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10 ► IW12 User Manual
WRENCH TORQUE INFORMATION
FACTORS THAT AFFECT TORQUE
An impact wrench is a rotary hammer that impacts the
head of a bolt or nut. It does not apply a slow steady
torque as a standard torque wrench. Therefore, sever-
al factors affect the result of torque when using impact
wrenches:
1. LONG BOLTS. Long bolts having high-friction
threads with lubrication under the bolt head or as-
sociated nut can twist when impacted, then untwist
before the next impact. This will especially happen if
there is low friction between the bolt head or nut and
the mating surface.
2. HEAVY, LOOSE OR MULTIPLE ADAPTERS.
Heavy, loose or multiple adapters between the
wrench and socket can dissipate the intensity of the
impact to the bolt head or nut.
3. AMOUNT OF IMPACT. Maximum torque results can
be obtained by allowing continuous impacting of the
socket against the bolt head or nut for at least 10
seconds.
4. HYDRAULIC FLOW RATE. If the ow rate to the
tool is too low, the hammer (or impact) speed is re-
duced. If the ow is correct, a change in the relief
pressure does not affect the impact force. Poorly
designed hydraulic circuits can result in lower ow
rates and reduced impact speeds when pressure is
required during impacting.
BOLT GRADE AND THREAD
RECOMMENDATIONS
Allowable bolt torque is limited by both bolt thread di-
ameter and grade of steel in the bolt. The IW12 Impact
Wrench is recommended for use on the following bolt
grade and thread sizes:
SAE Grade 2 1 to 1-1/2 inch / 25/38 mm
SAE Grade 5 3/4 to 1-1/4 inch / 19-32 mm
SAE Grade 8 5/8 to 1 inch / 16-25 mm
PREOPERATION PROCEDURES
CHECK POWER SOURCE
1. Using a calibrated ow meter and pressure gauge,
check that the hydraulic power source develops a
ow of 4–12 gpm/15-45 lpm at 1000–2000 psi/70-
140 bar.
2. Make certain that the hydraulic power source is
equipped with a relief valve set to open at 2100
psi/145 bar minimum.
CONNECT HOSES
1. Wipe all hose couplers with a clean, lint-free cloth
before making connections.
2. Connect hoses from the hydraulic power source to
the tool ttings or quick disconnects. It is good prac-
tice to connect the return hose rst and disconnect it
last to minimize or eliminate trapped pressure within
the wrench.
3.
WARNING
Always use sockets and accessories designed for
impact type applications. DO NOT USE STANDARD
SOCKETS OR ACCESSORIES. THESE CAN
CRACK OR FRACTURE DURING OPERATION.
Observe the ow indicators stamped on the main
body assembly and the hose couplers to ensure that
the ow is in the proper directions. The female cou-
ple on the tools “IN” port is the inlet (pressure) cou-
pler.
NOTE:
If the uncoupled hoses are left in the sun, pressure
increase within the hoses can make them difcult to
connect. Whenever possible, connect the free ends
of hoses together.
WRENCH OPERATION
The IW12 is designed for 3/4-inch square sockets and
accessories. Adapter part number 06790 or equivalent
will permit the use of 5/8-inch quick change drive attach-
ments.
Normal applications include installation or removal of
fasteners requiring torque in the range of 300–1200 ft
lb/407–1627 Nm and auger bit wood boring. DO NOT
use the wrench as a hammer drill for metal drilling.
During normal operation it is common to see some
grease leakage from around the anvil during hard use.
Refer to the IW12 Service Manual for the correct lubrica-
tion procedures.
1. Observe all Safety Precautions.
2. Move the hydraulic circuit control valve to the “ON”
position to operate the wrench.
OPERATION