CHAPTER 38

Tools and Techniques

38-1

CHAPTER 38

POWER TOOLS – SAWS

38 POWER TOOLS – SAWS

Basic Saw Safety

• Wear protective clothing and equipment (see the

chapters on personal protective equipment in this

manual). Eye protection is essential and hearing

protection is recommended (see Table 38-1).

• Where saws are used in conﬁned spaces or for

prolonged periods, wear hearing protection.

• Where ventilation is inadequate, wear an

appropriate respirator for protection against dust.

Over time, exposure to dust from particle board

or medium-density ﬁbreboard (MDF) and other

materials may cause respiratory problems.

• With electric saws operated outdoors or in wet

locations, you must use a ground fault circuit

interrupter (GFCI). Inspect extension cords to

ensure they are in good condition before use.

• Never wear loose clothing, neck chains, scarves,

or anything else that can get caught in the saw.

• Leave safety devices in place and intact on the saw.

Never remove, modify, or defeat guards. Keep your

free hand away from the blade (Figure 38-1).

• Whenever possible, select the lightest tool or the

tool with the least vibration. Wear anti-vibration

gloves if provided by the employer.

• Always change and adjust blades with the power

OFF. Disconnect electric saws from the power

source before making changes or adjustments.

Brick Saw 94

Chop Saw/Mitre Saw 92

Circular Saw 88

Concrete Saw 98

Cutoff Saw 98

Framing Saw 82

Jigsaw 91

Portable Handheld Band Saw 83

Quick-Cut Saw 105

Reciprocating Saw 105

NOTE: Where noise levels exceed 85 dBA, control measures must

be taken.

Tool

Minimum Noise

Level (dBA)

Table 38-1: Noise Levels of Power Saws

Figure 38-1: Keep Hand Away from Blade

Circular Handsaws

The two models most often used on construction

sites are the worm-drive saw (Figure 38-2) and the

direct-drive saw (Figure 38-3). The main difference

between the two lies in the drive action. The worm-

drive saw has gears arranged so that the blade runs

parallel to the motor shaft. The direct-drive saw has

the blade at a right angle to the motor shaft.

The worm-drive saw periodically requires special

gear oil to keep the inner gears lubricated. This

requirement is usually eliminated in the direct-drive

saw, which has sealed bearings and gears.

Both saws must be inspected regularly for defects,

and operated and maintained in accordance with

manufacturers’ recommendations.

Check for

– damaged cord – loose blade

– faulty guards – defective trigger

– chipped or missing – cracked or damaged

– teeth – casing

Upper

Blade

Guard

Quadrant

Lever for Retracting

Lower Blade Guard

Bevel

Adjustment

Lever

Quadrant

Motor Housing

Trigger

Switch

Trigger

Guard

Electric

Cord

Depth

Adjustment

Knob

Brush Cap

Shoe

Lower

Blade

Guard

Outer

Arbor

Washer

Blade Stud

Guide

Notch

Figure 38-2: Worm-Drive Saw

Trigger Switch

Pull “On”-Release “Off”

Motor Housing

Bevel Cutting Angle

Adjustment Knob

Knob

Handle

Main

Shoe

Front Clamp

Screw

Cutting Depth

Adjustment Knob

Shoe

Lower Blade

Guard

Sawdust

Ejection Chute

Lever for Retracting

Lower Blade Guard

Electric

Cord

Figure 38-3: Direct-Drive Saw

38-2

Construction Health and Safety Manual

POWER TOOLS – SAWS

Safety Features

Sawdust Ejection Chute

This feature prevents sawdust from collecting in

front of the saw and obscuring the cutting line. The

operator can continue cutting without having to

stop the saw and clear away sawdust.

Clutch

Some worm-drive saws are equipped with a clutch to

prevent kickback. Kickback occurs when a saw meets

resistance and violently backs out of the work. The

clutch action allows the blade shaft to continue

turning when the blade meets resistance. The blade

stud and friction washer can be adjusted to provide

kickback protection for cutting different materials.

Check friction washers for wear.

Brake

An electric brake on some circular saws stops the

blade from coasting once the switch is released. This

greatly reduces the danger of accidental contact.

Trigger Safety

On some light-duty saws, a latch prevents the

operator from accidentally starting the motor.

The trigger on the inside of the handle cannot

be pressed without ﬁrst pressing a latch on the

outside of the handle. On heavy-duty saws, a

bar under the trigger switch helps to prevent

accidental starting.

Blades

Blades should be sharpened or changed frequently

to prolong saw life, increase production, and

reduce operator fatigue. The teeth on a dull or

abused blade will turn blue from overheating.

Cutting will create a burning smell. Such blades

should be discarded or reconditioned.

Before changing or adjusting blades, disconnect

the saw from the power source.

Take care to choose the right blade for the job.

Blades are available in a variety of styles and tooth

sizes. Combination blades (rip and crosscut) are

the most widely used.

Ensure that arbor diameter and blade diameter are

right for the saw.

Because all lumber is not new, make sure it is

clean and free of nails, concrete, and other foreign

objects. This precaution not only prolongs blade life

but may also prevent serious injury.

Take special care to ensure that blades are installed

in the proper rotational direction (Figure 38-4).

Remember that electrical circular handsaws cut

with an upward motion. The teeth visible between

the upper and lower guard should be pointing

toward the front of the saw. Most models have a

directional arrow on both blade and guard to serve

as a guide.

Figure 38-4: Blades Must Be Installed

in the Proper Rotational Direction

Blade Guards

Never operate an electric saw with the lower guard

tied or wedged open. The saw may kick back and cut

you, or another worker may pick up the saw and—not

knowing that the guard is pinned back—get hurt.

Incidents have also occurred when the operator

forgot that the blade was exposed and put the saw

on the ﬂoor. The blade, still in motion, made the

saw move, cutting anything in its path.

Make sure that the lower guard returns to its

proper position after a cut. Never operate a saw

with a defective guard-retracting lever.

On most saws, the lower guard is spring-loaded

and correct tension in the spring will automatically

close the guard. However, a spring weakened by

use and wear can allow the guard to remain open

after cutting. This creates a potential for injury

if the operator does not realize that the blade is

still turning and rests it against a leg, for example.

Always maintain complete control of the saw until

the blade stops turning. The guard may also be

slow to return after 45° cuts.

Choosing the Proper Blade

For safety, saw operators must understand the

different designs and uses of blades. Blades

unsuited for the job can be as hazardous as dull

blades. For instance, a saw ﬁtted with the wrong

blade for the job can run hot so quickly that blade

tension changes and creates a wobbly motion.

The saw may kick back dangerously before the

operator can switch it off.

