Harbor Freight Tools Impact Driver 92421 User Manual

1” EARTHQUAKE  
IMPACT WRENCH  
Model 92421  
ASSEMBLY and OPERATING  
INSTRUCTIONS  
®
3491 Mission Oaks Blvd., Camarillo, CA 93011  
TO PREVENT SERIOUS INJURY,  
READ AND UNDERSTAND ALL WARNINGS  
AND INSTRUCTIONS BEFORE USE.  
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.  
For technical questions and replacement parts, 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.  
SKU 92421  
For technical questions, please call 1-800-444-3353  
Page 3  
 
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.  
Air Connection  
Impact  
Wrench  
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
1.  
You will need to prepare a / ” air connector (not included) to connect to the Air Inlet  
2
1
(10B) on the Impact Wrench. First, wrap the / ” air connector with pipe thread seal  
tape before threading it into the Air Inlet (10B). Connect the / ” (or more) ID air source  
2
1
2
hose to a quick connect coupler (not included), and then to the Impact Wrench.  
Note: If you are not using an automatic oiler system, before operation, add a few drops  
of Pneumatic Tool Oil to the airline connection. Add a few drops more after each hour  
of continual use.  
2.  
3.  
Set the air pressure on the regulator to 90 PSI. Do not exceed the recommended air  
pressure of 90 PSI.  
Check the air connection for leaks. Disconnect from the air source.  
SKU 92421  
For technical questions, please call 1-800-444-3353  
Page 4  
 
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.  
FIGURE 1  
Securing with  
Screws (46) and  
Washers (46A)  
(Hex Wrench not included)  
Operation  
Warning!! This Impact Wrench 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 2  
Anvil (38)  
Screw (46) and  
Washer (46A)  
Air Inlet (10B)  
Forward/Reverse Valve (17)  
Side Handle (45)  
FIGURE 3  
Proper way  
to hold the  
Impact Wrench  
SKU 92421  
For technical questions, please call 1-800-444-3353  
Page 5  
 
Operation (continued)  
Refer to FIGURES 2 and 3 on 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.  
2.  
3.  
Select the appropriate size 1” drive socket for your needs.  
Push and snap the socket (not included) onto the Anvil (38).  
To operate the Forward/Reverse Valve (17) follow the directions in FIGURE 4 below.  
FIGURE 4  
Forward  
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.  
Reverse  
Handle  
(Shown without protective coating for clarity.)  
Tightening  
Note: Set the Forward/Reverse Valve (17) so that the anvil turns clockwise (forward).  
7.  
8.  
9.  
Tighten the nut as tight as you can by hand.  
Place the socket (not included) over the nut you wish to tighten.  
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.  
SKU 92421  
For technical questions, please call 1-800-444-3353  
Page 6  
 
Operation (continued)  
Loosening  
Note: Set the Forward/Reverse Valve (17) so that the anvil turns counterclockwise (reverse).  
12.  
13.  
Place the socket (not included) over the nut you wish to loosen.  
Grip the Impact Wrench firmly with two hands and gently squeeze the Trigger (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.  
3.  
Wipe the Impact Wrench down with a lint-free cloth after each use.  
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 the Trigger (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.  
SKU 92421  
For technical questions, please call 1-800-444-3353  
Page 7  
 
Parts List  
Part No.  
1
2
2A  
3
4
Description  
Trigger Handle  
Throttle Valve Bushing 1  
Qty.  
1
Part No.  
Description  
Cylinder  
Pin  
Qty.  
1
1
1
1
1
1
1
1
2
1
2
1
28  
29  
29A  
30  
31  
32  
33  
34  
35  
36  
37  
38  
40  
41  
42  
43  
44  
44A  
45  
46  
46A  
47  
48  
49  
Throttle Valve Seat  
Throttle Valve Plunger  
Throttle Valve  
Throttle Valve Spring  
0-ring  
Air Inlet  
Rubber Cap  
Trigger Pin  
Trigger  
Pin  
F/R Valve Bushing  
0-ring  
Forward/Reverse Valve 1  
Steel Ball  
Spring  
Pin  
Washer  
Screw  
Handle Gasket  
Rear Motor Bearing  
Rear End Plate  
Rotor Blade  
Rotor  
1
1
1
1
1
1
1
2
1
1
1
1
Pin  
Front End Plate  
Front End Bearing  
End Plate Gasket  
Motor Housing  
Bearing  
Hammer Pin  
Hammer Frame  
Hammer  
Anvil  
Thrust Washer  
Hammer Case Bushing 1  
Hammer Case Gasket 1  
Hammer Case  
Hammer Case Cp. Scr. 4  
Washer  
Handle  
Screw  
Washer  
Hammer Case Seal  
Socket Retainer 0-ring 1  
Socket Retainer  
5
6
10B  
11  
12  
13  
14  
15  
16  
17  
18  
19  
20  
21  
21A  
22  
23  
24  
26  
27  
1
1
1
1
4
1
1
1
1
6
1
1
4
1
4
4
1
1
PLEASE READ THE FOLLOWING CAREFULLY  
THE MANUFACTURER AND/OR DISTRIBUTOR HAS PROVIDEDTHE PARTS DIAGRAM INTHIS  
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 REPAIRS TO THE PRODUCT OR THAT HE OR SHE  
IS QUALIFIED TO REPLACE ANY PARTS OF THE PRODUCT. IN FACT, THE MANUFACTURER  
AND/OR DISTRIBUTOR EXPRESSLY STATES THAT ALL REPAIRS AND PARTS REPLACE-  
MENTS SHOULD BE UNDERTAKEN BY CERTIFIED AND LICENSED TECHNICIANS AND NOT  
BY THE BUYER. THE BUYER ASSUMES ALL RISK AND LIABILITY ARISING OUT OF HIS OR  
HER REPAIRSTOTHE ORIGINAL PRODUCT OR REPLACEMENT PARTSTHERETO, OR ARIS-  
ING OUT OF HIS OR HER INSTALLATION OF REPLACEMENT PARTS THERETO.  
NOTE: Some parts are listed and shown for illustration purposes only and are not available  
individually as replacement parts.  
SKU 92421  
For technical questions, please call 1-800-444-3353  
Page 8  
 
Assembly Drawing  
SKU 92421  
For technical questions, please call 1-800-444-3353  
Page 9  
 

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