TB 44: Rotary Saw Flashcards
The rotary saw is a versatile high speed, hand held, gas powered cutting device designed to cut solid materials such
steel, wood, masonry or polycarbonate
utilized in a variety of operations such as
forcible entry, ventilation and USAR operation
Each rotary saw will have access to several different
blade types, a scrench tool, and a blade board
allows for members to have a variety of options while on scene of an emergency
The LAFD carries 4 types of 14” rotary saw blades. What are they?
Abrasive Blade
Combi-Blade
Diamond Blade
Carbide Tooth Blade
Each blade type has a specific use. Each rotary saw should be accompanied by a blade board that has an assortment of blades that best fits the needs of the district. All companies shall have at least
one of each blade type available
METAL CUTTING ABRASIVE BLADES
- consists of grit bonded by an organic binder
- Reinforced blades” are made up of a fabric or fiber base, preventing total breakage at maximum working speed
- used on steel, steel alloys and other hard metals
-not be used on soft metals such as aluminum or brass
Blades shall be a minimum of
12” to remain in front line service.
Blades used during emergency operations may become
smaller while performing extensive cutting operations
-used until it is no longer effective or safe
Blades smaller than 12” may be used for
training purposes
Blades below 9” shall be sent into
shops for replacement
Abrasive blades shall be removed from service if there are signs of
petroleum product contamination or cracks
-could render the blade unsafe
Blades that are no longer safe for use shall be marked with
F-175 Tag
word “UNSAFE” shall be marked on the blade
COMBINATION “COMBI” BLADE
- diamond blade that consists of a steel flat metal disc with synthetic diamonds bonded to the outer edge
- do not have teeth to cut; rather they have exposed diamond crystals used to grind the material
Stamping or printing by the manufacture near the arbor with “Metal/Steel”, “Metal Cutting”, or “Concrete/Metal” indicates
combination use blade
Combi-blades can be used to cut
bare metal, concrete, reinforced concrete, masonry or Robertson Decking
-All Combi-blades are bi-directional
Combi-blade is not designed to cut
soft metals such as brass or aluminum
-however it can cut thin, soft metal found on train siding, aircraft siding, metal clad doors, or aluminum gates
Any glazing or buildup of material on the diamond segment can be cleaned by
cutting into a soft material such as brick, cinder block or asphalt
After several thousand grinding rotations, the exposed matrix holding the diamonds begins to
wear and fracture
Matrix erosion exposes new sharp diamonds. This cycle of erosion and exposing continues until
all of the diamond and bond section of the segment is gone
Combi-blade had a continuous cutting depth of
4¾”
Combi-blades shall be forwarded to Supply and Maintenance for replacement when:
- Any one segment is fractured, broken or missing.
- Bald spots along any of the segments occur.
- Matrix bond is equal to the thickness of the blade body; a step or lip no longer exists
CONCRETE DIAMOND BLADES
similar in construction to the Combi-blade
- designed as a directional cutting rotation
- arrow stamped or printed on the blade indicating the proper rotation
Concrete diamond blades are designed to
Cut concrete and metal encased in concrete
*Do not attempt to cut bare metal with this blade!
Glazing or build-up of material on the diamond segments, can be cleaned by
Cutting in a soft material such as brick, cinder block or asphalt
As with the Combi-blades, Diamond blades shall be forwarded to Supply and Maintenance for replacement when
- Any one segment is fractured, broken or missing.
- Bald spots along any of the segments occur.
- Matrix bond is equal to the thickness of the blade body. No step or lip exists.
CARBIDE TIP BLADE
tempered metal blade, carbide tipped
- cutting composition roofing material, wood, and Lexan
- Use on light sheet metals such as door cladding or aluminum sheet with care
- After use, check damage and sharpness. If a missing tip or a visible radius appears, fill out a F-175 tag and send the blade to Supply and Maintenance for replacement
safety equipment should be used while operating the saw
Gloves
Eye Protection
Helmet
Brush Jacket/Turn out coat
Engage the half throttle. This is accomplished by engaging the throttle and
depressing the throttle lock button on the left side of the throttle assembly
Pulling out the choke on the K-970 will
Activate the half throttle position
The half throttle will remain engaged until the throttle trigger is
Engaged even if the choke is pushed back in
What will assist in starting the saw?
Pressing in the compression valve
Automatically returns to its initial position when the saw starts
On the K-970, how many times do you press the air purge diaphragm?
6 times
What happens when you push the air purge diaphragm?
Fuel is pumped through to the carb
Fewer pulls will be required for starting
What are the two starting methods?
Ground Start or Drop Start
Ground Start Procedures:
- Grip front handle with left hand
- Right foot on lower section of rear handle
- Slowly pull cord with right hand, until resistance is felt
- Pull firmly and rapidly
- Pull cord to chest with right hand
-DO NOT pull the started cord all the way or let go of handle when cord is fully extended
Drop Start Procedure:
- Grip from handle with left hand
- Stand upright, saw waist level
- Keep blade away from body at all times
- Right hand on starting handle, fully extend left arm down while pulling firmly and rapidly on starting handle towards chest
Does the cutting blade rotate when the engine is started?
Yes
Flooding Procedures:
- Choke pushed in
- Half Throttle engaged (allows maximum amount of air to flow through carburetor, combustion chamber and out exhaust)
- Pull cord 4-5 times (air to fuel mix lower, saw will start)
How does flooding occur?