Resharpened blades can be substantially reduced

in diameter—for instance, from nine to eight inches.

Make sure that the blade diameter and arbor

diameter are right for the saw.

When using carbide-tipped blades, take special

care not to strike metal. The carbide tips can come

loose and ﬂy off, ruining the blade and injuring the

operator. Inspect the blade regularly for cracked or

missing tips.

Tools and Techniques

38-3

POWER TOOLS – SAWS

Crosscut Blade (Figure 38-5) — The bevelled

sharp-pointed teeth are designed to cut the

crossgrain in wood. Size and bevel of the teeth

are important factors in cutting different woods.

Softwood requires bigger teeth to carry off the

sawdust. Hardwood requires ﬁne teeth with many

cutting edges. Note the different angles and edges

needed for cutting hardwood and softwood.

Bevelled this side

Bevelled

opposite

side

10° Angle for Hardwood

30° Angle for Softwood

10° Bevel for Hardwood

40° Bevel for Softwood

Figure 38-5: Crosscut Blade

Ripsaw Blade (Figure 38-6) — The ﬂat sharp teeth

are designed to cut the long grain in wood. They are

neither bevelled nor needle-pointed. Needle-pointed

teeth would get clogged and the blade would

become overheated. Never use a ripsaw blade for

crosscutting or for cutting plywood. The material can

jam and overheat the blade or splinter in long slivers

that may seriously injure the operator.

Not Bevelled

10° Angle for Hardwood

30° Angle for Softwood

Figure 38-6: Ripsaw Blade

Combination Blade (Figure 38-7) – This blade

combines features of the crosscut and ripsaw

blades. It can be used for crosscutting and ripping,

or for cutting plywood. Carpenters on construction

sites prefer the combination blade for rough

woodwork such as stud walls and formwork

because they don’t have to change blades. The

teeth are alternately bevelled and have a straight

front. The heel of each tooth is not lower than the

heel of the tooth on either side of it.

Maximum

Slopeline

Bevelled Alternately

Figure 38-7: Combination Blade

Standard Combination or Mitre Blade (Figure

38-8) – This is mainly used by trim carpenters.

It includes teeth for crosscutting, raker teeth for

ripping, and deep gullets for carrying off sawdust.

The blade can be used for cutting both hardwood

and softwood and for mitring.

Raker Tooth

(not bevelled)

Crosscut Teeth

(bevelled alternately)

Sawdust Collector

(gullet)

Figure 38-8: Standard Combination or Mitre Blade

Changing, Adjusting, and Setting Blades

When changing blades, take the following precautions.

1. Disconnect the saw from the power source.

2. Place the saw blade on a piece of scrap lumber

and press down until the teeth dig into the

wood (Figure 38-9). This prevents the blade

from turning when the locking nut is loosened or

tightened. Some machines are provided with a

mechanical locking device.

3. Make sure that keys and adjusting wrenches are

removed before operating the saw.

Figure 38-9: Dig the Teeth into Scrap

Wood Before Changing Blades

Proper adjustment of cutting depth keeps blade

friction to a minimum, removes sawdust from

the cut, and results in cool cutting. The blade

should project the depth of one full tooth below

the material to be cut (Figure 38-10). When using

carbide-tipped blades or mitre blades let only half a

tooth project below the material.

Figure 38-10: Proper Blade Depth

If the blade is to run freely in the kerf (saw cut),

teeth must be set properly, that is, bent alternately

(Figure 38-11). The setting of teeth differs from

one type of blade to another. Finer-toothed blades

require less set than rougher-toothed blades.

38-4

Construction Health and Safety Manual

Figure 38-11: Ensure Teeth Are Set Properly

In general, teeth should be alternately bent 1/2

times the thickness of the blade. Sharp blades

with properly set teeth will reduce the chance of

wood binding. They will also prevent the saw from

overheating and kicking back.

Cutting

Place the material to be cut on a rigid support such

as a bench or two or more sawhorses. Make sure that

the blade will clear the supporting surface and the

power cord. The wide part of the saw shoe should

rest on the supported side of the cut if possible.

Plywood is one of the most difﬁcult materials to cut

with any type of saw. The overall size of the sheet

and the internal stresses released by cutting are the

main causes of difﬁculty. Large sheets should be

supported in at least three places, with one support

next to the cut.

Short pieces of material should not be held by

hand. Use some form of clamping to hold the

material down when cutting it (Figure 38-12).

Figure 38-12: Use a Clamp When

Cutting Short Pieces of Material

NEVER use your foot or leg to support the

material being cut. Too many operators have

been seriously injured by this careless act.

The material to be cut should be placed with its

good side down, if possible. Because the blade cuts

upward into the material, any splintering will be on

the side that is uppermost.

Use just enough force to let the blade cut without

labouring. Hardness and toughness can vary in

the same piece of material, and a knotty or wet

section can put a heavier load on the saw. When

this happens, reduce pressure to keep the speed

of the blade constant. Forcing the saw beyond its

capacity will result in rough and inaccurate cuts. It

will also overheat the motor and the saw blade.

Take the saw to the material. Never place the saw

in a ﬁxed, upside-down position and feed material

into it. Use a table saw instead.

If the cut gets off line, don’t force the saw back

onto line. Withdraw the blade and either start over

on the same line or begin on a new line.

If cutting right-handed, keep the cord on that side

of your body. Stand to one side of the cutting line.

Never reach under the material being cut.

Always keep your free hand on the long side of

the lumber and clear of the saw. Maintain a ﬁrm

grip on the saw and keep a well-balanced stance,

particularly when working on uneven footing

(Figure 38-13).

Figure 38-13: Maintain a Firm Grip on Saw and Keep

Free Hand on the Long Side of Material

Plywood, wet lumber, and lumber with a twisted

grain tend to tighten around a blade and may

cause kickback. Kickback occurs when an electric

saw stalls suddenly and jerks back toward the

operator. This may cause severe injury.

Pocket Cutting

Follow these steps with extreme care

(see Figure 38-14).

1. Tilt saw forward.

2. Rest front of shoe on wood.

3. Retract lower guard.

4. Lower saw until front teeth almost touch wood.

5. Release guard to rest on wood.

6. Switch on the saw.

7. Keep the saw tilted forward and push it down

and forward with even pressure, gradually

lowering it until shoe rests ﬂat on wood.

POWER TOOLS – SAWS

Tools and Techniques

38-5

Figure 38-14: Steps for Making a Pocket Cut

Sabre Saws

The sabre saw, or portable jigsaw (Figure 38-15), is

designed for cutting external or internal contours.

The saw should not be used for continuous or

heavy cutting that can be done more safely and

efﬁciently with a circular saw.

Switch

Unplug the saw

before making

repairs or

adjustments.

