Universal Tool UT8750 Specifications

Important
Read these instructions carefully before installing, operating,
servicing or repairing this tool. Keep these instructions in a safe
accessible place.
Includes-ForeseenUse,WorkStations,PuttingIntoService,Operating,
Dismantling, Assembly and Safety Rules
Operator Instructions
Manufacturer/Supplier Product Type RPM
Cycles Per Min
Model No/Nos Serial No
Product Nett Weight
lbs
Kg
Recommended Use Of
Balancer Or Support
Recommended Hose Bore
Size - Minimum
Recommended Max.
Hose Length
Ins M/M Ft M
No
Air Pressure
Recommended Working 6.3 bar 90 PSI
Recommended Minimum n/a bar n/a PSI
Maximum 7.0 bar 100 PSI
Personal Safety Equipment
Use - Safety Glasses Yes
Use - Safety Gloves Yes
Use - Safety Boots
Use - Breathing Masks Yes
Use - Ear Protectors Yes
Page No 1
Angle Disc Grinder
10mm Dia Threaded Shaft
UT8750 - 4” Disc (100mm)
UT8750A - 4½” Disc (115mm)
UT8750B - 5” Disc (125mm)
3.87
1.76 3/8 10 30 10
12,000
Universal Air Tool Company Limited
Unit 8
Lane End Industrial Park
High Wycombe
Bucks
HP14 3BY
Work Stations
The tool should only be used as a hand held hand operated tool. It is
alwaysrecommendedthatthetoolis used whenstandingon a solid
floor. It can be used in other positions but before any such use the
operator must be in a secure position having a firm grip and footing
andbeawareofthesafetyrulestobeobeyedwhenusingthesander.
Foreseen Use of Tool
This right angle grinder is designed to be used with reinforced resin
bonded depressed centre grinding wheels that have a permitted
rotationalspeedinexcessof12,000RPM.Seepartslistsfordetailsof
available wheel sizes.
The tool is designed to be used for light grinding and dressing of
welds, etc. but not for cutting off. The grinder must never be used if
a wheel guard (disc cover) item (3) is not fitted.
Tel No Fax No(01494) 883300 (01494) 883237
Noise Level Sound Pressure Level 82.9 dB(A)
Test Method Tested in accordance with Pneurop
test code PN8NTC1 and ISO Standard 3744
Vibration Level
Test Method Tested in accordance with ISO
standards 8662/1 & 8662/4
5.1 Metres / Sec²
Putting Into Service
Air Supply
Use a clean lubricated air supply
that will give a measured air
pressureatthetoolof90p.s.i./6.3
bar when the tool is running with
the trigger/lever fully depressed.
Use recommended hose size and
length.Itis recommended that the
tool is connected to the air supply
as shown in figure 1. Do not
connect the tool to the air line
systemwithoutincorporatinganeasytoreachandoperateairshutoff
valve.Theairsupplyshouldbelubricated.Itisstronglyrecommended
thatan air filter, regulator, lubricator (FRL) isused as shown in Figure
1asthiswillsupplyclean,lubricatedairatthe correctpressuretothe
tool.Detailsofsuchequipmentcanbeobtainedfromyoursupplier.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
pressingthetrigger on the tool. Disconnect the air line and pour into
theintakebushingateaspoonful(5ml)ofasuitablepneumaticmotor
lubricatingoilpreferablyincorporatingarustinhibitor.Reconnecttool
to air supply and run tool slowly for a few seconds to allow air to
circulatetheoil.Iftoolis usedfrequentlylubricateondailybasisandif
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
pressureswiththemaximumpermittedworkingairpressureof100
p.s.i./7 bar.

Page No 2
Safety Rules For A Grinder
1)Readalltheinstructionsbeforeusingthistool.Alloperatorsmustbe
fully trained in its use and aware of these safety rules.
2) Do not exceed the maximum working air pressure.
3) Use personal safety equipment.
4) Use only compressed air at the recommended conditions.
5) If the tool appears to malfunction remove from use immediately
and arrange for service and repair.
6) If the tool is used with a balancer or other support device ensure
that it is fixed securely.
7)Alwayskeephandsawayfromtheworkingattachmentfittedtothe
tool.
8)Thetoolisnotelectricallyinsulated.Neverusethetoolifthereisany
chance of it coming into contact with live electricity.
