Vernier bevel protractor

Vernier bevel protractor

• 1.
  BEVEL PROTRACTORS /Universal bevel protractor: Bevelprotractorsarenothingbutangularmeasuringinstruments. Typesofbevelprotractors : Thedifferenttypesofbevelprotractorsusedare: 1)Vernier bevel protractor 2)Universal protractor 3 ) O p t i c a l p r o t r a c t o r O p t i c a l p r o t r a c t o r : Working principle: -Avernierbevelprotractorisattachedwithacuteangleattachment. – Thebodyisdesigneditsbackisflatandnoprojectionsbeyonditsback.Thebaseplateisattachedtothemain bodyandanadjustablebladeisattachedtothecircularplatecontainingvernierscale. – Themainscaleisgraduatedindegreesfrom0°to90°inboththedirections.Theadjustablecanbemadeto rotatefreelyaboutthecenterofthemainscaleanditcanbelockedatanyposition. – Formeasuringacuteangle,aspecialattachmentisprovided.Thebaseplateismadefiatformeasuringangles andcanbemovedthroughoutitslength.Theendsofthebladearebeveledatanglesof45°and60°. – Themainscaleisgraduatedasonemainscaledivisionis1°andvernierisgraduatedinto12divisionsoneach sideofzero.Thereforetheleastcountiscalculatedas OneMainscaledivision Leastcount= -------------------------------------- Numberdivisionsonvernierscale = 1/12(Degrees) =(1/12)x60=5Minutes Thus,thebevelprotractorcanbeusedtomeasuretoanaccuracyof5minutes. Applications of bevel protractor: Thebevelprotractorcanbeusedinthefollowingapplications. 1 . F o r c h e c k i n g a ‘ V ’ b l o c k : 2 . F o r m e a s u r i n g a c u t e a n g l e : 3 . F o r c h e c k i n g i n s i d e f a c e o f b e v e l e d f a c e o f g r o u n d s u r f a c e :
• 2.
  SINEBAR - Sinebarsarealwaysusedalongwithslipgaugesasadeviceforthemeasurementofanglesveryprecisely. – Theyareusedto –1. Measureanglesveryaccurately. – 2.Locatetheworkpiecetoagivenanglewithveryhighprecision. – Generally,sinebarsaremadefromhighcarbon,highchromium,andcorrosionresistantsteel.Thesematerials arehighlyhardened,groundandstablished. – Insinebars,twocylindersofequaldiameterareattachedatlieendswithitsaxesaremutuallyparalleltoeach other. – Theyarealsoatequaldistancefromtheuppersurfaceofthesinebarmostlythedistancebetweentheaxesof twocylindersis100mm,200mmor300mm. – Theworkingsurfacesoftherollersarefinishedto0.2 micromilimeter Rvalue. – Thecylindricalholesareprovidedtoreducetheweightofthesinebar. –