Universal Air Tools UT8738 - Manual (Page 2)

Operating
Select a suitable mounted point that has a free running speed higher
than the maximum running speed marked on the tool. Make sure that
the diameter of the shank exactly matches the diameter of the collet
mounted in the grinder. There are five standard sizes of collet available
for use with this grinder, i.e.
1) - 1/4" Dia (0.250ins) (6.35mm)
2) - 6mm (0.236ins)
3) - 1/8" (0.125ins) (3.175mm)
4) - 3mm (0.118ins)
5) - 8mm (0.315ins)
Never try to force a 1/4" diameter shank into a 6mm collet or a 1/8"
diameter shank into a 3mm collet. Never try to close a 1/4" diameter
collet to secure a 6mm shank or a 1/8" diameter collet to secure a
3mm diameter shank. Always match correctly the shank size to the
collet size. If uncertain, have parts measured by a competent person.
Push the shank as far as possible
into the collet and tighten the
collet nut using the spanners
provided on the collet nut and
output spindle.
The shank of the mounted point
may be pulled forward from the
maximum insertion length but
always ensure a minimum
gripping length of not less than
10mm - See Figure 2.
Be aware that the allowed
running speed of the mounted
point is lowered because of an
increase in the length of the shank
between the end of the collet and
the body of the mounted point. This distance is shown in Diagram 2 as
"LO" and is called the overhang. The information with respect to
mounted point size, permissible running speed and reduction in
running speed due to an increase in overhang is available from the
supplier of the mounted point.
If the increase in overhang for access reasons takes the permissible
running speed of the mounted point below the free running speed of
the grinder select a smaller diameter mounted point.
The fitting of the mounted point should be done by a trained operator.
When first starting the grinder with a new wheel fitted, the grinder
should not be near other persons and be held in a protected area, i.e.
under a bench and run for a few seconds. This will protect personnel
from possible effects of damage to the mounted point before it was
fitted to the grinder i.e. wheel breakage.
Always use eye protection and wear protective gloves if there are sharp
edges in the work area. The tool and the grinding process can create a
noise level such that the use of ear protectors is advised.
If the grinding process creates a dust then use a suitable breathing
mask.
Check that the material being worked will not cause harmful dust or
fumes. If this is so then special breathing masks may be required.
If the grinder vibrates when first fitting a mounted point or during
operation, remove from service immediately and correct fault before
continuing to use.
Do not apply excessive pressure as this will reduce the cutting efficiency
and can bend the shank of the mounted point causing vibration and the
possibility of breakage. Apply light loads to allow the wheel to cut.
Handle the grinder with care. If the grinder is dropped, carefully check
the mounted point for damage, i.e. cracks, chipping and start for the
first time as for fitting a new wheel i.e. under a bench.
Dismantling & Assembly Instructions
Disconnect tool from air supply.
Grip housing (1) with comfort grip (35) in a vise fitted with soft jaws. With
a snap ring plier, remove the snap ring (38). By using an adjustable
wrench, unscrew the air hose assembly (39), swivel air inlet (36) and air
inlet (13) then separate o-ring (3), connecting ring (37), muffler (14) and
o-ring (3). With a wide bladed screw driver unscrew valve plug (10) and
remove o-ring (9), (8), air regulator (7), spring (6), throttle pin (5), o-rings
(4). Do not remove throttle valve bushing (2) with o-rings (3) unless a
replacement is required.
Use a proper steel bar, tap out pin (12) and remove throttle lever (11)
from housing (1).
Release housing (1) with comfort grip (35) from vise, slide off comfort
grip (35) from housing (1) then return housing (1) to vise.
With an adjustable wrench, unscrew spindle housing (27) from housing
(1). Pull out (28) to (33) from spindle housing (27). Unscrew collet nut
(33) and pull out collet (32). Unscrew chuck spindle (31), take out
retaining ring (28) and remove ball bearings (29) from extension spindle
(30). Remove spindle (25) and housing cap (26).
Pull out the motor assembly from housing (1). Grip the front end plate
(23), to avoid the splines of rotor (18) from
damage, use a rubber hammer, slightly tap the
splinted end of the rotor (18) through the front
end plate (23) and ball bearing (24) assembly.
Take off cylinder (21) and remove spacer (20)
and rotor blades (19). With a suitable punch,
tap the rear end of rotor (18) slightly to
separate rotor (18) from rear end plate (16).
Then press out ball bearing (24) from front end plate (23) and ball
bearing (15) from rear end plate (16). Do not remove steel balls (22)
and pin (17) from front end plate (23) and rear end plate (16) unless
replacements are required.
Reassemble
Clean all parts and examine for wear, replacing any worn or
damaged parts. Use only replacement parts obtained from
the manufacturer or an authorized distributor. Lightly coat all
parts with a suitable pneumatic tool lubricating oil and
assemble tool in reverse order.
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
Never exceed the maximum air pressure. If there is this possibility
always use this grinder with a pressure reducing valve fitted in the
supply line. Your supplier will advise of suitable equipment.
D = diameter of mounted point
T = length of mounted point
Lo = overhang
S = diameter of shank
Lg = gripping length
Figure 2. Gripping length of collet and chuck
Safety Rules When Using A Die Grinder
1) Read all the instructions before using this tool. All operators must be
fully trained in its use and aware of these safety rules.
2) Always select suitable abrasive to use with this tool - see Operating
Instructions.
3) Always shut off the air supply to the grinder and depress the lever to
exhaust air from the feed hose before fitting, adjusting or removing the
mounted point.
4) Always adopt a firm footing and/or position before using the grinder.
5) Use only correct spare parts.
6) Check hose and fittings regularly for wear. Do not carry the tool by its
hose.
7) Do not remove and never tie down the safety lever.
8) Never exceed the maximum air pressure and check the free running
speed frequently. Have air regulator fully open when making speed
checks.
9) Use safety equipment as recommended.