9) Always when using the tool adopt a firm footing and/or position
andgripthetoolfirmlytobeabletocounteract anyforces orreaction
forces that may be generated whilst using the tool.
10) Use only correct spare parts. Do not improvise or make
temporary repairs.
11) Do not lock, tape, wire, etc. the on/off valve in the run position.
Thetrigger/leveretc.mustalwaysbefreetoreturntothe‘off’position
when it is released.
12) Always shut off the air supply to the tool, and depress the
trigger/lever etc. to exhaust air from the feed hose before fitting,
adjusting or removing the working attachment.
13)Check hose and fittingsregularlyforwear. Replace if necessary.
Do not carry the tool by its hose and ensure the hand is remote from
theon/offcontrolwhencarryingthetoolwiththeairsupplyconnected.
14) Take care against entanglement of moving parts of the tool with
Operating
With the grinder correctly connected to the air supply, check the
speed of the grinder with an inlet pressure of 100 psi/7.0 bar
measuredatthetoolinlet.Checkwithacalibratedtachometer.Check
thattheguardisinpositionandsecurelyfixed.Checkthatthegrinding
wheel is of correct dimensions, is not cracked or chipped and has a
permittedspeedratinghigherthanthemaximumpermissiblerunning
speed of the grinder which is 12,000 RPM. Check that item 5 disc
receiver is the correct type as parts list and is screwed tightly to the
shaft and locates the bore of the grinding wheel on the spigot of the
disc receiver and screw on disc nut item (4) using the spanners
provided.Donotovertightenasthiscouldcrackthe wheel.Itshould
betight enough to prevent wheel spin off when the air supply is shut
off.
Whenfirststartingthegrinderwithaneworchangedwheelfitted,the
grinder should first be started in a protected area, i.e. such as under
a heavy bench well away from other persons and run for, say, one
minute.Thiswillprovideprotectionifthewheelshouldbreakbecause
some fault was not detected.
Always use eye protection and wear protective gloves if there are
sharp edges in the working area. The tool and the grinding process
can create a noise level such that ear protectors should be worn.
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.Ifthisissothenspecialbreathingapparatusmayberequired.
Seek advice before starting work.
Ifthegrindervibrateswhenfirstfittingthewheelorduringuse,remove
from service immediately and arrange for the fault to be corrected
before continuing to use.
Do not apply excessive pressure as this will reduce the cutting
efficiency. Apply light loads and allow the wheel to cut.
Handle the grinder with care. If the grinder is dropped, carefully
examine the wheel for damage and replace if necessary. Start the
machine as if for the first time of fitting a wheel, i.e. under a bench.
Make sure the object to be ground is in a firm fixed position.
Dismantling & Assembly Instructions
Disconnect tool from air supply.
Gripgearshaft(11)withspanner(41)andinsertspanner(40)intothe
holes in disc nut (4), unscrew disc nut (4) and take off grinding disc
(34)anddisc receiver (5), remove 4 off screws (37) and take off disc
cover(3),retainer(7)andgasket(8).Pulloutthedriveshaftassembly
from body (1). Unscrew grip (6) from body (1) and remove 2 off
screws (16) and take off exhaust cover (48). Remove spacer (14).
Support bearing (14) and tap the non threaded end of the gear shaft
(11) to drive it through the bearing (14). Take off retaining ring (13)
from gear shaft (11) and support bearing (9) on the threaded shaft
side and press the non threaded end of gear shaft (11) through the
assemblytoseparategearshaft(11),key(12),bearing(9),bevelgear
(10) and wave washer (43).
By holding body (1) in a vice fitted with soft jaws the control head
assembly may be removed from body (1) by unscrewing lock ring
(50). It is then possible to pull out the motor and governor assembly
fromthebody (1).Pulloffpinionassemblyfrommotorassemblyand
press apart pinion (15) and bearing (18). Grip the front plate (20) by
hand and with a non metallic or soft metal (lead or aluminium)
hammer tap the splined end of rotor (24) to drive the rotor and the
remainder of the motor and governor assembly through the front
plate and bearing assembly. Take off the cylinder (23) noting its
orientation for reassembly and take out 4 off rotor blades (25) from
rotor (24). Spring pin (22) may be pulled out of cylinder (23) if a
replacement is required.