Air Vents

Auxiliary

Handle

Chuck

Shoe or

Base

Slot for

Edge Guide

Figure 38-15: Sabre Saw (Jigsaw)

The stroke of the sabre saw is about 1/2 inch for

the light-duty model and about 3/4 inch for the

heavy duty model. The one-speed saw operates

at approximately 2,500 strokes per minute. The

variable-speed saw can operate from one to 2,500

strokes per minute.

The reciprocating saw (Figure 38-16) is a heavier

type of sabre saw with a larger and more rugged

blade. The tool is often used by drywall and

acoustical workers to cut holes in ceilings and

walls. Equipped with a small swivel base, the saw

can be used in corners or free-hand in hard-to-

reach places. The reciprocating saw must be held

with both hands to absorb vibration and to avoid

accidental contact.

Eye protection is a must when working with a

jigsaw or reciprocating saw. You may also need

respiratory protection such as an N-95 ﬁltering

facepiece.

Figure 38-16: Reciprocating Saw

Use caution when cutting through walls. Beware of

electrical wiring and other services in or behind the

wall (Figure 38-17).

Figure 38-17: Beware of Electrical Wiring and Other

Hazards When Cutting Through Walls

Choosing the Proper Blade

Various blades, ranging from 7 to 32 teeth per inch,

are available for cutting different materials. For

the rough cutting of stock such as softwood and

composition board, a blade with 7 teeth per inch will

cut the fastest. For all-round work with most types of

wood, a blade with 10 teeth per inch is satisfactory.

Cutting

The sabre saw cuts on the upstroke. Therefore,

splintering will occur on the top side of the material

being cut. To prevent this, make sure that the good

side is facing down. The degree of splintering will

depend on the type of blade, the vibration of the

material, and the feed of the saw.

To avoid vibration, the material should be clamped

or otherwise secured and supported as close to

the cutting line as possible. If the material vibrates

excessively or shifts during cutting, the saw can run

out of control, damaging the blade and injuring the

operator.

POWER TOOLS – SAWS

38-6

Construction Health and Safety Manual

• Before starting a cut, make sure that the saw will

not contact clamps, the vise, workbench, or other

support.

• Never reach under the material being cut.

• Never lay down the saw until the motor has

stopped.

• Do not try to cut curves so tight that the blade

will twist and break.

• Always hold the base or shoe of the saw in ﬁrm

contact with the material being cut.

WARNING: When sawing into ﬂoors, ceiling, or

walls, always check for plumbing and wiring.

External Cut

To start an external cut (from the outside in), place

the front of the shoe on the material (Figure 38-18).

Make sure that the blade is not in contact with the

material or the saw will stall when the motor starts.

Hold the saw ﬁrmly and switch it on. Feed the

blade slowly into the material and maintain an even

pressure. When the cut is complete, do not lay

down the saw until the motor has stopped.

Rest front

shoe on

material.

Blade should not

touch material before

saw is switched on.

Make sure that the

cut will clear bench

or other support.

Clamp or otherwise

secure the material

ﬁrmly in place.

Figure 38-18: Starting an External Cut

Inside Cuts

To start an inside cut (pocket cut), ﬁrst drill a lead

hole slightly larger than the saw blade (Figure

38-19). With the saw switched off, insert the blade

into the hole until the shoe rests ﬁrmly on the

material. Do not let the blade touch the material

until the saw has been switched on.

It is possible to start an inside cut without drilling

a lead hole ﬁrst — but only when it’s absolutely

necessary. To do this, tip the tool forward so that

the front edge of the shoe rests on the workpiece

and the teeth of the blade face the material. Keep

the blade out of contact with the material.

Lead Hole

Spacers

provide

clearance to

prevent blade

from hitting

bench

Figure 38-19: Starting an Inside Cut

Switch on the saw and slowly feed the blade into the

material while lowering the back edge of the shoe.

When the shoe rests ﬂat on the material and the

blade is completely through, proceed with the cut.

Any change from this procedure can cause the blade

to break and injure the operator or workers nearby.

Never try to insert a blade into, or withdraw a blade

from, a cut or a lead hole while the motor is running.

Never reach under the material being cut.

Chainsaws

Chainsaws can be powered by electric motors

(Figure 38-20) or gasoline engines (Figure 38-21).

Figure 38-20: Electric Chainsaw

Front Handle

Front Hand Guard

(activates chain brake)

Guide Bar

Chain

Drive Sprocket

Rear Handle

and Guard

Scabbard-Type

Chain Guard

Trigger Lock

Throttle Trigger

Fuel Cap

Figure 38-21: Gasoline-Powered Chainsaws

POWER TOOLS – SAWS

Tools and Techniques

38-7

Both saws are designed to provide fast-cutting

action with a minimum of binding in the cut, even

though wood may be sap-ﬁlled or wet. Both

afford about the same performance in terms of

horsepower and they are equipped with similar

controls and safety devices.

While the chainsaw is relatively easy to operate,

it is the cause of many serious injuries in Ontario

construction each year. As with all high-speed

cutting tools, it demands the full attention of even

the trained and experienced operator.

Generally the injuries result from two types of

incidents:

1) The operator makes accidental contact with the

revolving chain

2) The operator is struck by the object being cut,

usually a tree or heavy limb.

Requirements

Regulations require that chainsaws used in

construction must be equipped with a chain brake.

Make sure that the saw is equipped with a chain

brake mechanism, and not simply a hand guard,

which is similar in appearance. Also, make sure that

the chain brake is operational.

Regulations also require that chainsaws used in

construction must be equipped with “anti-kickback”

chains. Called safety chains by the manufacturers,

these chains incorporate design features intended

to minimize kickback while maintaining cutting

performance (Figure 38-22).

Drive Tang

Low-Proﬁle Cutter

Guard Link

Depth Gauge

Figure 38-22: Safety Chain

Protective Clothing and Equipment

• Eye protection in the form of plastic goggles is

recommended. A faceshield attached to the hard

hat will not provide the total eye protection of

close-ﬁtting goggles.

• Leather gloves offer a good grip on the

saw, protect the hands, and absorb some

vibration. Gloves with ballistic nylon reinforcement

on the back of the hand are recommended.

• Since most chainsaws develop a high decibel

rating (between 95 and 115 dBA depending on age

and condition), adequate hearing protection must

be worn, especially during prolonged exposure.

• Trousers or chaps with sewn-in ballistic nylon

pads provide excellent protection, particularly for

the worker who regularly uses a chainsaw.

Kickback

Kickback describes the violent motion of the

saw that can result when a rotating chain is

unexpectedly interrupted. The cutting chain’s

forward movement is halted and energy is

transferred to the saw, throwing it back from the

cut toward the operator.

