Transcript Portable Power Tools - Biosystems and Agricultural Engineering

Portable Power Tools
Unit 14
Page 180
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Introduction
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Portable Power Tool: A tool that can be held in the operators
hands, but is not hand powered.
Four common sources of power.
Battery
Electricity
Pneumatic
There are advantages and disadvantages
for each type of power source.
Engine
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1. Electrical Power
• Very popular
• Usually use 120 V, 1ø power
Disadvantages
– Must stay connected to
power cord.
– Hazards of electricity
Advantages
– Unlimited power
– Many different types of
tools.
Extension cord must be
proper size and in good
condition.
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2. Pneumatic
Becoming more popular where compressed air is available.
Advantages
– Smaller dimensions for torque
produced
– Torque easily adjusted
(changing pressure)
– Popular in hazardous
environments
Disadvantages
• Air must be clean and dry.
• A blast of high pressure air can
embed objects in the skin or
eyes.
• Air hose more difficult to
manage than electric cord.
All common tools can be air driven.
– Drills
– Ratchet drives
– Sanders
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3. Battery
New technology in batteries has made battery powered tools the
first choice for most professionals.
Advantages
– Portability
– Sealed unit
– No electrical circuit
hazards.
– Can be used with a wider
variety of tools when
compared to pneumatic.
Disadvantages
– May be less torque
– Must have a charged battery
to use.
– Batteries can have a short
useable life and are
expensive to replace.
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4. Engine
Popularity is gaining with the resent invention of lighter weigh engines.
The elimination of 2-cycle engines will require a redesign.
Advantages
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Portability
No air hose
No extension cords
No battery
Disadvantages
– Must be used in open
environment.
– Disadvantage of engine
maintenance.
– Safety concerns of gas
engines.
– Usually only large sizes.
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Portable Power Tool Safety
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Use GFCI protected circuit.
Use three-wire electrical source if tool housing is metal or partially
metal and not double insulated.
Insure blades, bits, and other cutting devices are clean and sharp
Support work carefully
Keep all tools clean and free of dirt.
Keep tool vent holes clean.
Wear appropriate personal protection
Avoid or use extra care when working in wet areas
Do not force tools to work.
Hold power tool firmly and insure your have control at all times.
If the condition of the tool is in doubt, do not use.
Announce to co-workers before starting a tool.
Lay tool down correctly
Take any faulty tools out of use and insure they are fixed before
returning.
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Nail Guns
• Popular because they are fast and
efficient.
– Produce enough force to drive 2 - 3
inch nail into dense wood.
– Accelerate nail to 1,000 feet per
second.
• Four types
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Brad
Framing
Finishing
Staple
• Power
– Pneumatic
– Electric
– Fuel cell
• Fasteners
– 1/4 inch brad and staples up to 4
inch nails.
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Portable Drills
• Size
– Size based on capacity of chuck
– Wattage difference within chuck
size
– Common sizes are 1/4, 3/8, 1/2 &
3/4 inch
• Construction
– Case will be metal, non-metallic
or a combination.
– Wide variety
• Options
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Variable speed
Reversing
Extra handle
Hammer action
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Torque clutch
Depth stop
Drill press attachment
Keyless chuck
Screw chuck
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Portable Drill-cont.
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Use many different types of bits.,
Drill holes and slots
Use to drive screws
Sanding disc and wire wheels can be
used.
– Must be careful to not exceed the duty
cycle
Always center punch location of hole.
Drill pilot hole before using a large drill bit.
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Portable Drill Safety
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Inspect bit before using
Tight chuck using more that one hole
Center punch metal before starting to drill
Hold material securely
Do not exceed rpm of bit
Use even pressure
Ease off pressure when drill starts to break through
Don’t bind the drill bit
Stand in a balanced position
Remove the drill from the chuck when finished
Store portable drill and bits in case or designated storage rack.
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Sander
• Three common types
– Belt
– Disc
– Pad
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Sander-cont.
• Portable power sanders to the same job as hand sanding--just
faster.
• Normally sand with the grain
• Exceptions
– Uneven boards
– Rough surface
– Removing difficult finishes
• Different grit paper available
– Coarse grit = rapid sanding, rough surface
– Fine grit = slow sanding, smooth surface
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Belt Sander
• Very versatile
 Popular for rough sanding
because of aggressive
action with coarse belts.
 Can produce smooth finish
with fine belt.
• Some belts are not bidirectional.
• Dust collection system
highly recommenced.
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Belt Sander Safety
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Wear appropriate PPE
Check cords and switches
Install appropriate belt for the desired cutting action and finish
Lay sander on side when not in use
Empty dust bag frequently
Always start sander above the surface
Use two hands at all times
Keep machine in motion
Lift off material while still running
Never sand on the drums
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Disc Sander
• Machine can use
sanding disc,
grinding wheel
and wire brush
interchangeably.
• Must follow
manufacturer's
recommendation
for use.