Grip rotor (24) in a vice with soft jaws and unscrew the governor
assemblyfromtherotor-lefthandthread.Supporttherearendplate
(26) in a piece of tube with a bore as close as possible to the
maximum diameter of the rotor and very carefully so as not to
damagethethread,taptherotorthrough the rear end plate (26) and
bearing assembly. With a suitable punch tap out bearing (17) from
rear end plate (26) and bearing (17) from front plate (20).
Todismantlethegovernorassemblyfirstunscrewadjustscrew(42)
assembly. Take off spring (28). Drive out 2 off spring pins (47) and
take out 8 off pendulums (45) from governor (44). When removing
the pendulums take special note of the orientation to the governor
(45) to ensure they are fitted the same way on reassembly. This is
important.
Grip valve housing (56) in a vice and remove O-ring (39) from lock
ring (50). Drive out pin (58) and take off safety throttle lever (60). Do
notdismantlethethrottlelever(60).Unscrewbushing(57).Unscrew
valvenut(52)andremovewithO-ring(53),spring(54),valve(59)and
O-ring (55).
Unscrewcouplingnut(51)-lefthandthread-fromvalvehousing(56)
andunscrew lock ring (50)fromcouplingnut (51).and unscrew lock
ring (50) from coupling nut (51).
Reassembly
Clean all parts and examine for wear. Use only distributor or
manufacturer supplied spare parts. Particularly examine O-rings,
bearings and gears. Coat all parts in a pneumatic tool lubricating oil,
onepreferablycontainingarustinhibitor.Greasebearingsandgears
with a molybdenum or lithium based general purpose grease.
Reassemble in the reverse order. See Note below.
Forthemotormakesurethattheendplatesthatabutthecylinderare
free from burrs and sharp edges and if necessary lap on a flat fine
grade of abrasive paper. Press bearing (17) into rear case (26) and
supporttheinner race of bearing (17) and press the non splined end
ofrotor (24) into the assembly. Tap the rotor relativeto the rear case
and bearing assembly until a clearance of approx. 0.0025”
(0.065mm)is achieved betweentherotor and therearcase. Ensure
therotorspinsfreelybeforeassemblingtherestofthemotorassembly.
This machine has a speed controller or governor, parts (21), (28),
(42), (44), (45) and (46). The correct setting of this speed controller
is critical to the safety of the tool and should only be carried out by a
trainedcompetentperson.Thespeedissetbyassemblingthespeed
controller,measuringtheoutputspindlegearshaft(11)speedwitha
calibratedtachometer.Adjustmenttothespindlespeedcanbemade
by rotating adjust screw (42). The speed of the grinder running free
withanair inlet pressure of 100 psi(7bar)measuredat inlet bushing
(57) must not exceed 12,000 RPM.

UT8750
UT8750A
UT8750B
4” Disc (100mm) Angle Disc Grinder
4½” Disc (115mm) Angle Disc Grinder
5” Disc (125mm) Angle Disc Grinder
Page No 3
Mar 98 Ver 1.11
Ref No Part No Description
1250001A Body
2250002 Screw
3250003 Disc Cover (4" Disc) HA39 Disc Cover (4½" Disc)
HA40 Disc Cover (5" Disc)
4250004 Disc Nut (4" Disc) 250004-22 Disc Nut (4½" Disc)
250004-22 Disc Nut (5" Disc)
5250004 Disc Receiver (4" Disc) 250005-22 Disc Receiver (4½" Disc)
250005-22 Disc Receiver (5" Disc)
6250006 Grip
7250007 Retainer
8250008 Gasket
9250009 Ball Bearing
10 250010 Bevel Gear
11 250011 Gear Shaft
12 250012 Key
13 250013 Reataining Ring
14 250014 Ball Bearing
15 250015 Pinion Gear
16 250016 Screw (2)
17 250017 Ball Bearing (2)
18 250018 Ball Bearing
19 250020 Spacer
20 250021 Front Plate
21 832H01 Governer Assembly
22 250024 Sprint Pin
Ref No Part No Description
23 250025 Cylinder
24 250026 Rotor
25 250027 Rotor Blade (4)
26 250028 Rear Plate
28 250030 Spring
34 H0060 Disc Wheel
36 250061A Valve Bushing
37 250039 Cap Screw (4)
39 250041 O-Ring
40 250042 Disc Spanner
41 250043 Stop Spanner
42 250044 Adjust Screw
43 250045 Wave Washer
44 250046 Governor
45 250047 Pendulum (8)
46 250048 Plunger
47 250049 Spring Pin (2)
48 250050 Exhaust Cover
50 250052 Lock Ring
51 250053 Coupling Ring
52 250054 Valve Screw
53 250055 O-Ring
54 250056 Valve Spring
55 250057 O-Ring
56 250058 Valve Housing
57 250059 Hose Adaptor
58 250060 Spring Pin
59 250061 Valve Pin
60 250062 Complete Lever
Assembly

Accessories
clothing, ties, hair, cleaning rags, etc. This will cause the body to be
drawn towards the tool and can be very dangerous.