The most common and probably most violent

kickback occurs when contact is made in the

“kickback zone” (Figure 38-23).

Figure 38-23: Kickback Zone

Contact in this zone makes the chain bunch up

and try to climb out of the track. This most often

happens when the saw tip makes contact with

something beyond the cutting area such as a tree

branch, log, or the ground.

To minimize the risk of kickback, follow these

practices.

• Use a low-proﬁle safety chain.

• Run the saw at high rpm when cutting.

• Sharpen the chain to correct speciﬁcations.

• Set depth gauges to manufacturers’ settings.

• Maintain correct chain tension.

• Hold the saw securely with both hands.

• Don’t operate the saw when you are tired.

• Know where the bar tip is at all times.

• Don’t allow the cut to close on the saw.

• Make sure the chain brake is functioning.

Starting

When starting, hold the saw ﬁrmly on the ground

or other level support with the chain pointing away

from your body and nearby obstructions. Use a

quick, sharp motion on the starter pull (Figure

38-24). Never “drop start” the saw. This leaves only

one hand to control a running saw and has resulted

in leg cuts. Use the proper grip (Figure 38-25).

Saw with

Step-In Handle

Figure 38-24: Correct Starting Position

POWER TOOLS – SAWS

38-8

Construction Health and Safety Manual

Note

thumb

position

Note

thumb

position

Figure 38-25: Proper Grip

Site Hazards

• Before moving from place to place, shut off

the saw and walk with the guide bar pointed

backwards. A trip or a stumble with a running

saw can cause serious injury (Figure 38-26).

• Take extra care when making pocket cuts (Figure

38-27). Start the cut with the underside of the

chain tip, then work the saw down and back to

avoid contact with the kickback zone. Consider

an alternative tool such as a sabre saw.

• Be particularly careful to avoid contact with

nails, piping, and other metallic objects. This is

especially important when making a pocket cut

through framing lumber such as for a subﬂoor

or when cutting used lumber such as for trench

shoring, lagging, or blocking timbers.

• Use chainsaws to cut wood only. They are not

designed to cut other materials.

• When using a chainsaw to trim rafter ends, take

the following steps to avoid injury:

- Cut down from the top of the rafter. Don’t cut

from underneath.

- When performing a pocket cut, you could be

creating a fall hazard. Make sure you use fall

protection to avoid this hazard.

- Work from a secure scaffold at eaves level.

Cutting with a chainsaw from a ladder is

dangerous and should not be considered.

- The extension cord on an electric chainsaw

should be secured on the roof above the

operator with enough working slack. This will

prevent the weight of a long cord from pulling

the operator off balance.

- Keep both hands ﬁrmly on the saw.

Figure 38-26: How to Walk with Chainsaw

RIGHT WRONG

Figure 38-27: Pocket Cuts

Maintenance

Well-maintained cutting components are essential

for safe operation. A dull or improperly ﬁled chain

will not only slow the cutting operation but also

increase the risk of kickback.

• Inspect and maintain your saw according to

the manufacturer’s recommendations regarding

chain tension, wear, replacement, etc. Check for

excessive chain wear and replace chain when

required. Worn chains may break.

• Select the proper size ﬁles for sharpening the

chain. Two ﬁles are necessary:

1) a ﬂat ﬁle for adjusting depth gauge

2) a round ﬁle of uniform diameter for

sharpening cutters and maintaining drive links.

• You must choose the correct round ﬁle for your

chain to avoid damaging the cutters. Consult the

owner’s manual or the supplier to be sure of ﬁle size.

• A round ﬁle used in combination with a ﬁle holder

or, better yet, a precision ﬁling guide will give the

best results (Figure 38-28).

Precision Filing Guide

Chain

File Holder

Check the owner’s manual for

recommended ﬁling angle

Round

File

Figure 38-28: Sharpening Tools

POWER TOOLS – SAWS

Tools and Techniques

38-9

Adjusting Chain Tension

• Follow the manufacturer’s instructions on chain

tension.

• In general, the chain should move easily around

the bar by hand without showing noticeable sag

at the bottom (Figure 38-29).

• Be generous with chain lubricating oil. It is almost

impossible to use too much. Most late model

saws have automatic oilers. But operators must

still remember to ﬁll the chain-oil reservoir.

Too Tight

Too Loose

Correct Tension

1/8 inch

Figure 38-29: No Noticeable Sag in Chain

Chop Saws

Increasingly, carpenters and other trades are using

chop saws to cut various materials (Figure 38-30).

These portable saws offer quick, efﬁcient, and

economical cutting.

Figure 38-30: Chop Saws

Unfortunately, like all power equipment, chop saws

pose serious hazards for the unwary or untrained

operator. Follow Basic Saw Safety (at the beginning

of this chapter) and Safety Basics (at the beginning

of the chapter on “Power Tools – Drills, Planes,

Routers), the same as for other power saws.

Most of these saws are equipped with abrasive

wheels for quick cutting through metal studs and

other material.

• Select the proper abrasive cutting wheel for the

material being cut. For metals, use aluminum

oxide. For masonry, stone, and concrete, use silica

carborundum.

• The rpm of the saw should not exceed the

recommended rpm printed on the blade label.

• The centre hole on the blade must ﬁt the mandril

and be snugly fastened in place with the proper

washer and lock nut.

WARNING: A loose or off-centre blade can

shatter during use.

• Position material to be cut at 90 degrees to the

blade. Support the other end to prevent the blade

from binding.

• Do not rush cutting. Let the wheel cut without

burning or jamming.

• When cutting is complete, let the blade stop before

moving material.

• Maintain the saw in good repair with the blade guard

in place and working smoothly. Tighten any loose

parts and replace any broken or damaged ones.

• Don’t try to adjust for length on the downward

cutting motion. Your hand could slide into the blade

while it is spinning.

• With some large chop saws (Figure 38-31),

additional precautions are required because of the

tremendous torque the saws can develop.

• Beware of sparks landing on combustible material.

Guard Up Guard Down

CAUTION:

Guard lifted to show blade

for training purposes only.

Figure 38-31: Precautions for Large Chop Saws

POWER TOOLS – SAWS

38-10

Construction Health and Safety Manual

Quick-Cut Saws

Hand-held portable circular cut-off saws

are commonly known as “quick-cut saws” in

construction (Figure 38-32). They are widely used

for cutting concrete, masonry products, sheet

metal products (both steel and aluminum), and

light steel sections such as angles and channels.

