Northern Industrial 157831 User manual

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1" TWIN HAMMER IMPACT WRENCH KIT
OWNER’S MANUAL
WARNING:
Read carefully and understand all INSTRUCTIONS before
operating. Failure to follow the safety rules and other basic
safety precautions may result in serious personal injury.
It em # 15 78 31

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For technical questions and replacement parts, please call 1-800-222-5381.
Thank you very much for choosing a NORTHERN TOOL + EQUIPMENT CO., Product! For
future reference, please complete the owner’s record below:
Model: _______________ Purchase Date: _______________
Save the receipt, warranty and these instructions. It is important that you read the entire
instruction sheets to become familiar with this product before using it.
This machine is designed for certain applications only. Northern Tool + Equipment strongly
recommend that this machine is not modified and/or used for any application other than that for
which it was designed. If you have any questions relative to a particular application, DO NOT
use the machine until you have first contacted Northern Tool + Equipment to determine if it can
or should be performed on the product.
Before using this product, please read the following instructions carefully.
Technical Specifications
Item
Description
Square Drive
1"
Free Speed
4600 RPM
Max. Torque
1200 ft.-lbs.
Accessories
2-pc. socket set
SAVE THIS MANUAL
You will need this manual for the safety warnings and precautions, assembly, operating,
inspection, maintenance and cleaning procedures, parts list and assembly diagram. Keep this
manual and invoice in a safe and dry place for future reference.
GENERAL SAFETY RULES
Read and understand all instructions.
Failure to follow all instructions listed in the following pages may result in electric shock, fire,
and/or serious injury.
WORK AREA
1. Keep your work area clean and well lit. Cluttered benches and dark areas invite
accidents.
2. Do not operate pneumatic tools in explosive atmospheres, such as in the presence
of flammable liquids, gases, or dust. Pneumatic tools create sparks which may ignite
flammables.
3. Keep bystanders, children, pets and onlookers away while operating a pneumatic
tool. Distractions can cause you to lose control. Protect others in the work area from debris
such as metal filings and sparks. Provide barriers or shields as needed.
PERSONAL SAFETY
1. Stay alert. Watch what you are doing, and use common sense when operating a pneumatic
tool. Do not use a pneumatic tool while tired or under the influence of drugs, alcohol, or
medication. A moment of inattention while operating pneumatic tools may result in serious
personal injury.

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2. Dress properly. Do not wear loose clothing or jewelry. Contain long hair. Keep your hair,
clothing, and gloves away from moving parts. Loose clothes, jewelry, or long hair can be
caught in moving parts.
3. Avoid accidental starting. Be sure the trigger is off before connecting to the air supply.
Carrying pneumatic tools with your finger on the trigger, or connecting pneumatic tools to
the air supply with the Trigger on, invites accidents.
4. Remove adjusting keys or wrenches before turning on the tool. A wrench or a key that is left
attached to a rotating part of the tool may result in personal injury.
5. Do not overreach. Keep proper footing and balance at all times. Proper footing and balance
enables better control of the tool in unexpected situations.
6. Use safety equipment. Always wear ANSI-approved safety glasses underneath a full face
shield, and hearing protection.
PNEUMATIC TOOL USE AND CARE
1. Use clamps or other practical ways to secure and support the workpiece to a stable
platform. Holding the work by hand is unstable and may lead to loss of control. Only work
on a workpiece that is properly secured.
2. Do not force the tool. Use the correct tool for your application. The correct tool will do the
job better and safer at the rate for which it is designed.
3. Do not use the tool if the trigger does not turn it on or off. Any tool that cannot be controlled
with the trigger is dangerous and must be replaced.
4. Disconnect the air hose from the tool before making any adjustments, changing
accessories, or storing the tool. Such preventive safety measures reduce the risk of
starting the tool accidentally.
5. Store idle tools out of reach of children and other untrained persons. Tools are dangerous
in the hands of untrained users.
6. Maintain tools with care. Do not use a damaged tool. Tag damaged tools “Do not use” until
repaired.
7. Check for misalignment or binding of moving parts, breakages of parts, damaged air hose
(not included), and any other condition that may affect the tool’s operation. If damaged,
have the tool serviced before using. Many accidents are caused by poorly maintained
tools.
8. Use only accessories that are recommended by the manufacturer for your model.
Accessories that may be suitable for one tool may become hazardous when used on
another tool.
Service
1. Tool service must be performed only by qualified repair personnel. Service or maintenance
performed by unqualified personnel could result in a risk of injury.
2. When servicing a tool, use only identical replacement parts. Follow instructions in the
Inspection, Maintenance and Cleaning section of this manual. Use of unauthorized parts
or failure to follow maintenance instructions may create a risk of injury.
Additional Safety Warnings
1. Use clean, dry, regulated, compressed air at 90 PSI. Do not exceed the recommended 90
PSI. Never use oxygen, carbon dioxide, combustible gases, or any other bottled gas as a
power source for this tool.

