CHESTER Cobra Mill User manual

CobraMill
InstructionManual
ChesterUKLtd
ClwydClose,HawardenIndustrialPk
Hawarden,NrChester
Flintshire.CH53PZ
Tel:01244531631
Email:[e-mail]
www.chesteruk.net

Contents
1. Introduction 2
2. Health&Safety 35
3. MachineSpecification 67
4. Operation 89
5. Controls 10
6. PartDiagrams&Lists 1113
7.CircuitDiagram 1415
8. GuideToMilling 16
ChesterUKCobraMill
1

Introduction
ChesterUKLimitedisaspecialistcompanythathasbeensupplyingthemachinetoolindustryfor
over15years.TheChesterUKHeadOfficecomprisesofa30,500sq.ftfactorycompletewithofficesand
a showroom. Specialisingin conventional machine tools, Chester has built a reputation for quality and
reliability,whichishighlyregardedinthemachinetoolindustryandthemodelengineeringmarket.
Thereareseveral divisionswithinthecompany;Export,Education, ModelEngineering &UKSales,all
withdedicatedsalespersonnelwhoaretrainedtoansweryourquestions.
When buying from Chester you can be assured of a complete backup service with mechanical and
electricalengineersthatareavailabletogiveadviceifrequired.
StockisalargepartofanybusinessandChesterhavealwaysinvestedsubstantiallyinbuildingalarge
quantity of machines and spares, ready to satisfy customer requirements. Chester UK has one of the
largest stocks ofconventionalnew machines andaccessories within Great Britain. Pleasetake time to
visitourwebsite: www.chesteruk.net
ChesterUKCobraMill
2

Health&Safety
Aswithallmachinerytherearecertainhazardsinvolvedwiththeoperationanduseofthelathe.
Using the machine with respect and caution will considerably lessen the possibility of person injury.
However, if normal safety precautions are overlooked or ignored, personal injury to the operator may
result.
Thismachinewasdesignedforcertainapplicationsonly.Westronglyrecommendthatthemachineisnot
modified,and/orusedforanyapplicationotherthanwhichitwasdesigned.Ifyouhaveanyquestions
relativetoitsapplicationdonotusethemachine,untilyouhavefirstbeenincontactwithChester
UK.
The lathe may not arrive with a power socket or plug. In the event of this happening, please inform
ChesterUKonTel:(01244)531631.
Safetyrulesforalltools
User
1. Wearcorrectapparel
Nolooseclothing,gloves,rings,braceletsor otherjewellerytoget caughtinmovingparts.Non
slipfootwearisrecommended.Wearprotectivehaircoveringtocontainlonghair.
2. Alwaysweareyeprotection
Refer to ANSLZ87.1 standard for appropriate recommendations. Also use face and / or a dust
maskifthecuttingoperationisdusty.
3. Don’toverreach
Keepaproperfootingandbalanceatalltimes.
4. Neverstandonatool
Seriousinjurycouldoccurifthetoolistippedorifthecuttingtoolisaccidentallycontacted.
5. Neverleavethetoolrunningunattended
Turnpoweroff.Leavetooluntilitcomestoacompletestop.
6. Drugs,alcoholandmedication
Donotoperatethetoolwhileundertheinfluenceofdrugs,alcoholoranymedication.
