Central Pneumatic Earthquake 92421 User manual

1” EARTHQUAKE
IMPACT WRENCH
ASSEMBLY and OPERATING
INSTRUCTIONS
3491 Mission Oaks Blvd., Camarillo, CA 93011
Visit ourWeb site at http://www.harborfreight.com
For technical questions and replacement parts,please call 1-800-444-3353
Model 92421
®
Copyright©2005 by Harbor Freight Tools®. All rights reserved. No portion of this
manual or any artwork contained herein may be reproduced in any shape or form
without the express written consent of Harbor Freight Tools.
TO PREVENT SERIOUS INJURY,
READ AND UNDERSTAND ALL WARNINGS
AND INSTRUCTIONS BEFORE USE.

Page 2SKU 92421 For technical questions, please call 1-800-444-3353
Specifications
SaveThis Manual
You will need the manual for the safety warnings and precautions, assembly instructions,
operating and maintenance procedures, parts list and diagram. Keep your invoice with this
manual. Write the invoice number on the inside of the front cover. Keep the manual and
invoice in a safe and dry place for future reference.
Safety Warnings and Precautions
WARNING: When using tool, basic safety precautions should always be followed to
reduce the risk of personal injury and damage to equipment.
Read all instructions before using this tool!
1. Keep work area clean. Cluttered areas invite injuries.
2. Observe work area conditions. Do not use machines or power tools in damp or wet
locations. Don’t expose to rain. Keep work area well lighted. Do not use electrically
powered tools in the presence of flammable gases or liquids.
3. Keep children away. Children must never be allowed in the work area. Do not let
them handle machines, tools, extension cords, or air hoses.
4. Store idle equipment. When not in use, tools must be stored in a dry location to
inhibit rust. Always lock up tools and keep out of reach of children.
5. Use the right tool for the job. Do not attempt to force a small tool or
attachment to do the work of a larger industrial tool. There are certain applications for
which this tool was designed. It will do the job better and more safely at the rate for
which it was intended. Do not modify this tool and do not use this tool for a purpose for
which it was not intended.
6. Dress properly. Do not wear loose clothing or jewelry as they can be caught in
moving parts. Protective, electrically nonconductive clothes and nonskid footwear are
recommended when working. Wear restrictive hair covering to contain long hair.
Maximum Torque 1800 Ft. Lbs.
Drive Size 1”
Air Inlet 1/2”-14 NPT
Recommended Air Pressure 90 PSI
Average Air Consumption 8 CFM
Tool Weight 24.6 Lbs.
Impact Mechanism Twin Hammer

Page 3SKU 92421 For technical questions, please call 1-800-444-3353
7. Use eye and ear protection. Always wear ANSI approved impact safety goggles.
Wear a full face shield if you are producing metal filings or wood chips.Wear
an ANSI approved dust mask or respirator when working around metal, wood,
and chemical dusts and mists.
8. Do not overreach. Keep proper footing and balance at all times. Do not reach over or
across running machines or air hoses.
9. Maintain tools with care. Keep tools clean for better and safer performance. Follow
instructions for lubricating and changing accessories. Inspect tool cords and air hoses
periodically and, if damaged, have them repaired by an authorized technician.The
handles must be kept clean, dry, and free from oil and grease at all times.
10. Disconnect air supply.Disconnect air hose when not in use.
11. Remove adjusting keys and wrenches. Check that keys and adjusting wrenches
are removed from the tool or machine work surface before plugging it in.
12. Avoid unintentional starting. Be sure the switch is in the Off position when not in
use and before plugging in. Do not carry any tool with your finger on the trigger,
whether it is plugged in or not.
13. Stay alert. Watch what you are doing, use common sense.Do not operate any tool
when you are tired.
14. Check for damaged parts. Before using any tool, any part that appears damaged
should be carefully checked to determine that it will operate properly and perform its
intended function. Check for alignment and binding of moving parts; any broken parts
or mounting fixtures; and any other condition that may affect proper operation. Any
part that is damaged should be properly repaired or replaced by a qualified technician.
Do not use the tool if any switch does not turn On and Off properly.
15. Guard against electric shock. Prevent body contact with grounded surfaces such as
pipes, radiators, ranges, and refrigerator enclosures.
16. Replacement parts and accessories. When servicing, use only identical
replacement parts.Use of any other parts will void the warranty. Only use accessories
intended for use with this tool. Approved accessories are available from Harbor Freight
Tools.
17. Do not operate tool if under the influence of alcohol or drugs. Read warning
labels if taking prescription medicine to determine if your judgement or reflexes are
impaired while taking drugs. If there is any doubt, do not operate the Impact Wrench.
18. Use proper size and type extension cord. If an extension cord is required, it must be
of the proper size and type to supply the correct current to the compressor without
heating up. Otherwise, the extension cord could melt and catch fire, or cause electrical
damage to the compressor. Check your air compressor’s manual for the appropriate
size cord.
19. Maintenance. For your safety, maintenance should be performed regularly by a
qualified technician.