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2. When connecting to the air supply: Prior to each use, if an automatic oiler is not used, add
two drops of air tool oil (not included) into the air inlet fitting of the tool.
3. Always disconnect the tool from its compressed air supply source, and squeeze the trigger
to release all compressed air in the tool before performing any maintenance or service.
4. The warnings, precautions, and instructions discussed in this manual can not cover all
possible conditions and situations that may occur. The operator must understand that
common sense and caution are factors which cannot be built into this product, but must be
supplied by the operator.
Operation
To attach a quick connector
WARNING Prior to performing any assembly and/or adjustment procedures,
make sure the air supply hose (not included) is disconnected from the impact wrench.
1. Prior to use, the impact wrench requires the attachment of a quick-connector into its air inlet.
To do so, wrap approximately 3" of pipe thread sealer tape (not included) around the male
threads of a quick-connector. Then, firmly tighten the quick-connector into the air inlet.
Fig. 1
Loosening
1. Attach the correct size socket to the anvil.
2. Set the compressor’s pressure regulator to 90 PSI. Do not set the compressor’s outlet
regulator above 90PSI.
3. Connect the tool to the air compressor’s hose. If leakage is detected, disconnect the air
hose and fix it correct before use.
4. Place the socket over the nut to loosen.
5. Grip the tool firmly. Press the REVERSE valve in from the area above the trigger so that the
REVERSE valve protrudes out the back of the housing. Press the trigger to start the tool.
(Caution: Make sure the nut or bolt can withstand the impact wrench’s working torque.)
NOTE:
If the tool cannot loosen the nut, DO NOT raise the outlet pressure of the air compressor.
When the nut is moved, stop the tool by releasing the trigger and remove the tool from the
nut. Remove the nut from the socket if needed.
Tightening
The max. torque of the impact wrench is 1,200 ft.-lbs. Make sure that the nut or bolt you
are using the tool to tighten can withstand the rated torque.
1. Tighten the nut as far as you can by hand.
2. Place the socket on the nut. Press the REVERSE valve forward so it protrudes out the front

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of the housing. Press the trigger to start the tool.
NOTE:
If the tool stalls while tightening, DO NOT raise the outlet pressure of the air compressor
above 90 PSI.
When the nut has been tightened, remove the tool and socket. Do not over-tighten.
If available, check the recommended torque specifications for the nut. You should use a
torque wrench to torque the nut after using the impact wrench.
MAINTENANCE
Always make sure the trigger is in its “OFF” position, and disconnect the tool from its
compressed air supply before performing any inspection, adjustments, maintenance, or
cleaning.
1. Before each use, inspect the general condition of the tool. Check for loose screws,
misalignment or binding of moving parts, cracked or broken parts, damaged air hose, and
any other condition that may affect its safe operation. If abnormal noise or vibration occurs,
have the problem corrected before further use. Do not use damaged equipment.
2. Daily: With a clean cloth, remove all dirt, oil, and grease from the tool. If necessary, you
may use a mild detergent. Do not use solvents, as damaged to the tool may occur. Do not
immerse the tool in any liquids.
GENERAL TOUBLESHOOTING
•TROUBLE
Tool does not run at a normal speed or at a variable speed
The motor locks up
Automatically starts when connected to compressed air.
Torque decreases
Abnormal vibrations – Excessive heat rising from housing
•CAUSES
Air pressure is not enough
Speed controller/switch breaks down
Rotor blades break or wear out
Dust gets into the motor
Throttle lever or starting trigger malfunctions
Air leakage at the inlet or somewhere else
Bearing damage
Correspondent O-rings wear out or out of position
Lack of lubrication
•TROUBLESHOOTING
Check the air hose to see whether it is blocked or twisted
Check the air compressor to gain the correct air pressure required
Replace rotor blades
Check and fix the throttle lever or starting trigger for accurate operation
Check the air leakage and repair under proper instruction
Replace new bearing
Replace the damaged O-ring or put it back in correct position
Oil/Lubricate the tool consistently until it gains the right speed and torque
•NOTE: For any other special troubles which cannot be rectified by the operator,