7. Makesurethetoolisdisconnectedfromthepowersupply
Whilemotorisbeingmounted,connectedorreconnected.
8. Always
Keephandsandfingersawayfromanymovingparts.
9. Stop
Themachinebeforemovingchips.
10.Shutoff
Powerandcleanthelatheandworkareabeforeleavingthemachine.
Useofthemachine
1. Removeadjustingkeysandwrenches
Form a habit of checking to see that keys and adjusting wrenches are removed from the tool
beforeturningit‘on’.
2. Don’tforcethetool
Itwilldothejobbetterandbesaferattherateforwhichitwasdesigned.
3. Usetherighttool
Don’tforcethetoolorattachmenttodoajobforwhichitwasnotdesigned.
4. Securework
Useclampsoravicetoholdworkwhenpractical.It’ssaferthanusingyourhands,andfreesboth
tooperatethemachine.
ChesterUKCobraMill
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5. Maintaintoolsintopcondition
Keeptoolssharpandcleanforthebestandsafestperformance.Followinstructionsforlubricating
andchangingaccessories.
6. Userecommendedaccessories
ConsultChesterUKforrecommendedaccessories.Theuseofimproperaccessoriesmaycause
hazards.
7. Avoidaccidentalstarting
Makesuretheswitchisinthe‘OFF’positionbeforeplugginginpowercord.
8. Stop
Themachinebeforeputtingmaterialinthevice.
9. Always
Havestockfirmlyclampedinthevicebeforestartingthecut.
10. Groundalltools
If the tool is equipped with a threeprong plug, it should be plugged into a threehole electrical
receptacle.Ifanadapterisusedtoaccommodateatwoprongreceptacle,theadapterplugmust
beattachedtoaknownground.Neverremovethethirdprong.
Adjustment
Make all adjustments with the power off.When assembling follow the manuals instructions, this
willensurecorrectinstructionandasafestructure.
Workingenvironment
1. Keeptheworkareaclean
Clutteredareasandbenchesinviteaccidents.
2. Don’tuseinadangerousenvironment
Don’tusepowertoolsindamporwetlocations,orexposetorain.Keeptheworkareawelllit.
3. Keepchildrenetcatasafedistance.
Allchildrenetcshouldbekeptatasafedistancefromtheworkarea.
4. Don’t
Install&usethismachineinanexplosivedangerousenvironment.
Maintenance
1. Disconnect
Machinefromthepowersourcewhenmakingrepairs.
2. Checkdamagedparts
Beforefurtheruseofthetool,aguardorotherpartthatisdamagedshouldbecarefullycheckedto
ensure that it would operate properly and perform its intended function check for alignment of
movingparts,bindingofmovingparts,breakageofparts,mountingandanyotherconditionsthat
may affect its operation. A guard or other part that is damaged should be properly repaired or
replaced.
3. Disconnecttools
Beforeservicingandwhenchangingaccessoriessuchasbladesbits,cutters,etc.
4. Toprevent
Thecorrosionofmachinedsurfaceswhenasolubleisusedascoolant,payparticularattentionto
wipingdrythesurfaceswherefluidaccumulatesanddoesnotevaporatequickly,suchasbetween
themachinebedandvice.
ChesterUKCobraMill
4