Belt Tensioner

Belt Cover

Cutting Arm

Throttle

Trigger

Throttle

Trigger

Lockout

Throttle Latch

Cylinder Cover

Cover/Preﬁlter

Mufﬂer

Front Handle

Cutting Disk

Disk

Guard

Knob for

Guard

Preﬁlter

Starter

Handle

Stop

Switch

Choke

Rear Handle

Adjustment Screws,

Carburetor

Fuel Tank

Starter

Handle

Figure 38-32: Quick-Cut Saws

Hazards

Quick-cut saws are high-powered as compared

to similar tools. Hazards include high-speed blade

rotation, blade exposure during operation, and

exhaust from the internal combustion engine (the

usual power source).

The saws also create clouds of dust when dry-

cutting masonry and showers of hot sparks when

cutting metal products, especially steel.

These hazards can result in cuts, kickbacks,

exposure to carbon monoxide fumes, exposure to

dusts (silica from concrete and masonry products

in particular), burns, ﬂying particles hitting the eye,

and other injuries from ﬂying material when work is

not secured for cutting or when blades ﬂy apart.

These hazards can be controlled by:

• Training operators to use quick-cut saws properly

and to wear the right protective equipment such

as eye, hearing, and respiratory protection as well

as face shields and gloves

• Keeping saws in good working condition,

equipping them with proper blades or disks, and

using them with all guards in place

• Securing work to keep it from shifting during cutting

• Being cautious around sharp edges left by cuts.

Training

Operators should be instructed in the care,

maintenance, and operation of quick-cut saws.

They should read the operating manual, review the

major points, and receive both oral and written

instruction.

The operating manual should be available on the

job, not only for instruction but also for ready

reference if something goes wrong with the saw

or it must be used for work outside the operator’s

experience.

Time spent on instruction will reduce accidents

and injuries as well as prolong the service life of

the saw. As a minimum, the operator should be

instructed in the following:

• Caring for the saw

• Installing disks and blades

• Mixing fuel and fueling the saw

• Starting the saw

• Supporting and securing work to be cut

• Maintaining proper cutting stance and grip

• Using proper cutting techniques for different

material

• Wearing respiratory protection against dusts

• Learning how to inspect and store abrasive disks.

Care

Quick-cut saws must be serviced and maintained

in accordance with the manufacturers’ instructions.

Replacement parts should be those recommended

by the manufacturer.

Cracked, broken, or worn parts should be replaced

before the saw is used again. Guards and air intakes

should be cleaned regularly and often. Abrasive

disks should be checked before installation and

frequently during use. Correct any excessive blade

vibration by replacing the cutting blade before

trying to make a cut.

In conﬁned areas, make sure that ventilation is

adequate. Gasoline-driven saws release carbon

monoxide (CO) gas, which is odourless, colourless,

and highly toxic. Section 47 of the Construction

Projects regulation (213/91) requires that the air be

tested for CO buildup when fuel-ﬁred devices are

being used in a conﬁned space. Make sure a written

test strategy is in place. Also, make sure you know

what a CO alarm sounds like and what actions to

take if the alarm sounds.

POWER TOOLS – SAWS

Tools and Techniques

38-11

Starting

Most of the following procedures are for gasoline-

powered quick-cut saws—the type most commonly

used in construction.

• Use caution when preparing the oil/gasoline

mixture and when fuelling the saw. No smoking

or ignition sources should be allowed in the area

where fuel is mixed or tanks are ﬁlled.

• Fill the tank outdoors in a well-ventilated space

at least 3 metres from the area where the saw will

be used. Spilled fuel should be wiped off the saw.

• Avoid fuelling the saw on or near formwork.

Gasoline spills are a ﬁre hazard. Use a funnel to

avoid spills.

• Do not overﬁll the saw or run it without securing

the fuel tank cap. Gasoline seeping from the tank

can saturate your clothing and be ignited by

sparks thrown off from metal cutting. The only

cap to use is one supplied by the manufacturer.

• Check the saw for leaks. Sometimes vibration

makes gas lines leak.

• Start the saw in an area clear of people and

obstacles. Under no circumstances should anyone

be standing in front of the saw as it starts or

while it’s running.

• Put the saw on a smooth hard surface for

starting. The guard should be properly set for the

type of cut beforehand.

• Assume a solid well-balanced stance. Do not

wrap the starter cord around your hand—this can

cause injury.

• Set one foot on the rear handle, put one hand on

the top handle to lift the blade off the surface,

and use the other hand to pull the starter cord

(Figure 38-33).

Figure 38-33: Starting Position

• Once the saw is running, release the throttle and

make sure the engine drops to idle without the

disk or blade moving.

• Run the engine at full throttle and let the disk

or blade run freely to make sure it turns on the

arbor without wobbling or vibrating.

WARNING: Always shut off saw before fuelling.

Keep fuel container well clear of work area.

Support

One of the major hazards with quick-cut saws is

failure to support and secure the work to be cut.

The saw is powerful enough to throw material around

unless it is securely held and supported. Standing on

material to hold it down is not recommended.

For repeated cuts of masonry or metal pieces, a

jig is ideal for efﬁciency and safety. The jig should

be designed and built to hold material in place

after measurement without further manual contact

(Figure 38-34).

Figure 38-34: Jig for Cutting

Stance and Grip

The quick-cut saw is a heavy, powerful tool that

must be held by hand. Operators need a secure

stance with legs apart for balance and support.

The saw should be held at a comfortable, balanced

location in front of the operator.

Grip the saw ﬁrmly with one hand on each handle.

Hold your forward arm straight to keep the saw from

kicking back or climbing out of the cut (Figure 38-35).

Figure 38-35: Cutting Stance and Grip

POWER TOOLS – SAWS

38-12

Construction Health and Safety Manual

Cutting

Although skill in handling the quick-cut saw

can only be learned through practice, some

safety considerations and operating techniques

must always be kept in mind, even by the most

experienced operators.

Work should be supported so that the disk or blade

will not bind in the cut. Support heavy materials on

both sides of the cut so the cut piece will not drop

or roll onto the operator’s foot. Light materials can

generally be allowed to fall. In all cases, the cut

should be as close as possible to the supporting

surface (Figure 38-36).

Saw will bind. Heavy Material

Saw should not bind.

Light Material

Figure 38-36: Support for Dierent Cuts

Kickback and Pull-In

Kickback can happen extremely fast and with

tremendous power. If the segment of the disk or

blade shown in Figure 38-37 contacts the work, the

disk or blade starts to climb out of the cut and can

throw the saw up and back toward the operator

with great force.

Figure 38-37: Kickback

For cutting, keep the throttle wide open. Ease the

blade down onto the cut line. Don’t drop or jam the

blade down hard. Move the saw slowly back and

forth in the cut.

