Metrology Equipment Catalog - Rapp Industrial Sales

E X T E R N A L M I C RO M E T E R SE X T E R N A L M I C R O M E T E R SPrecision MeasurementThe first micrometer was patented by the Frenchinventor Jean Laurent Palmer in 1848 as “calibre àviset àvernier circulaire”(screw caliper with a circularvernier).The introduction of the micrometer to theindustrial world came about by the visit of twoAmerican engineers, Joseph R. Brown and LucianSharpe to the Paris Exhibition in 1867.At that time, their attention was drawn to Palmer’sinvention, which greatly interested them. After makingsome improvements to the design, Brown &Sharpe received a U.S. Patent in 1899 for amechanical direct reading micrometer. The productwas manufactured on a large scale and marketedsuccessfully by the two partners. Today, Brown &Sharpe continues to make external micrometers withthe same features.With very few exceptions (e.g. externalmicrometers for gear tooth measurements),our micrometers respect the Abbe principle.Spindles are ground on modern grindingmachines and the profile of the screw is accuratelyrestored with negligible pitch deviations.Such manufacturing conditions are the guaranteefor very low measurement uncertainties.Brown & Sharpe, TESA and ETALON premiumbrands are durable and dependable.Max. permissible errorsMeasuring Max. perm. Number of interference µm 10 Nrange/mm errors*/µm fringes or rings0 - 25 4 6 225 - 50 4 6 250 - 75 5 10 375 - 100 5 10 3100 - 125 6 3125 - 150 6 3150 - 175 7 4175 - 200 7 4200 - 225 8 4225 - 250 8 4250 - 275 9 5275 - 300 9 5300 - 325 10 5325 - 350 10 5350 - 375 11 6375 - 400 11 6400 - 425 12 6425 - 450 12 6450 - 475 13 7475 - 500 13 7* The max. perm. errors include the errors of the measuring element as well as the deviations inflatness and parallelism of the measuring faces and the errors due to the flexure of the frame.B-2Rapp Industrial Sales888 789-7277