SafetyDevice
1. Interlockswitchonpulleycover.Assoonasthepulleycoverisopen,themachinewillcometo
a stop with the function of this switch. Do not remove this switch from the machine for any
reason,andcheckit’sfunctionfrequently.
2. Interlockswitchoncuttingarea.Assoonasthepulleycoverisopen,themachinewillcometo
a stop with the function of this switch. Do not remove this switch from the machine for any
reason,andcheckit’sfunctionfrequently.
ChesterUKCobraMill
5

MachineSpecification
DrillingCapacity 10mm
EndMillingCapacity 10mm
FaceMillingCapacity 20mm
SpindleStroke 30mm
Throat 140mm
TableWorkingSurface 145x240mm
LongitudinalTravel 180mm
CrossTravel 90mm
Max.DistanceSpindleToTable 220mm
No.OfSpindleSpeeds Variable
RangeOfSpeeds 1002000rpm
SpindleTaper MT2
Motor 150W
Supply 240V
Weight(nw/gw) 25/38kg
Dimensions(LxWxH) 480x380x680mm
ChesterUKCobraMill
6

Features
1.Forward/Off/ReverseSwitch 2.VariableSpeedControlKnob 3.FuseBox
4.PowerLight(Green) 5.YellowLight(only110V) 6.HighLowChangeKnob
7. 8.FineFeedingHandwheel 9.
10.WorkTable 11.CrossFeedHandwheel 12.LongitudinalFeedHandwheel
13.Handle 14.LiftingHandwheel 15.DCMotor
ChesterUKCobraMill
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Operation
InstallationOfTheTaperedShank
1. Disconnectfromthemainpowersupply,beforeyoureplacethecutter.
2. Removetheprotectivecover(a).
3. Wipethespindlesleeveandtapershank.
4. Putthetapershank(i)intothespindlesleeve.Mattthecutterwithanoilcloth.
5. Usea#14openendwrench(c),turningthespindledrawbar(clockwise)(b),inordertosecure
thetaperedshank.
6. Pulloutthefixingpin
7. Installtheprotectivecover(a).
RemovalOfTheTaperedShank
1. Disconnectfromthemainpowersupply,beforeyoureplacethecutter.
2. Removetheprotectivecover(a).
3. Usea#14openendwrench(c),toloosenthespindledrawbar(counterclockwise)(i),inorder
toremovethetaperedshank.
4. Knockthetapershank(i)(gentlywithaplastichammer)toloosenitinthespindlesleeve.
5. Mattthecutterwithanoilcloth.
6. Installtheprotectivecover(a).
ChesterUKCobraMill
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TravelAdjustment
Theliftinghandlecanbeusedtocontrolthetravellingofthespindlebox.
1. Loosenthescrewinsidethespindlebox.
2. Rotationoftheliftinghandlewillmovethespindleboxupordown.
FineFeeding
Tooperatethefinefeed,pushtheclutchleverin.Thiswillenablethehandwheelforthefinefeed.
MitreWedgeAdjustment
Inthelongtermwearwilloccuronthedovetail.Thiswillcauseinaccuracythatcanbeeliminatedby
adjustingthemitrewedge(adjustingthedovetailgibstrip).Adjustingthescrewslidesthetaperedstripto
reducethegapandrestoreaccuracyofthemill.
Thefollowingadjustmentsarepossible:
1. Base&YAxisCrossSlide.
2. XAxisCrossSlide&WorkTable
3. MillHeadSeat&VerticalColumn.
4. MillHead&Spindle.
TheWayToAdjust
1. Loosenthelockednuts.
2. Adjust the foremost pressure of the mitre wedge by locked nut. If necessary, loosen all the
adjustingscrewstothesame.
3. Tightenand loosen the adjusting screws, also keeping the pressure of each adjusting screw
thesame.
4. Tightenthelockednutuniformly.
5. Whenthenutislocked,pleaseusethe#3interiorhexagonalwrenchtofixtheadjustingscrew
fromrotating(thiswillcauseanunbalanceinthepressure).
6. Please adjust the middle portion first and then go to toward the interior from two sides
uniformlywhileyouareadjustingthescrewinordertoensureuniformpressure.
ChesterUKCobraMill
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Controls
InitialStart
Set the HIGH / LOW range lever to low. Connect to the power supply. Select FORWARD, using the
FORWARD/OFF/REVERSESwitch(A)onthemaincontrolPanel,thenthepowerlamp(B)lights.
SwitchontheCobraMillbyslowlyturningtheVariableSpeedControlKnob(C)clockwise.
Thespeedwillincreaseprogressivelythefurthertheknobisturned.
Runforatotalof5minutes;graduallyincreasethespindlespeedtoitsmaximum.Runattopspeedforat
least2minutesattopspeedbeforestopping.
Checkthatallcomponentsaresecure,workingfreelyandcorrectly.
CheckthattheCobraMillismountedsecurely.
RepeattheprocedureataHIGHspeedsetting.
Caution
NeverattempttochangefromaHIGHtoaLOWspeedwhilstthemachineisrunning.
StartingUnderNormalConditions
1. Takeallthenecessaryprecautionspreviouslystated,andensuretheworkpieceisfixedfirmly.
2. Selectanappropriatespeedlevel.
3. SelecttheFORWARD/off/REVERSEtoaFORWARDorREVERSEposition.
4. Proceedtostartthemachineasdescribedabove.
5. Whilstnotinuse,switchoffanddisconnectfromthepowersupply.
Notice
When using 100~120v power, the socket will have to have a auto overload protective function. If the
feedistofast,orthedrillingistoodeep,theCobraMillwillstopworkingandayellowlight(behindthe
fuselage)willlightup.ByturningtheVariableSpeedcontrolknob(D)andthenturnonagain,theCobra
willnowworkagainandtheyellowlampwilloffautomatically.
ChesterUKCobraMill
10