Hold the saw so that disk or blade is at right angles

to the work and use only the cutting edge of the

disk or blade (Figure 38-38). Never use the side of

a disk for cutting. A worn disk will almost certainly

shatter and may cause severe injury.

Figure 38-38: Saw at Right Angles to Material

Beware of blade run-on. The blade may continue

to rotate after the cut and run away with a saw set

down too soon.

Don’t force the saw to one side of the cut. This

will bend the disk or blade and cause it to bind,

possibly to break.

Water cooling is recommended for cutting masonry

materials. It prolongs disk life and reduces dust

exposure.

Keep pressure on the saw reasonably light.

Although more pressure may be necessary for hard

materials, it can cause an abrasive disk to chip or

go “out of round.” This in turn will make the saw

vibrate. If lowering the feed pressure does not stop

the vibration, replace the disk.

Don’t carry the saw any distance with the engine

running. Stop the engine and carry the saw with

the mufﬂer away from you.

To avoid kickback, take the following steps:

• Secure and support the material at a comfortable

position for cutting. Make sure that material will

not move, shift, or pinch the blade or disk during

cutting.

• Keep steady balance and solid footing when

making a cut.

• Do not support the work on or against your foot

or leg.

• Use both hands to control the saw. Maintain a

ﬁrm grip with thumb and ﬁngers encircling the

handles.

• Never let the upper quarter segment of blade or

disk contact the material.

• Run the saw at full throttle.

• Do not cut above chest height.

• When reentering a cut, do so without causing the

blade or disk to pinch.

Pull-in occurs when the lower part of the disk or

blade is stopped suddenly—for instance, by a cut

closing up and binding. The saw pitches forward

and can pull the operator off balance.

POWER TOOLS – SAWS

Tools and Techniques

38-13

Protective Equipment

In addition to the standard equipment mandatory

on construction sites, operators of quick-cut

saws should wear snug-ﬁtting clothing, hearing

protection, eye and face protection, and heavy-

duty leather gloves (Figure 38-39).

Hard Hat

Eye Protection

Hearing

Protection

Face Shield

Heavy-Duty

Non-Slip Gloves

Leg Protection

(for sparks)

Grade 1 Boots

with Non-Skid

Soles

Figure 38-39: Protective Equipment

The dry cutting of masonry or concrete products calls

for respiratory protection as well. (See the chapters

on personal protective equipment in this manual.)

For general dust hazards, a half-mask cartridge

respirator with NIOSH-approval for dust, mist, and

fumes should provide adequate protection when

properly test-ﬁtted and worn by a cleanshaven person.

Disks and Blades

Disks and blades are available in three basic types:

1. Abrasive disks

2. Diamond-tipped blades

3. Carbide-tipped blades.

Use only the disks and blades compatible with your

saw and rated for its maximum rpm (Table 38-2).

Blades or disks may ﬂy apart if their rpm is not

matched to saw rpm. If you have any doubts, consult

the operating manual or a reputable supplier.

Table 38-2: Disk Types and Uses

Type Uses Materials

Concrete All-around use,

most economical

for cutting concrete

and masonry.

Water-

cooling recommended

to increase disk life and

reduce dust.

Concrete,

stone, masonry

products, cast iron,

aluminum, copper,

brass, cables, hard

rubber, plastics.

Metal Primarily for steel,

not suited for

masonry products.

Water-cooling is not

recommended with

metal abrasive disks.

Steel, steel alloys,

other hard metals

such as cast iron.

Diamond

Abrasive

Disk

Cuts faster than

other abrasive disks

and creates less

dust.

Water-cooling is

absolutely necessary

to prevent heat build-

up that can make disk

disintegrate.

Stone, all masonry

and concrete

products. Not

recommended for

metals.

Dry-Cut

Diamond

Blade

Fast cuts, lots of dust,

very expensive. Let

blade cool for 10–15

seconds every 40–60

seconds. Continuous

cutting will damage

the blade.

Stone, all masonry

and concrete

products. Not

recommended for

metals.

Diamond Disks and Blades

Diamond disks are normally used with water

cooling. They are now available for dry cutting,

which may be necessary to avoid staining some

masonry products.

When dry-cutting with a diamond blade, let the blade

cool for 10–15 seconds every 40–60 seconds. This can

be done simply by pulling the saw out of the cut.

Carbide-Tipped Blades

These blades must be used with care. If a carbide-

tipped blade encounters material harder than what

it is designed to cut, the tips may ﬂy off.

A carbide-tipped blade used with a quick-cut saw

must be designed for that purpose. It must also

be used only to cut the materials speciﬁed by the

manufacturer.

Inspection/Installation

Inspect disks and blades before installing them.

• Make sure that contact surfaces are ﬂat, run true

on the arbor, and are free of foreign material.

• Check that ﬂanges are the correct size and not

warped or sprung (Figure 38-40).

POWER TOOLS – SAWS

38-14

Construction Health and Safety Manual

• Check the label to make sure that the disk or

blade is approved for use on high-speed quick-

cut saws and has a rated rpm suitable to the saw

being used. A periodic service check may be

necessary to ensure that the rpm still meets the

manufacturer’s requirement.

• Inspect the disk or blade for damage. Abrasive

disks tapped lightly with a piece of wood should

ring true. If the sound is dull or ﬂat, the disk is

damaged and should be discarded.

• Make sure that diamond or carbide tips are all

in place. Do not use diamond or carbide-tipped

blades or disks if any tips are missing.

• Do not drop abrasive disks. Discard any disk that

has been dropped.

• Use the proper bushing on the arbor so that the disk

runs true on the shaft without wobbling or vibrating.

• Discard badly worn disks that are uneven or “out

of round.”

Figure 38-40: Check Disk for Warping

Table Saws

The table saw most often used in construction

is the 10-inch belt-driven tilting arbor saw. The

dimension refers to the diameter of the saw blade

recommended by the manufacturer.

Although some saws are direct-drive (Figure

38-41), with the blade mounted right on the motor

arbor, most are belt-driven (Figure 38-42).

Figure 38-41: Direct-Drive Table Saw

Figure 38-42: Belt-Driven Table Saw

Both types are equipped with a ﬁxed table top and

an arbor that can be raised, lowered, or tilted to

one side for cutting at different depths and angles.

Basket Guards

Basket guards may be fastened to the splitter or

hinged to either side of the saw on an L-shaped or

S-shaped arm (Figure 38-43).

Basket Guard

Hinged to Arm

Basket

Guard

Fastened

to Splitter

Figure 38-43: Basket Guards

Basket guards can protect the operator from

sawdust, splinters, and accidental contact with the

blade. Keep the basket guard in place for normal

operations such as straight and bevel ripping

and mitre cutting. When the guard is removed to

permit cutting of tenons, ﬁnger joints, rabbets,

and similar work, use accessories such as feather

boards, holding jigs, push sticks, and saw covers.

