and most manufacturers sell a 12-volt charger that can be installed on fire apparatus. Both charger versions will fully charge the battery in one hour. According to most manufacturers, the current nicad batteries do not have the same memory as the older nicads. The older batteries had to be almost completely discharged before recharging.
The newer nicads may be recharged at any point and left in the charger until needed. Once the battery is fully charged, the charger stops charging.
Keep an extra battery in the charger and another one in the saw so it is always ready to use. Alternating the battery in the charger and the one in the saw every month is an excellent idea. Do not tape the saw trigger “on” to completely discharge the battery-this can irreparably damage the unit.
 (4) This vehicle’s A posts were cut with a cordless reciprocating saw. |
Store and charge batteries in a cool, dry place. When old batteries can no longer hold a charge, they should be recycled. The materials in nicad batteries are considered hazardous and should be treated as such. Contact the manufacturer for disposal information.
CUTTING USES
Battery-powered cordless reciprocating saws are versatile. Use a small three-inch, 24-TPI blade to cut an automobile windshield. Using a hydraulic cutter can be extremely time-consuming when cutting an automobile C post, especially if the post is more than 12 inches wide. (Photo 2) A cordless saw saves precious time and frees the hydraulic tool for cutting heavier material. Moreover, the two tools can be used simultaneously without stealing power from each other. Most C posts are hollow, and the cordless saw can cut through them in no time at all.
An extrication/disentanglement operation involving a plastic or fiberglass vehicle is greatly enhanced using a cordless reciprocating saw. One saw might be used to expose the door hinges (Photo 3), and the saw or a hydraulic cutter can cut them. At a collapse scene, the cordless reciprocating saw can be placed in action immediately to cut pipe until the electric saw is available.
 (5) The vehicle’s A posts and roof were cut with a cordless saw, and the roof was flipped back. |
A battery-powered cordless reciprocating saw is a powerful addition to a department’s arsenal of rescue tools. While it is by no means an all-purpose tool, it has its place along with other rescue tools. The cordless reciprocating saw is a quick setup tool that can be put in action immediately until the electric reciprocating saw is available.
One disadvantage of the cordless reciprocating saw is that the handle on some 18-volt models is too small to hold when wearing fire gloves. The handle on the 24-volt model is larger and easier to hold.
The battery-powered cordless reciprocating saw is relatively inexpensive and re-quires minimal training since the technique used is the same as that for the electric reciprocating saw.
GARY SIEGEL recently retired from the Fire Department of New York after 24 years of service. For the past five years, he was an extrication instructor at the FDNY Academy. He presently is an instructor at the Rockland County (NY) Fire Training Center at Pomona, a New York State fire instructor, and a NYS certified accident vehicle extrication training instructor.
