Operator Instructions
Includes - Foreseen Us e, Work Stations, Putting Into Serv ice,
Operating, Dismantling, Assembly and Safety Rules
Important
Read these instructions carefully before installing,
operating, servicing or repairing this tool. Keep these
instructions in a safe accessible place.
Manufacturer/Supplier Product Type
Universal Air Tool Company Limited
Unit 8
Lane End Industrial Park
High Wycombe
Bucks
3/8 Sq. Drive Butterfly
Lever Impact Wrench
Model No/Nos Serial No
UT8020-T
HP14 3BY
Tel No Fax No
(01494) 883300 (01494) 883237
RPM
10,000
Cycles Per Min
Product Nett Weight
1.9
0.88
Recommended Working
Recommended Mini mum
Maximum
lbs
Kg
Recommended Use Of
Balancer Or Support
Air Pressure
6.3
bar
n/a
bar
7
bar
No
90
n/a
100
Perso n a l Sa fe t y E q ui pm en t
Use - Safety Glasses
Yes
Use - Safety Gloves
Use - Safety Boots
Use - Breathing Masks
Use - Ear Protectors
Yes
Foreseen Use Of Tool
The impact wrench is designed for the tightening and loosening
of threade d fas ten er s w ithin the ra nge as spe cifie d by the
manufacturer. It should only be used in conjunction with suitable
impact type 3/8" square female drive nut running sockets. Only
use sockets which are of the impact type.
It is allowed to use suitable extension bars, universal joints and
socket adaptors between the square output drive of the impact
wrench and the square female drive of the socket.
Do not use the tool for any other purpose than that specified
with out co nsul ti ng th e ma nufa ctur er or th e man uf act urer 's
authorised supplier. To do so may be dangerous.
Never u se an impact wre nch as a ha mmer to dislodge or
straighte n cross threaded fas teners. Never a ttempt to modify
the tool for other uses and never modify the tool for even its
recommended use as a nutrunner.
Work Stations
The tool should only be used as a handheld
hand operated tool. It is always recom-
mended that the tool is used when standing
on the solid floor. It can be used in other
positions but before any such use, the opera-
tor must be in a secure position having a firm
grip and footing and be aware that when
loosening fasteners the tool can move quite
quickly away from the fastener being undone.
An allowance must always be made for this
rearward movement so as to avoid the possi-
bility of hand/arm/body entrapment.
Recommended Hose Bore
Size - Minimum
3/8 10 30 10
Ins M/M Ft M
Noise Level
PSI
Test Method
PSI
test code PN8NTC1 and ISO Standard 3744
PSI
Vibration Level
Test Method
Sound Pressure Level 90.3 dB(A)
Sound Power Level 100.3 dB(A)
Tested in accordance with Pneurop
2.8
Tested in accordance with ISO
standard 8662 Parts 1 & 7
Putting Into Service
Air Supply
Use a clean lubricated air supply that will give a measured air
pressure at the tool of 90 p.s.i./6.3 bar when the tool is running
with the trigger fully depresse d and the air regu lator in its
maximum opening flow position. Use recommended hose size
and length. It is recommended that the tool is connected to the
air supply as shown in figure 1. Do not connect a quick connect
coupling directly to the tool but use a whip or leader hose of say
approximately 12 inches length. Do not connect the tool to the
air line sys tem withou t incorporating an easy to reach a nd
operate air shut off valve. The air supply should be lubricated. It
is strongly recommended that an air filter, regulator, lubricator
(FRL) is used as shown in Figure 1 as this will supply clean ,
lubricated air at the correct pressure to the tool. Details of such
equipment can be obtained from your supplier. If such
equipment is not used then the tool should be lubricated by
shutting off the air supply to the tool, depressurising the line by
Recommended Max.
Hose Length
Metres / Sec²
Page No 1
pressing the trigger on the tool. Disconnect the air line and pour
into the intake bushing a teaspoonful (5ml) of a suitable
pneumatic motor lubricating oil prefe rably incorporating a rust
inhibitor. Reconnect tool to air supply and run tool slowly for a
few sec onds to allow air to circulate the oil. If tool is used
frequently lubricate on daily basis and if tool starts to slow or
lose power.
It is recommended that the air pressure at the tool whilst the
tool is running is 90 p.s.i./6.3 bar. The tool can run at lower and
higher pressures with the maximum permitted working air
pressure of 100 p.s.i./7.0 bar. For a lower air pressure the tool
will give a lower output for a given setting of the air regulator set
for 90 p si o perat io n and an i ncrea sed o utp ut fo r hig her
pressures. Hence it is possible that changes in supply pressure
can gi ve si tuat io ns wher e the fast ener i s und er o r o ver
tightened. For changes in pressure, the regulator position and
application should be reassessed.
Operating
The output of the impact wrench in prime working condition is
governed by mainly three factors
a) the input air pressure
b) the time the impact wrench is operated on the joint. Normal
time for joints of average tension requirement 3 to 5 seconds
c) the setting of the air regulator for a given joint a t a given
pressure operated for a given time.
The air regulator item (15) can be used to regulate the output of
the impact wrench if no other control means is available. It is
strongly recommended that an external pressure regulator
ideally as part of a filter/regulator/lubricator (FRL) is used to
control air inlet pressure so that the pressure can be set to help
control the ten sion requ ired to be applied to the th readed
fastener joint.
