Screw Thread Measurement Prof. M. M. Joke Chapter 5 Screw Thread Measurement
Prof. M. M. Joke
Prof. M. M. Joke
Prof. M. M. Joke Errors in Threads Major diameter error – Cause interference with the mating threads or reduction in the flank contact or weakness by reduction of the wall thickness. Minor diameter error - Cause interference with the mating threads or reduction in the flank contact or weakness by reduction of the cross section of the root.
Prof. M. M. Joke Errors in Threads 3.Effective diameter error – Determine the amount of slackness or interference between the flanks of mating threads. 4.Errors or Pitch and Thread angle – Result in progressive tightening and interference on assembly.
Pitch Errors Progressive Error Periodic Error Drunken Error Prof. M. M. Joke Pitch Errors Progressive Error Periodic Error Drunken Error Erratic or Irregular Error
Prof. M. M. Joke
Prof. M. M. Joke
Prof. M. M. Joke
Disturbances in the machining setup. Prof. M. M. Joke Erratic Errors – Vary in an irregular manner along the length of the thread. Their causes are difficult to identify. Possible causes are: Fault in the machine. Irregular cutting action resulting from non-uniformity in the material of the screw. Disturbances in the machining setup.
Measurement of different elements of Thread Prof. M. M. Joke Measurement of different elements of Thread Major diameter Minor diameter Effective diameter Pitch
Prof. M. M. Joke Major diameter
Prof. M. M. Joke Major diameter
Prof. M. M. Joke Bench Micrometer
Prof. M. M. Joke 2. Minor diameter
2. Minor diameter – Internal Prof. M. M. Joke 2. Minor diameter – Internal Use of Taper Parallels
using Thread Micrometer 3. Effective diameter – using Thread Micrometer Prof. M. M. Joke
3. Effective diameter – using wo Wire Method E=T+P Prof. M. M. Joke E=T+P Where, P is a constant, which depends upon the diameter (d) of wire and pitch (p) of the thread. P=0.866p - d
4. Pitch Prof. M. M. Joke
4. Pitch – Tool Makers Microscope Prof. M. M. Joke
4. Pitch – Thread Pitch Gauge Prof. M. M. Joke
Floating Carriage Dial Micrometer – Major, Minor & Effective Diameters Prof. M. M. Joke
Floating Carriage Dial Micrometer Prof. M. M. Joke