Page 4SKU 92421 For technical questions, please call 1-800-444-3353
20. Compressed air only. Never use combustible gas as a power source.
21. This Impact Wrench should only be used with impact rated sockets and
extensions. Using any other accessories can cause the accessories to break,
causing permanent damage to the unit and severe injury to the operator.
Note: Performance of the compressor (if powered by line voltage) may vary depending on
variations in local line voltage. Extension cord usage may also affect tool performance.
Warning:The warnings,cautions,and instructions discussed in this instruction manual
cannot cover all possible conditions and situations that may occur. It must be under-
stood by the operator that common sense and caution are factors which cannot be
built into this product, but must be supplied by the operator.
Unpacking
When unpacking, check to make sure that the tool is intact and undamaged.If any parts are
missing or broken, please call Harbor Freight Tools at the number on the cover of this
manual as soon as possible.
For best service you should incorporate an oiler, regulator, and inline filter, as shown in the
diagram above. Hoses, couplers, oilers, regulators, and filters are all available at Harbor
FreightTools. For optimal performance, use an air compressor of 15 Horsepower or more and
limit the total air line length to 30’or less.
1. You will need to prepare a 1/2” air connector (not included) to connect to the Air Inlet
(10B) on the Impact Wrench. First, wrap the 1/2” air connector with pipe thread seal
tape before threading it into the Air Inlet (10B). Connect the 1/2”(or more) ID air source
hose to a quick connect coupler (not included), and then to the ImpactWrench.
Note: Ifyouare not using an automatic oiler system,beforeoperation, adda fewdrops
of Pneumatic Tool Oil to the airline connection. Add a few drops more after each hour
of continual use.
2. Set the air pressure on the regulator to 90 PSI. Do not exceed the recommended air
pressure of 90 PSI.
3. Check the air connection for leaks. Disconnect from the air source.
Impact
Wrench
Air Connection

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Air Inlet (10B)
Forward/Reverse Valve (17)
Side Handle (45)
Screw (46) and
Washer (46A)
Anvil (38)
FIGURE 2
Assembly
Place the Handle (45) onto the side of the Hammer Case (43) and secure it with four Screws
(46) and Washers (46A). See FIGURE 1.
Operation
Warning!! This ImpactWrench supplies powerful torque and is designed to be operated with
two hands. Failure to operate the Impact Wrench with two hands may result in serious, per-
manent injury. See FIGURE 3 below.
Trigger (13)
FIGURE 1
Securing with
Screws (46) and
Washers (46A)
(HexWrench not included)
FIGURE 3
Proper way
to hold the
Impact Wrench

Page 6SKU 92421 For technical questions, please call 1-800-444-3353
Operation (continued)
Refer to FIGURES 2 and 3on page 5, and the Assembly Drawing on page 9.
Note: Turn off your air compressor and disconnect the air hose when you are changing
sockets. After you attach the socket, attach the air hose and turn the air compressor
on.
1. Select the appropriate size 1” drive socket for your needs.
2. Push and snap the socket (not included) onto the Anvil (38).
3. To operate the Forward/Reverse Valve (17) follow the directions in FIGURE 4 below.
FIGURE 4 Forward
Reverse
The Forward/Reverse Valve (17) has
three forward and three reverse speeds.
Turn the Valve to the right toward the
clockwise arrow to tighten, and to the
left, toward the counterclockwise
arrow to loosen. Handle
Tightening
Note: Set the Forward/Reverse Valve (17) so that the anvil turns clockwise (forward).
7. Tighten the nut as tight as you can by hand.
8. Place the socket (not included) over the nut you wish to tighten.
9. Grip the Impact Wrench firmly with two hands and gently squeeze the Trigger (13).
Note: If the Impact Wrench cannot tighten the nut to your satisfaction, do not raise the air
pressure on the compressor over 90 PSI. Pressures above 90 PSI will strip the work-
piece and damage the tool, potentially causing the tool to fail, causing serious injury.
Use other appropriate methods and tools to tighten the nut.
10. When the nut is tightened, release the Trigger (13). Turn off the air compressor and
disconnect the hose.
11. Always check the recommended torque specification for the nut. Use a torque
wrench to tighten the nut to the proper setting after using the Impact Wrench.
(Shown without protective coating for clarity.)