There is no consistent reliable torque adjustment on an impact
wrench of this type. However, the air regulator can be used to
adjust torque to the approximate tightness of a known threaded
joint. To set the tool to the desired torque, select a nut or screw
of known tightness of th e same size, th read pitch and thre ad
condition as those on the job. Turn air regulator to low position,
apply wrench to nut and gradually increase power (turn regulator
to admit more air) until nut moves slightly in the direction it was
originally se t. The tool is now s et to duplicate tha t tightness,
note regulator setting for future use. When tightening nuts not
requiring critical torque values, run nut up flush and then tighten
an additional one-quarter to one-half turn (slight additional
turning is necessary if gaskets are being clamped) . For
additional power needed on disassembly work, turn regulator to
its fully open position. This impact wrench is rated a 3/8" bolt
size. Rating must be down graded for spring U bolts, tie bolts,
long cap sc rews, double depth nuts, badly ruste d conditions
and spring fasteners as they absorb much of the impact power.
When possible, clamp or wedge the bolt to prevent spring back.
Soak rusted nuts in penetrating oil and break rust seal before
removing with impact wrench. If nut does not start to move in
three to five seconds use a larger size impact wrench. Do not
use impact wrench beyond rated capacity as this will drastically
reduce tool life.
Note: Actual torque on a fastener is directly related to joint
hardness, tool speed, condition of socket and the time the tool
is allowed to impact.
Dismantling & Assembly Instructions
Disconnect tool from air supply.
Remove plug (7) and O-ring (8) and invert tool and drain oil from
front end into a suitable receptacle. Grip tool in vice locating on
the square drive of anvil (44). Unscrew 2 off screws (19) and
retainer plate (17). Pull out air regulator (15) complete with O-
ring (12). O-rings (11) and (12) may be removed from stem of
inlet bushing (10). Unscrew 2 off cap screws (49) and 2 off cap
screws (50) and remove together with 4 off lock washers (46)
to release housing cap (9) and gasket (27) from the assembly.
At this stage remove throttle lever (5) together with 2 off throttle
lever pins. Unless replacements are required do not extract 2 off
lever pins from throttle lever (5).
From housing cap assembly pull off 2 off plungers (26), remove
2 off plunger springs (25) and 2 off valve pins (24). It is then
possible to lev er out 2 off valves (23) and 2 off springs (22)
taking care not to allow the spring to fly away.
Pull out motor pin (34) and extract the assembly comprising of
retaining ring (20), rear end plate (29), bearing (28), rotor (30),
6 off rotor blades (32) and cylinder (33). Note at this time the
way cylinder (33) is removed and note that it must be
reassembled in the same way with the chamfer on the outside
diameter to end face at the front end of the tool. Remove rotor
blades from rotor, take off re taining ring (20) an d pull rotor
through rear end plate and bearing assembly. Using a suitable
punch bearing (28) may be removed from rear plate (29).
Pull out front end plate (35) complete with O-ring (36) and
carefully prise off the O-ring. Remove bearing (37) and seal (36)
from plate (35). Remove retaining ring (39) from motor housing
(1) and the complete hammer mechanism comprising of anvil
(44) complete with socket retainer (46) and O-ring (45), hammer
cage (40), hammer dog (42), cam (41) and hammer pin (43)
may be extracted from the motor housing (1). Socket retainer
(46) and O-ring (45) may be prised off of anvil (44).
Oil seal (3) may be hooked out of the front of motor housing and
anvil bushing (2) pressed out.
Reassembly
Examine all parts for wear and examine O-rings and seals for
sign s o f c ut s o r we ar e t c. Par t i cu l ar l y e xam i n e a nv i l ( 44 )
particularly around the square drive area, hammer dog (42) and
cam (41) for wear and cracks. Replace any part with those
supplied by the manufacturer or an authorised distributor.
Clean and lubricate all parts with a suitable pneumatic tool
lubricating oil and reassemble in the reverse order. On
completion of as sembly check anvil will rotate and le ver and
reverse valves operate freely. Remove plug (7) and O-ring (8)
and inject approx. 1/2 ounce (15cc) of a SAE10 or 20 oil.
Replace plug and O-r i ng. In ject appr o x. 5 m l of a su i t ab le
pneuma tic tool lubricating oil (prefera bly incorporating a ru st
inhibitor) into the tool via air inlet bushing (10). Connect tool to
a suitable air supply, run tool slowly for a few seconds to allow
oil to circulate and reset for operation. See section "Operating".
Safety Rules When Using an Impact
Wrench
1) Read all the instructions before using this tool. All operators
must be fully trained in its use and aware of these safety rules.
All service and repair must be carried out by trained personnel.
2) The socket used must be of the correct drive size and the
"impact" type. Never use sockets other than impact type.
3) Do not use sockets with excessive wear to the input and
output drives. Check that the square on any other type of drive
or the impact wrench is not cracked or excessively worn before
fitting or changing socket, extension, etc. Make sure that the
socket is firmly fixed to the tool.
4) Always ensure that a sta ble position or footing is adopted
before using the tool.
5) Ensure that the tool has been correctly set up on a test joint.
Incorrect set up could cause joint breakage with sudden and
unexpected movement of the tool.
6) Use only correct spare parts for repair.
7) Always ensure that the reverse valve is in the correct position
before operating the tool. Do not run the tool unless the socket
is first located on the joint.
8) Check hose and fittings regularly for wear. Use quick connect
Page No 2