It should be noted that safety regulations do not

permit removing a guard. To be in compliance,

procedures must be in place to provide equal or

better protection to workers using the saw.

Figure 38-44 shows a split basket guard with

a see-through cover. One side can be moved

sideways for a blade tilted to 45 degrees. One

side can be lifted up while the other remains as a

protective cover.

Figure 38-44: See-Through Plastic Basket Guard

Sheet metal baskets fastened to the splitter are

less effective because the operator cannot see the

saw blade.

Kickback

Kickback occurs when stock binds against the saw

blade. The blade can ﬁre the wood back at the

operator with tremendous force, causing major

injuries to abdomen, legs, and hands.

POWER TOOLS – SAWS

Tools and Techniques

38-15

• Never stand directly behind the blade when

cutting. Stand to one side. See that other workers

stand clear as well.

• Make sure the rip fence is aligned for slightly

more clearance behind the blade than in front.

This will help prevent binding.

• Use a sharp blade with teeth properly set for the

wood being cut. A dull or badly gummed blade

will cause friction, overheating, and binding.

• Install a splitter to keep the kerf (cut) open

behind the blade. Also effective are anti-kickback

ﬁngers attached to the splitter.

Splitters

Splitters prevent the kerf from closing directly

behind the blade. Ideally, they should be slightly

thinner than the saw blade and manufactured from

high tensile steel.

Splitters are not always needed with carbide-tipped

saw blades, whose relatively wide kerf may provide

the desirable clearance. A wide kerf alone, however,

is often not enough to keep some boards from

closing behind the cut and binding against the blade.

In general, it is impossible to predict how a board

will behave during ripping. It may remain straight,

presenting no problems. On the other hand, the

release of internal stresses may make the two

ripped portions behind the blade either close up or

spread apart.

Figure 38-45 shows a disappearing splitter with

anti-kickback ﬁngers. It can be pushed down when

in the way of a workpiece and pulled up when

necessary after the machine has been shut off.

Figure 38-45: Disappearing Splitter

with Anti-Kickback Fingers

Roller Stand

Operators risk injury trying to maintain control over

long pieces of stock singlehandedly, especially if the

stock begins to bind on the blade and kick back.

A roller stand (Figure 38-46) provides the needed

support. Adjust it to a height slightly lower than the

saw table to allow for sagging of the material. Be

sure to set up the stand so the roller axis is at 90

degrees to the blade. Otherwise, the roller could

pull the stock off to one side and cause binding.

Figure 38-46: Roller Stand

Whatever the design, a support stand should

be standard equipment in every carpentry and

millwork shop. It can be used as an extension to a

workbench, jointer, or bandsaw and is especially

important with the table saw.

Extensions

Made of wood or metal, table top extensions

installed behind and to both sides of the machine

can make the cutting of large sheets of plywood

and long stock safer and more efﬁcient.

In most cases, a space must be provided between

the extension and saw top for adjusting the basket

guard and allowing scrap to fall clear.

Blades

Table saw blades are similar to those for circular

saws. The teeth on carbide-tipped, hollow-ground,

and taper blades do not need setting (Figure

38-47).

Cutting Teeth

Expansion Slot

Raker Tooth

Raker Gullet

Gullet

Carbide Tip

Shoulder

Combination Carbide Blade

Straight

Top Raker

Tooth

Bevel

Top Cutting

Tooth

Standard Thin

Rim

Hollow

Ground

Figure 38-47: Carbide-Tipped Blades

Blade Adjustment

Proper adjustment of cutting depth holds blade

friction to a minimum, removes sawdust from the

cut, and results in cool cutting.

Sharp blades with properly set teeth will keep the

work from binding and the blade from overheating

and kicking back.

POWER TOOLS – SAWS

38-16

Construction Health and Safety Manual

The blade should project the depth of one full

tooth above the material to be cut. When using

carbide-tipped blades or mitre blades, let only half

a tooth project above the material.

Blade Speed

The right cutting speed is important. The blade

should turn at the correct rpm to yield the

recommended cutting speed.

When not in motion, saw blades, especially large

blades, are usually not perfectly ﬂat because of

internal tensions. At the right operating speeds,

however, the blades straighten out as a result of

centrifugal force and cut smoothly at full capacity.

Blades running too fast or too slow tend to start

wobbling either before or during a cut. If cutting

continues, the blade will overheat and may kick

back, damaging the equipment, and injuring the

operator.

Rip Fence

The rip fence is used mainly to guide the stock and

maintain correct width of cut. The fence on small

saws is usually clamped down at both the front

and back of the table by pushing down a lever or

turning a knob. Adjust the fence slightly wider at

the back to let the wood spread out behind the cut

and reduce the risk of kickback.

Many carpenters add a piece of hardwood to the

rip fence in order to rip thin pieces of wood and

make dadoes and rabbets. The auxiliary fence

can be set close to the cutters without the risk of

contact between the blade and the steel fence.

Pushsticks

Narrow pieces can be cut safely and efﬁciently with

the help of pushsticks (Figure 38-48), which should

be painted or otherwise marked to prevent loss.

Figure 38-48: Pushsticks

To rip narrow, short pieces, a push block is the

right choice (Figure 38-49). The shoe holds the

material down on the table while the heel moves

the stock forward and keeps it from kicking back.

Figure 38-49: Push Block

Different designs of pushsticks are required for

cutting different kinds of stock.

The heel of the pushstick should be deep enough

to prevent it from slipping and strong enough to

feed the stock through the saw.

Feather Boards

You can also use one or two feather boards (Figure

38-50) to rip narrow stock safely. A feather board

clamped immediately in front of the saw blade will

provide side pressure to the stock without causing

binding and kickback. Use a push block to feed

stock all the way through.

Clamp

second

feather

board to

auxiliary rip

fence.

Clamp feather

board in front

of saw blade.

Figure 38-50: Feather Boards

Operation

• Follow Basic Saw Safety (at the beginning of this

chapter).

• Keep the ﬂoor around the saw clear of scrap and

sawdust to prevent slipping and tripping.

• Always stop the machine before making

adjustments. Before making major adjustments,

always disconnect the main power supply.

• Select a sharp blade that is suitable for the job.

• Use the safety devices such as pushsticks and

feather boards recommended in this chapter.

• Make sure nobody stands in line with a revolving

blade.

• Don’t let anyone or anything distract you when

you are operating the saw.

• Whenever possible, keep your ﬁngers folded in a

ﬁst rather than extended as you feed work into

the saw.

• Follow the manufacturer’s recommendations

in matching the motor size to the saw.