Switch Lock
Power Cord
Motor Housing
Tool Rest
Sanding
Wheel
Sanding
Disc
Handle
Switch
Vents
Handle
Guard
• Several tools with this right angle design look the same.
• Some are sanders, some are sanders/grinders and some are
grinders.
• Big difference in construction
• Grinders are much heavier construction.
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Disc Sander Safety
• Select the sanding wheel appropriate for the material being
sanded.
– Aluminum oxide = wood or metal
– Flint paper = wood only
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Use the appropriate guard
Wear appropriate PPE.
Grip machine firmly in both hands before starting
Do not force the machine to work
Lay the machine on the tool rest, not the disc.
Be aware of, and plan for the direction of material being
discharged by the wheel.
• Hold small pieces in a vise.
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Disc Grinder Safety
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Wear face shield plus safety glasses.
Check grinding wheel for cracks before using
Only use wheel designed for that machine.
Never use grinding wheel that is less than 1/2 original diameter.
Secure small pieces in a vise
Do grind near combustibles
Hold the machine with both hands at all times.
Always be aware of were the discharged sparks and grit is
going.
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Pad (Finishing) Sander
Motor Housing
Switch Lock
Handle
Power
Cord
Handle
Paper
Clamp
Switch
Sand
Paper
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Pad
Multiple pad movements possible.
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Paper
Clamp
Reciprocating
Circular
Orbital
Random
Slower cutting
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Pad Sander Safety
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Use appropriate PPE.
Use correct size of paper.
Disconnect power when changing paper.
Only use light pressure when sanding
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Portable Saws
• Portable saws can be divided into three categories.
– Sabre
– Reciprocating
– Circular
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Sabre Saws
Switch
Handle
Motor
Housing
Blade
Retention
Screw
Toe
Power
Cord
Base Tilt
Lock
Blade
Base
• A compact saw that is
very useful for cutting
curves.
• Designed for wood,
but will cut thin metal.
• Blade uses
reciprocating motion.
• Can be used for blind
cuts.
• Base may tilt for
cutting bevels.
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Sabre Saw Safety
• Wear appropriate PPE
• Select correct blade for job.
– Width of blade determines minimum radius
• Secure material being cut
• Let saw determine feed rate.
• Must maintain downward pressure on the saw when cutting.
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Reciprocating Saw
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Motor Housing
Usually heavier
Shoe
duty that the
sabre saw.
Longer stroke
on the blade.
Blade
Many different
Blade
types of blades.
Retention
Screw
Designed for
wood and
metal.
Does not cut as precise as sabre saw.
May be multiple speed.
Can be used to make a blind cut.
Very popular for demolition work.
Switch
Switch
Lock
Handle
Cord
Vents
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Reciprocating Saw Safety
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Wear appropriate PPE.
Select the correct blade for the job.
Select the correct speed.
Be careful not to bind, pinch or crowd the blade.
Hold the shoe against the work at all times.
Do not wear loose fitting clothing.
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Circular Saw
• Most popular saw for
carpentry work.
• Different size and
types of blades are
available.
• Can be used for wood
and metal.
• Available in direct
mount, right and left
hand and worm drive.
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Circular Saw Safety
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Wear appropriate PPE.
Use face shield + safety glasses
Use blade appropriate for work.
Support work correctly.
Disconnect the power when adjusting the saw.
Adjust blade for depth so that only 1/4 inch or the depth of one
tooth extends through the work.
Hold saw in both hands.
Start the saw before contacting work.
If the saw stalls, back out of kerf.
Watch the line ahead of the saw.
Near the end of the cut reduce the pressure.
For ripping use the ripping guide attachment or clamp a straight
edge to the work.
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Circular Saw Capacity
• Capacity of portable circular saws at 45 degree bevel and
straight.
BLADE DIAMETER
CAPACITY 45
o
CAPACITY 90
4 1/2
1 1/16
1 5/16
6 1/2
1 5/8
2 1/16
6 3/4
1 3/4
2 7/32
7 1/4
1 7/8
2 3/8
7 1/2
2 1/16
2 17/32
8 1/4
2 1/4
2 15/16
10 1/4
2 3/4
3 5/8
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3 5/16
4 3/8
o
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Router
• Routers are used for
specialized jobs such as
ornamental shapes, rabbets,
dadoes, hinges, etc.
• Router bits turn at high
speeds.
• May have several
attachments.
• Must use guide to complete
straight cuts.
• May be mounted on a table.
Cord
Switch
Depth of Cut
Adjustment
Depth of cut
Scale
Handle
Collet
Base
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Router Safety
• Wear appropriate PPE.
• Secure work.
• Insure router is unplugged before installing bit or setting depth
adjustment.
• Always inspect bit for condition and sharpness.
• Install the appropriate bit.
• Insure bit shank is fully inserted into collet.
• Carefully set depth of cut.
• Set base squarely on work.
• Always use both handles
• Feed router into work at correct speed.
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Questions
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