PartDiagrams&Lists
ChesterUKCobraMill
11

No. Description Q'ty No. Description Q'ty
1 ScrewM4x12 2 38 Shiftshaft 1
2 Coverforthemotor 1 39 Key4x8 1
3 ScrewM6x12 3 40 Key4x12 1
4 Springwasher6 3 41 Changegear 1
5 Washer6 3 42 Dialfork 1
6 DCmotor 1 43 Flangelining 2
7 Roundkey 1 44 Checkring21 1
8 Checkringforshaft8 2 45 Spacer 1
46 Variablespeedcontrolknob 1
10 Motorgear 1 47 Springpin2x12 1
11 Safetycover 1 48 Wedge 1
12 ScrewM4x6 1 49 ScrewM5x18 4
13 ScrewM4x8 4 50 NutM5 4
14 Washer4 4 51 Handle 1
15 Upcover 1 52 PinA3x12 1
16 Sleevesupportplate 1 53 Jointshaft 1
17 ScrewM6x5 1 54 ScrewM5x18 1
18 Compressionspring 1 55 Jointscrew 1
19 Steelball5 1 56 Wormbase 1
20 Gearbox 1 57 Helicalgear 1
21 Spindlesleeve 1 58 Spacer 1
22 ScrewM6x14 2 59 PinA3x18 1
23 Bearing619052E 2 60 Key2x18 1
24 Spindlebox 1 61 Wormshaft 1
25 Checkringforhole38 2 62 Dial 1
26 Springseatring 1 63 Dampspring 1
27 Compressionspring 1 64 Handwheel 1
28 Roundnutstopgasket 1
29 RoundnutM24x1.5 1
30 Spindlegear 1 67 Washer6 4
31 Spacer 1 68 TopnutM6 4
32 Spindlegear 1 69 ScrewM6x20 1
33 Checkringforshaft20 1
34 Powdermetallurgybearing 2 71 ScrewM4x20 2
35 Gear 1 72 ScrewM4X18 8
36 Checkringforshaft10 1 73 NutM4 8
37 Changegear 1 74A Base 1
ChesterUKCobraMill
12

No. Description Q'ty No. Description Q'ty
75 ScrewM6x20 2 119 Diallabel 1
77 Lockscrew 1 120 Electricitybox 1
78 Spindle 1 121 PCBoard 1
79 Key4x28 1 122 Powerindicatorlight 1
84 ScrewM8x50 1 123 Fusebox 1
85 Fixscrew 1 124 Metachoresisswitch 1
86 Gearshaft 1 125 Forward/reverseswitch 1
87 Handleshaft 1 126 Electricitylabel 1
88 Longhandlesleeve 1 127 ScrewST2.9x6.5 4
89 Springpin3x12 2 128 Powerline 1
90 Markshowsleeve 1 129 Cautionlabel 1
91 ScrewM5x8 2 130 Spindleaxislabel 1
92 ScrewM6x20 4 *131 Technicalparameterlabel 1
93 Pin6x26 2 *132 Drillchuck 1
94 Nutblock 1 *133 InsideSixhomWrenchS:3,6 1
95 Liftingscrew 1 *134 DoubleendWrench:5.5*,8*10 1
96 Screwsupport 1 *135 RoundnutWrenchD=3842 1
97 Handwheel 3 *136 Oilcan 1
98 Handlebolt 3 *137 Fuse 1
99 Handlesleeve 3 *138 Tapershank 1
100 Key3x10 3 *139 Chuckkey 1
101 Coverboard 1 *140 Tnut 4
102A Fuselage 1 141 Crossscrew 1
103 Screw 4 142 Crosswedge 1
105 Worktable 1 143 Connectplatesupport 1
107 Dampspring 2 144 Connectflange 1
108 Dial 2 145 Roundclampplate 1
109 ScrewM6x16 4 146 Scale 1
110 Screwbase 2 147 Finger 1
111 Lengthwaysscrew 2 148 ScrewM6*6 1
112 ScrewM4x8 4 149 ScrewM8*25 4
113 Screwnut 2 150 ScrewM6*25 2
114A Saddle 1 151 Labelrivet2*3 2
115 Wedge 2 152 Pin6*35 2
116 Changespeedlabel 1
117 Jointlabel 1
118 0positionlabel 2
ChesterUKCobraMill
13