Page 7SKU 92421 For technical questions, please call 1-800-444-3353
Operation (continued)
Loosening
Note: Set the Forward/ReverseValve (17) so that the anvil turns counterclockwise (reverse).
12. Place the socket (not included) over the nut you wish to loosen.
13. Grip the Impact Wrench firmly with two hands and gently squeeze theTrigger (13).
Note: If the Impact Wrench cannot loosen the nut, do not raise the air pressure on the
compressor over 90 PSI. Do not attempt to loosen the nut with the Impact Wrench.
Use other appropriate methods and tools to loosen the nut.
14. When the nut is loosened, release the Trigger (13). Turn off the air compressor and
disconnect the hose.
15. If needed, remove the nut from the socket.
Maintenance
1. Make sure your Impact Wrench is disconnected from the air hose before attempting
any maintenance.
2. Wipe the Impact Wrench down with a lint-free cloth after each use.
3. Make sure the Anvil (38) is clear of dirt or debris. If possible, spray it with compressed
air before each use.
4. If you do not use an inline oiler/filter system, lubricate the tool daily by holding it so that
the Air Inlet (10B) is facing up.Squeeze theTrigger (13), and place one or two drops of
oil into the Air Inlet (10B). Squeezing the Trigger (13) allows the oil to circulate in the
motor.
5. Repairs to this tool should be performed only by a qualified technician.

Page 8SKU 92421 For technical questions, please call 1-800-444-3353
NOTE: Some parts are listed and shown for illustration purposes only and are not available
individually as replacement parts.
PLEASE READTHE FOLLOWING CAREFULLY
THEMANUFACTURERAND/ORDISTRIBUTOR HAS PROVIDEDTHEPARTSDIAGRAMINTHIS
MANUAL AS A REFERENCE TOOL ONLY. NEITHER THE MANUFACTURER NOR DISTRIBU-
TOR MAKES ANY REPRESENTATION OR WARRANTY OF ANY KIND TO THE BUYER THAT
HE OR SHE IS QUALIFIED TO MAKE ANY REPAIRSTO THE PRODUCT ORTHAT HE OR SHE
IS QUALIFIEDTO REPLACE ANY PARTS OFTHE PRODUCT. IN FACT,THE MANUFACTURER
AND/OR DISTRIBUTOR EXPRESSLY STATES THAT ALL REPAIRS AND PARTS REPLACE-
MENTS SHOULD BE UNDERTAKEN BY CERTIFIED AND LICENSEDTECHNICIANS AND NOT
BY THE BUYER.THE BUYER ASSUMES ALL RISK AND LIABILITY ARISING OUT OF HIS OR
HERREPAIRSTOTHEORIGINAL PRODUCTORREPLACEMENTPARTSTHERETO, OR ARIS-
ING OUT OF HIS OR HER INSTALLATION OF REPLACEMENT PARTS THERETO.
Parts List
Part No. Description Qty. Part No. Description Qty.
1 Trigger Handle 1 28 Cylinder 1
2 Throttle Valve Bushing 1 29 Pin 1
2A Throttle Valve Seat 1 29A Pin 1
3 Throttle Valve Plunger 1 30 Front End Plate 1
4 Throttle Valve 1 31 Front End Bearing 1
5 Throttle Valve Spring 1 32 End Plate Gasket 1
6 0-ring 1 33 Motor Housing 1
10B Air Inlet 1 34 Bearing 1
11 Rubber Cap 1 35 Hammer Pin 2
12 Trigger Pin 2 36 Hammer Frame 1
13 Trigger 1 37 Hammer 2
14 Pin 1 38 Anvil 1
15 F/R Valve Bushing 1 40 Thrust Washer 1
16 0-ring 1 41 Hammer Case Bushing 1
17 Forward/Reverse Valve 1 42 Hammer Case Gasket 1
18 Steel Ball 1 43 Hammer Case 1
19 Spring 1 44 Hammer Case Cp. Scr. 4
20 Pin 1 44A Washer 4
21 Washer 4 45 Handle 1
21A Screw 1 46 Screw 4
22 Handle Gasket 1 46A Washer 4
23 Rear Motor Bearing 1 47 Hammer Case Seal 1
24 Rear End Plate 1 48 Socket Retainer 0-ring 1
26 Rotor Blade 6 49 Socket Retainer 1
27 Rotor 1

Page 9SKU 92421 For technical questions, please call 1-800-444-3353
Assembly Drawing