15) It is expected that users will adopt safe working practices and
observe all relevant legal requirements when installing, using or
maintaining the tool.
16) Do not install the tool unless an easily accessible and easily
operable on/off valve is incorporated in the air supply.
17) Take care that the tool exhaust air does not cause a problem or
blows on another person.
18) Never lay a tool down unless the working attachment has
stopped moving.
19) A grinding wheel should only be fitted by a competent person
trained to do so. The wheel must be of the correct size and speed
rating.
20) Check the speed of the grinder at least once per week, if it is in
regular use, with an accurate tachometer.
21)The tool must onlybeused with the grindingwheelsas set outin
section“ForeseenUse of the Tool” and shown on parts list. Never fit
any other device.
22) Carry out the instructions as set out in “Putting into Service”.
23) Many countries have local or national rules re the use and fitting
of grinding wheels. Make sure such rules are observed.
24)Usea barrier to preventsparkscausingahazard to the operator,
any other person or anything within the vicinity of the sparks.
25) If a wheel guard becomes damaged or has withstood a wheel
breakage, the guard must be changed.
26) Do not use chipped or cracked grinding wheels.
27) Always wear impact resistant eye protection.
28) Use only the disc plates, Items (4) and (5) provided with the
grinder for locating and clamping the wheel. Never use substitutes.
Usethepaperblotterfixedtothewheelasthisensureseventightness
when the wheel is secured.
29) Tighten the wheel plates sufficiently to prevent wheel spin off
whenthegrinderisturnedoff.Donottightenexcessivelyasthismay
crack the wheel.
30) The noise from the tool or the process noise of the grinding
operation may be such that hearing protection should be worn.
31) Avoid inhaling dust from the grinding process. Wearing of a
breathing mask is recommended. Grinder certain materials may
meanthatspecialbreathingprecautionsarenecessary.Seekadvice
before using the tool.
32) Always ensure that the workpiece is firmly supported so that it
cannot move during the grinding process.
33) If the grinder is dropped do not use unless the wheel is first
checked for damage by a competent person.
34) When not in use the grinder should be stored in a safe place
whereit will not be damaged. If a tool has notbeen used for a period
of time check the tool as for the first time of using.
35) Be aware that if the grinding process causes high vibration,
special precautions should be taken.
Distributor
Notes
Page No 4
Declaration of Conformity
Universal Air Tool Company Limited
Unit 8, Lane End Industrial Park, High Wycombe, Bucks, HP14 3BY, England
declare under our sole responsibility that the product
Models UT8750, UT8750A, UT8750B Angle Disc Grinder, Serial Number
to which this declaration relates is in conformity with the following standard(s) or other normative document(s)
EN792 (Draft), EN292 Parts 1 & 2, ISO 8662 Parts 1 & 4, Pneurop PN8NTC1
following the provisions of 89/392/EEC as amended by 91/368/EEC & 93/44/EEC Directives
Place and date of issue Name and signature or equivalent marking of authorised person
Lane End D.H.Moppett (Man. Director)
This document may not be copied wholly or in part by anyone without the consent of the Directors of Universal Air Tool Company Limited
© Copyright of Universal Air Tool Company Limited, established in the United Kingdom, 1994
36) The operator should be aware that the grinding wheel will
continuetorotateafterthepowersupplyhasbeenshutoff.Thiscould
cause a hazard.
37) Always store grinding wheels in accordance with the
manufacturer’s instructions.
38) Check frequently that the spindle thread has not become
damaged or worn.
39) Always ensure that the grinding wheel has a higher permissible
running speed to the speed of the grinder.
Designed & Written in the U.K.