CircuitDiagram
220~240V/5060Hz
ChesterUKCobraMill
14

100~120V/5060Hz
ChesterUKCobraMill
15

GuideToMilling
Contents
1. Introduction
2. TypesofMillingMachine
2.1HorizontalMillingMachine
2.2VerticalMillingMachine
3. CuttingTools
3.1CuttingToolsforHorizontal
MillingMachine
3.2CuttingToolsforVertical
MillingMachine
4. IndustrialApplications
5. MillingProcesses
5.1SpindleSpeed
5.2FeedRate
5.3DepthofCut
5.4DirectionofCutterRotation
6. TypicalMillingOperations
6.1PlainMilling
6.2EndMilling
6.3GangMilling
6.4StraddleMilling
7. MillingSetUp
7.1ViceAlignment
7.2WorkHoldingMethod
8. Safety
1.Introduction
Millingmachineisoneofthemostversatileconventionalmachinetoolswithawiderangeofmetal
cuttingcapability.Manycomplicatedoperationssuchasindexing,gangmilling,andstraddlemillingetc.
canbecarriedoutonamillingmachine.
Thistrainingmoduleisintendedtogiveyouagoodappreciationonthetypeofmillingmachinesand
thevarioustypesofmillingprocesses.Emphasisisplacedonitsindustrialapplications,operations,and
theselectionofappropriatecuttingtools.
Oncompletionofthismodule,youwill
acquiresomeofthesetechniquesfromthe
trainingexercisesasillustratedinfigure1.
However,togainmaximumbenefit,you
arestronglyadvisedtomakeyourself
familiarwiththefollowingnotesbefore
undertakingthetrainingactivities,andto
haveagoodinteractionbetweenyourself
andthestaffinchargeofyourtraining.
Assessmentofyourtrainingwillbebased
onacombinationofyourskillandattitude
ingettingtheworkdone.
Figure1.MillingProducts

2.TypesofMillingMachine
Mostofthemillingmachineareconstructedof¡¥columnandknee¡¦structureandtheyareclassified
intotwomaintypesnamelyHorizontalMillingMachineandVerticalMillingMachine.Thename
HorizontalorVerticalisgiventothemachinebyvirtueofitsspindleaxis.Horizontalmachinescanbe
furtherclassifiedintoPlainHorizontalandUniversalMillingMachine.Themaindifferencebetweenthe
twoisthatthetableofanUniversalMillingMachinecanbesetatanangleforhelicalmillingwhilethe
tableofaPlainHorizontalMillingMachineisnot.
2.1.HorizontalMillingMachine
Figure2showsthemainfeaturesofaPlainHorizontalMillingMachine.
Theirfunctionsare:
a.Column
Thecolumnhousesthespindle,thebearings,
thegearbox,theclutches,theshafts,the
pumps,andtheshiftingmechanismsfor
transmittingpowerfromtheelectricmotortothe
spindleataselectedspeed.
b.Knee
Thekneemountedinfrontofthecolumnisfor
supportingthetableandtoprovideanupor
downmotionalongtheZaxis.
c.Saddle
Thesaddleconsistsoftwoslideways,oneonthe
topandoneatthebottomlocatedat90ºtoeach
other,forprovidingmotionsintheXorYaxesby
meansofleadscrews.
d.Table
Thetableismountedontopofthesaddleand
canbemovedalongtheXaxis.Ontopofthe
tablearesomeTslotsforthemountingof
workpieceorclampingfixtures.
e.Arbor
Thearborisanextensionofthespindlefor
mountingcutters.Usually,thethreadendofan
arborisoflefthandhelix.
Figure2.HorizontalMillingMachine

2.2.VerticalMi
llingMachine

Figure6.SlittingSaw
Note:Horizontalmillingcuttersarespecifiedbythename,thematerial,thewidth,thediameter,andthe
hubsizeofthecutter.
Example Sideandfacecutter,
HighSpeedSteel,
Cuttersize:10Xø100
Hubsize:ø25
3.2.CuttingtoolsforVerticalMilling
a.EndMills
Commonlyusedforfacing,slottingandprofilemilling.
Figure7.EndMill
b.RoughCutEndMills
Forrapidmetalremoval.
Figure8.RoughCutEndMill
c.SlotDrills
Forproducingpocketswithoutdrillingaholebeforehand.
Figure9.SlotDrill
d.FaceMillingCutters
Forheavycutting.
Figure10.FaceMillingCutter
Note:Mostverticalmillingcuttersareofendmilltypesandarespecifiedbythematerial,thediameter,
thelength,thehelicalangle,thetypesofshankandtheshankdiameter.Forfacemillingcutter,onlythe
diameterofthecutterandthetypesofcarbideinsertsarerequired.