Underpowered saws can be unsafe.

POWER TOOLS – SAWS

Tools and Techniques

38-17

• Never reach around, over, or behind a running

blade to control the stock.

• Table saws should be properly grounded. Check

the power supply for ground and always use a

ground fault circuit interrupter. This is mandatory

for saws used outdoors or in wet locations.

• Table saws must be equipped with an on/off

switch so power can be shut off quickly in an

emergency.

• A magnetic starter switch is preferable to a

mechanical toggle because it prevents the saw

from starting up again unexpectedly after an

interruption in power.

• When purchasing a new table saw, try to get one

equipped with an electric brake. The brake stops

the blade rotation within seconds of the operator

turning off the saw. The reduced risk of injury is

worth the extra cost.

• Extension cords should be of sufﬁcient wire

gauge for the voltage and amperage required by

the saw and for the length of the run.

Radial Arm Saws

The motor and blade of the radial arm saw are

suspended above the table (Figure 38-51). Because

the motor and blade assembly can be locked in

different positions and can travel during the cut,

the operator must pay special attention to keeping

ﬁngers and hands clear.

OFF Button

Rip Scale

Rip Pointer

Rip Lock

Column

Yoke Clamp

Handle

Right-Hand

Motor Arbor

Motor

Key

Switch

Dust Spout

Yoke

Bevel Scale

Fence

Figure 38-51: Radial Arm Saw

Injuries involving radial arm saws tend to be

serious. By using appropriate guards and

procedures, however, operators can safely use the

saw for crosscuts, mitre cuts, ripping, and dadoes.

Set-Up

• The saw must be adequately powered for the

work, especially for cutting thick hardwood.

• The saw should be installed in a well-lit area out

of the way of trafﬁc, with enough space to store

and handle long lengths of wood. Locating the

machine with its back to a wall or partition can

help to keep ﬂying pieces from hitting anyone.

• Where possible, mark the ﬂoor with yellow warning

lines to keep other personnel back from the saw.

• Make sure all safety guards and devices are in

place.

• Choose the right blade for the job. A sharp

tungsten carbide combination blade is good for

both crosscutting and ripping without frequent

resharpening. For information on blade types and

uses, refer to earlier sections of this chapter.

Ripping and Crosscutting

• For regular ripping, turn the motor away from the

column to the in-rip position. Feed stock into the

saw from the right side.

• To cut wide stock, change the saw to the out-rip

position. Feed stock into the saw from the left side.

Operators accustomed to in-ripping may ﬁnd this

set-up awkward. Remember—the blade must turn

up and toward the person feeding the stock.

• Do not force the cut. Allow the blade through the

wood at its own pace.

• To avoid kickback, take the following precautions.

- Maintain proper alignment of blade with fence.

- Adjust anti-kickback device (Figure 38-52) to

1/8 inch below the surface of stock being fed.

- Use a sharp blade, free of gum deposits and

with teeth properly set.

- When binding occurs, stop saw and open kerf

with a wedge.

- After completing cut, remove stock from

rotating blade to prevent overheating and

possible kickback.

- Always push stock all the way through past the

blade.

- Do not leave machine with motor running.

- Use a push stick when ripping narrow pieces.

Have suitably sized and shaped pushsticks for

other jobs as well.

See information on pushsticks and feather boards

under Table Saws, earlier in this chapter.

General Procedures

• Follow Basic Saw Safety (at the beginning of this

chapter).

• If you don’t have someone to help with long

stock, use a roller stand or extension table to

support the work.

• Always return the motor head to the column stop.

• When crosscutting or mitring, keep hands at least

six inches away from the blade. Do not adjust the

length of cut until the motor is back at column.

POWER TOOLS – SAWS

38-18

Construction Health and Safety Manual

• Slope the table top back slightly to keep the

blade at the column, thereby preventing contact

with stock being placed in position.

• Do not allow the blade to cut too quickly when

crosscutting or mitring.

• Avoid drawing the blade completely out of the

cut. The cut piece, whether large or small, often

moves. When the saw is rolled back towards the

column, the teeth can grab the piece and shoot it

in any direction.

• Do not cut by pushing the saw away from you

into the stock. The material can lift up and ﬂy

over the fence.

Figure 38-52: Anti-Kickback Device

Jigs

The control provided by a well-made jig is essential

for making irregular cuts safely and accurately.

Keep commonly used jigs (Figure 38-53) on hand.

Jigs such as those for making stair and doorframe

wedges and tapers are designed to carry stock past

the blade with the saw locked in the rip position.

Taper Jig

Tenoning Jig

Figure 38-53: Jigs

When you’re drawing the saw into the stock, clamp

or nail jigs to the table to prevent slipping.

Re-Sawing with Blade Horizontal

The rip fence on the radial arm saw is too low

for supporting material to be re-sawn on edge.

Therefore the material must be laid ﬂat on the

table and the motor must be turned so the blade

is parallel to the table. The closeness of the arbor

requires an auxiliary table top and fence to re-saw

thin stock.

Because the kickback fence can’t be used and

controlling stock is sometimes difﬁcult, re-sawing

on the radial arm saw can be hazardous.

If no other equipment is available, rip the stock

halfway through, then turn it around and complete

the cut.

On the second cut, be sure to push the two halves

well past the blade once they have been cut apart.

Pushsticks and featherboards clamped to the table

can reduce hazards.

Dadoes

A dado head is an essential tool for cutting

grooves, rabbets, and dadoes. A groove is cut with

the grain; a dado is cut across the grain; and a

rabbet is a shoulder cut along the edge of a board.

The most common dado head consists of two

outside cutters and several inside chippers between

the outside cutters (Figure 38-54).

Figure 38-54: Dado Head Cutter

Blades and Chippers

Another type is sometimes called a quick-set dado,

consisting of four tapered washers and a blade. By

rotating the locking washers, the blade will oscillate

and cut a groove to the desired width.

Because of their small size, dado heads do not run

at the peripheral feed speed on a big radial arm saw.

As a result, the blade feeds itself too fast, either

stopping the motor or lifting the work and throwing

it back. To prevent this, make several light passes,

lowering the dado head 1/8 to 1/4 inch each time.

Dado heads require guards for safety. Always

make sure guards are in place before starting work.

Proper rotation of the teeth is up and toward you.

Other Accessories

Rotary accessories of various types are advertised

as turning the radial arm saw into a multifunction

machine. Operators should remember that the saw

has its limitations. Possible problems include the

following.

• Shaper heads run too slow for safe and smooth

work.

• Grinding stones may run too fast or slow and are

not recommended.

• Sanding drums tend to run too fast and may burn

the wood.

POWER TOOLS – SAWS