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please contact qualified repair personnel.
Diagram
Parts List
MANUFACTURER’S LIMITED WARRANTY
The limited warranty set forth below is given by Northern Tool + Equipment Company Inc., (NTE)

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with respect to new merchandise purchased and used in the United States, its possessions and
territories.
NTE warrants this product against defects in material and workmanship for a period of 12 months
parts/ 12 months labor commencing on the date of original purchase and will, at its option, repair
or replace, free of charge, any part found to be defective in material or workmanship. This limited
warranty shall only apply if this product has been operated and maintained in accordance with the
Owner’s Manual furnished with the product, and has not been subject to misuse, abuse,
commercial use, neglect, accident, improper maintenance, alteration, vandalism, theft, fire, water
or damage because of other peril or natural disaster. Damage resulting from the installation or use
of any accessory or attachment not approved by NTE for use with the products(s) covered by this
manual will void your warranty as to any resulting damage. This warranty is limited to ninety (90)
days from the date of original retail purchase for any NTE product that is used for rental or
commercial purposes, or any other income-producing purposes.
This limited warranty does not provide coverage in the following cases:
1. Failure to heed the Pneumatic Tool Use and Car as outlined on pages 3 and 4 of
this manual.
2. Failure to follow specific Set Up instructions as outlined on page 5 of this
manual.
NTE reserves the right to change or improve the design of any NTE product without assuming any
obligation to modify any product previously manufactured.
No implied warranty, including any implied warranty of merchantability or fitness for a
particular purpose, applies after the applicable period of express written warranty above as
to the parts as identified. No other express warranty or guaranty, whether written or oral,
except as mentioned above, given by any person or entity, including a dealer or retailer,
with respect to any product shall bind NTE during the period of the Warranty, the exclusive
remedy is repair or replacement of the product as set forth above. (Some states do not allow
limitations on how long an implied warranty lasts, so the above limitation may not apply to you.)
The provisions as set forth in this warranty provide the sole and exclusive remedy arising
from the sales. NTE shall not be liable for incidental or consequential loss or damages
including, without limitation, expenses incurred for substitute or related expenses, or for
rental expenses to temporarily replace a warranted product. (Some states do not allow
limitations on how long an implied warranty lasts, so the above limitation may not apply to you.)
In no event shall recovery of any kind be greater than the amount of the purchase price of the
product sold. Alteration of the safety features of the product shall void this warranty. You assume
the risk and liability for loss, damage, or injury to you and your property and/or to others and their
property arising out of the use or misuse or inability to use the product.
This limited warranty shall not extend to anyone other than the original purchaser, original lessee
or the person for whom it was purchased as a gift.
How State Law Relates to this Warranty: This warranty gives you specific legal rights, and you
may also have other rights which vary from state to state.

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For questions about your warranty, please call 1-800-222-5381.
WARNING
Some dust created by power sanding, sawing, grinding, drilling, and other construction activities
contains chemicals known to the State of California to cause cancer, birth defects or other
reproductive harm. Some examples of these chemicals are:
• Lead from lead-based paints
• Crystalline silica from bricks and cement and other masonry products
• Arsenic and chromium from chemically treated lumber.
Your risk from these exposures varies, depending on how often you do this type of work. To reduce
your exposure to these chemicals: work in a well-ventilated area, and work with approved safety
equipment, such as those dust masks that are specially designed to filter out microscopic particles.
Northern Tool + Equipment Co., Inc.
2800 Southcross Drive West
P.O. Box 1499 Burnsville, MN 5337-0499
Made in China