Starter cord continually pulled while remaining in choked position after the saw pops or attempts to start
Fuel mixture in combustion chamber becomes too fuel rich until chamber is cleared of fuel
To prevent from binding:
- Adjust blade guard for cutting depth
- Enter cuts at fu RPMs
- Cut in straight line (Do not twist)
- Let the saw work without forcing or pressing the blade
- Release throttle and immediately remove blade if occurs (avoid belt damage)
Which position is best when used during ventilation or extended concrete cutting operations:
Inboard position
Protects user from debris
What are some cutting procedures options?
Vertical Cut Low Horizontal Cut Low Vertical Cut Mid Horizontal Cut Mid Vertical Cut High Horizontal Cut High
Carrying Aloft (12’ Utility Strap):
- Larks foot around top of handle
- Clip on itself with carabiner around throttle handle
- Sling strap across chest to opposite shoulder
- Position close to SCBA bottle
Carrying Aloft (Equipment Carrying Strap):
- Clip on itself around throttle handle and other end to backpack frame of SCBA
- Place over shoulder, then opposite side of SCBA bottle
- Position saw at SCBA bottle level by adjusting carrying strap
Inboard: With the blade centered it reduces blade bind and provides better balance of the saw during ops such as:
Vertical ventilation on a roof or cutting concrete
Inboard: The saw can be dragged through the material by using the _____, and the lower portion of the carrying handle as a ____?
Depth Gauge, Pivot and Skid
What is the position of choice for forcible entry because it permits making flush cuts close to the walls and floors?
Outboard
What are daily maintenance?
Fuel Starting Position Blade Guard Belt Tension Visual Inspection Blades and Blade Board Carrying Strap
Weekly Check:
Perform Daily Check Start & run till warm Run to high RPM Check for: Abnormal Sounds Abnormal Vibration Inspect starter cord
Monthly Check:
Check: Cutting head assembly Drive Belt Clutch assembly Air Filter Spark Plug Muffler Replace fuel if needed
After Use:
Refuel Blade/Blade Guard Air Filter Visual Inspection Clean entire saw Start & Run Saw
What type of fuel does the saw take?
50:1 Two stroke fuel mixture
Making two-stroke fuel:
Fill container half amount of gas
Add entire two stroke oil
Mix (Shake)
Add remaining amount of gas
*Do not make more than one months supply of fuel at a time
Current LAFD policy is to replace fuel in small engines every ___ days with fresh fuel
30 days
What are two forms of stabilizer to keep gas fresh
Sta-bil or
Seafoam
Gas to 2 cycle oil ratio:
1 Gal - 2.6 oz
2.5 Gal - 6.5 oz
5 Gal - 13 oz
Which form should the weekly checks be documented on?
F-973W
During a weekly check, depress the throttle fully for ____ seconds to bring up the RPMs and allow the saw to return to idle before repeating the process how many times?
1-2 Seconds/ 2-3 Times
With the engine stopped, slowly pullout the starter cord and inspect for:
General condition and fraying
The starting cord should fully retract into the cover. If it fails to fully retract or shows signs of damage, contact:
Small Engine Repair shop at S&M
When monthly checks are performed, where should you document it at?
F-973M
Perform Monthly checks, one saw at a time
When completed, perform a daily check prior to putting the saw back into service
To check the Cutting Head Assembly:
- Remove blade and check guard for debris
- Losses drive belt, check arbor or clutch assembly that rotates freely without roughness
- Arbor or clutch can not be checked with tension on belt
When cleaning the air filter, to remove trapped debris, tap the filter gently on the…
Palm of your hands
What should not be used when cleaning a paper filter?
Compressed air or solvents
Who do you contact when filter is unserviceable?
S&M for replacement
During which operation should special attention be given to the condition of the filter?
During extended dusty ops such as concrete cutting
If the spark plug is dirty, what do you clean it with?
What is the electrode gap on the spark plug?
Wire Brush
.020” (0.5mm)
How will the saw react if the spark plug has a issue or needs to be replaced??
Low on power
Difficult to start
Runs poorly at idle speed
When does the rotary taken to the small engine repair shop to be inspected by S&M personnel?
Annually
During Annual Pump Test or Aerial Ladder Test
What do you use to clean the exterior of the saw?
Water with mild detergent
When cleaning the engine parts, where should you pay attention to the most?
Cylinder and head fins if soiled with such material as molten tar, clean with degreaser
What do you want avoid cleaning with petroleum-based products?
Belt
Pull-Cord
Blade
Could damage integrity
How long does the blade continue to rotate after the engine has stopped?
Up to a minute
*let blade slow down or stop. In the material
Which area do you not use the blade for cutting?
Kickback zone
Reactive force will push the saw up and back towards the user
What should be used If electrical hazards are suspected or exists?
Gauntlet gloves shall be used
How far can sparks be thrown up to?
30 Feet
Where should you NOT use the rotary saw?
In flammable atmospheres
Electrical vault fires
Tanker spills or leaking of natural gas
To protect personnel or patients from showering sparks, move personnel, change the angle of your saw, or use non-sparking tools. If those options are not practical, at a minimum,
utilize an aluminized blanket to protect personnel or patients.
