engleski

Calculation Of Pitch Diameter Of Symetrical Thread Plug Gauges

Most of calibration methods for screw-thread gauges relay on mechanical techniques with spherical or cylindrical probing elements. Main difficulty of pitch diameter calculation arises during determination of coordinates of probing element and screw surface contact. This paper proposes mathematical model for pitch diameter calculation of thread gauges measurements using mechanical probing method (3-wire method). Calculations which are now being used are approximate and some of geometrical parameters are omitted to make such calculations possible. In order to describe complete geometry of thread and probing element, a non-linear equation system has been established and solved numerically. Solution of this system gives actual contact points of probing element with thread profile. Pitch diameter is calculated directly without any further corrections. This mathematical model can be applied on parallel threads without any restrictions regarding lead and flank angles. Calculation of rake-correction is therefore avoided completely.

thread gauges; rake correction; pitch diameter measurements; screw surface; thread measurement methods

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