6第6章
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Followingmarkingtraining,weproceededtohacksawingpractice,themostphysicallydemandingandstamina-consumingprocedureinbenchwork.Ahandhacksawconsistsofaframeandablade.Wheninstallingtheblade,cuttingteethmustfaceforwardwithmoderatetightness;overlytightbladestendtosnap,whilelooseonesbendeasilyandresultindeviatedcuttingpaths.Hacksawingimposesstrictrequirementsonposture,forceandrhythm:standfirmlywithfeetapartandleanslightlyforward,gripthehacksawframetightlywithbothhandsandkeeparmsstraighttopushandpullsteadily.Applycuttingforceonlyonforwardstrokesandliftthebladegentlywithoutpressureonreturnstrokes,maintainingasteadypacethroughouttoavoidabruptspeedchangesorexcessiveforce.
WhenIfirststartedhacksawing,Ihadnumerousproblems:stiffpostures,unevenpushingforceandchaoticrhythmledtofrequentbladejamming,pathdeviation,unevencuttingsurfacesandevenbentsawblades.Meanwhile,repetitivemovementscausedseveresorenessandstiffnessinarmsandwrists,easilytriggeringimpetuousandslackemotions.Undertheinstructor’sguidance,Iadjustedmystandingpostureandforceapplicationmethod,sloweddownthepaceandprioritizedstabilityoverspeedtokeepcuttingpathsstraight.Throughconstantdrills,Igraduallybecameproficientinhacksawingtechniques,capableofstablesawingwithgreatlyimprovedflatnessofcuttingsurfacesanddimensionalprecision.Thispracticealsotemperedmypatienceandstressresistance,makingmerealizethetruththatfineworkmanshipcomeswithslowandcarefuleffortsinbenchwork.
Filingstoodasthecoreandkeyprocedureofthisinternship,aswellasthedecisivestepaffectingsurfacequalityanddimensionalaccuracyofworkpieces,takingupmostofthetraininghours.Filesareclassifiedintoroughfiles,mediumfilesandsmoothfiles:roughfilesquicklyremoveexcessblankallowance,mediumfilestrimoutlinestonominaldimensions,andsmoothfilesperformprecisionfinishingtoimprovesurfacefinish.Filingdemandsseamlesscoordinationofbothhands,balancedforceandsteadymovements.Thefilemustmovehorizontallyandparallellywithoutup-and-downswinging,otherwiseunevensurfacesanddimensionaldeviationswilloccur.
Duringpracticaloperation,Istrictlyfollowedtheprincipleof"roughfilingfirst,precisionfinishinglaterandstep-by-stepprocessing".Ifirstusedroughfilestostripsurplusmaterialsrapidly,switchedtomediumfilestotrimcontoursonceapproachingstandarddimensions,andfinallyadoptedsmoothfilesforfinishingpolishingtoguaranteeflatplanes,regularedgesandprecisesizes.Filingisanextremelyconcentration-intensivetask;slightcarelessnessinforceoranglecontrolwillleadtooversizedimensionsorinclinedplanes.Duringtraining,impetuosityandunstablehandmovementsoncecausedwornedgesandunevensurfaces.Ononeoccasion,excessivefilingresultedinundersizedworkpiecesthatrequiredrework.Throughrepeatedmistakesandrevisions,Ideeplyrealizedthatnocarelessnessisallowedinbenchwork,asmillimeter-leveldeviationswillimpairtheserviceperformanceofmechanicalparts.Icalmeddownandsloweddownoperations,measuringdimensionswithcalipersandtrysquaresaftereveryfewfilingstrokestoadjustposturestimely.Eventually,Imasteredflatfiling,curvedsurfacetrimmingandchamferpolishingproficiently,andthefinishedworkpiecesmettrainingstandar