Dismantling & assembly instructions, Safety rules when using a drill, Reassembly – Universal Air Tools UT8824 User Manual
Page 2: Motor assembly

Operating
Select suitable drill bit, insert the shank into the drill chuck as far
as possible and tighten chuck with key supplied making sure
that the shank of the device is securely clamped centrally
between the three chuck jaws. Remove chuck key.
When drilling holes of all sizes it is advised to use a pointed
punch to mark the centre at which the hole is to be drilled as
this will provide a starting point for the drill tip. This procedure
will prevent the drill bit from skidding, ensure that the hole is
drilled where intended and help to prevent drill breakage when
using small drills. When drilling, particularly with small diameter
drills, always try to ensure that load applied to the drill is such
that the drill bit is always at right angles to the hole being drilled.
Do not force the drill but allow it to cut.
When drilling always adopt a firm posture to be able to
counteract any sudden movement of the drill due to torque
reaction. Such torque reaction can occur when the drill stalls
due to a too heavy load being applied or the material being too
hard or tough. The torque reaction can occur when the drill
breaks through the material being drilled, particularly on sheet
metal. Always use eye protection and hand protection is
advised, particularly when drilling holes in metals where the
material being removed from the hole is in the form of long
sharp strips. Do not tie the drill chuck key to the drill as the
attaching device i.e. string or chain could become entangled
with the rotating chuck and bit etc.
If using an abrasive device, drilling stone or performing any
operation where dust is created, it is recommended to use a
breathing mask.
Always ensure that the material to be drilled is firmly fixed to
prevent its movement.
It is also recommended that when drilling holes of large
diameter to first pre drill a hole of smaller diameter as this will
reduce effort required to drill the hole and minimise torque
reaction.
Dismantling & Assembly Instructions
Disconnect drill from air supply.
The drill chuck (25) may be removed by placing the chuck
adjusting key securely in the chuck and giving the key a sharp
tap with a hammer in the direction to loosen a right hand
threaded joint. If this fails to remove the chuck remove it after
the gearbox assembly has been removed from the drill handle.
(See later). Place motor housing (1) in a vice fitted with soft jaws
with the handle section pointing upwards, unscrew bushing
(26), remove screw (4) and exhaust deflector (3). Unscrew
locknut (24) to remove gearbox and pull out motor assembly.
If the drill chuck has not been removed as it is too tightly fitted,
it can be removed as follows. Pull off ring gear (20) from
gearbox and pull off 3 off idler gears (21). Use a suitable square
section bar inserted between the pins in idler gear plate (22),
pushed up against the face to ensure that contact is made at the
bottom of the pins and unscrew the chuck using the chuck key.
Do not use a round bar or locate at the outer edge of the pins
as this may distort the 3 pins. A length of 8mm (0.312) square
bar is ideal for this purpose. Continue to dismantle the gearbox
by supporting ball bearings (23) on the gear side in a piece of
tube of suitable bore to just clear the largest diameter of idler
gear plate (22) and press out idler gear plate from bearings 2
off- (23). It is recommended that the pins in the idler plate (22)
are not removed for replacement and the complete idler gear
plate (22) is replaced. For information the nominal diameter of
the three pins in the idler plate (22) is 0.1574 ins (4 mm).
Replacement is required if the pins are badly damaged or worn
below 0.155 (3.937 mm) diameter.
To dismantle motor assembly grip the front end plate (19) tightly
by hand and tap the gear end of the rotor with a non metallic or
soft metal (lead or aluminium) hammer through the front end
plate (19) and bearing (13). Remove 4 off rotor blades (17) and
cylinder (18). Hook out plastic shield from rear end plate (14).
Support rear end plate (14) in a piece of tube with a bore size
as close as possible to the largest diameter of the rotor (14) and
tap the non splined end of the rotor to remove it from the rear
end plate and bearing assembly. Tap out bearing (13) from rear
end plate (14) and bearing (13) from front end plate (19).
Tap out trigger retaining pin (2) and pull out trigger assembly.
Remove trigger (10) from valve stem (6). Remove valve stem (6)
from valve bushing (9) and remove O-Rings (5). Remove 2 off
O-Rings (7) and O-ring (8) from valve bushing (9).
Reassembly
Clean all component parts and examine for wear before
reassembling. Use only manufacturers or distributor supplied
spare parts. Check in particular for wear and cuts on O-Rings
and wear on rotor blades. Lightly coat all parts with a suitable
pneumatic tool lubricating oil. Pack all bearings and gearbox
with a general purpose lithium or molybdenum based general
purpose grease.
Assemble in reverse order - see notes below.
Motor Assembly
If fitting a new rotor very lightly deburr the edges of the rotor
slots. Make sure rotor blade slots are clean. Make sure that the
faces of the front and rear end plates (19) and (14) that abut
cylinder (18) are free from burrs and surface marking. If
necessary lap faces on a flat, very fine grade of abrasive paper.
Press bearing (13) into end plates (14) and (19). Support bearing
(13) in rear end plate on the inner race and tap rotor on the gear
end with a soft metal or non metallic hammer until the rotor
locates against the face of the rear end plate. Support the inner
face of the rear end plate in a piece of tube with a bore diameter
as close as possible to the largest diameter of the rotor and tap
the non splined end until a clearance of 0.040mm (0.0015") to
0.065mm (0.0025") is obtained between the inner face of the
rear end plate and the rotor. This clearance to be checked when
pulling the rotor by hand away from the rear end plate and
bearing assembly.
Spin rotor to ensure that it will spin freely in the rear end plate
and bearing assembly. Fit rotor blades and cylinder ensuring that
the pin in one end of the rotor cylinder locates in the round hole
in the rear end plate. Push on front end plate and check that
rotor still rotates freely.
Reassemble tool in reverse order.
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 preferably incorporating a rust
inhibitor. Reconnect tool to air supply and run tool slowly for a
few seconds 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.
Page No 2
Safety Rules When Using A Drill
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) Always select a suitable cutting, abrasive device suitable for
use with this drill.
3) Always shut off the air supply to the drill and depress the
trigger to exhaust air from the feed hose before fitting, adjusting
or removing the device. Remove drill chuck.
4) Always adopt a firm footing and/or position and be aware of
torque reaction developed by the drill.
5) Use only correct spare parts.