problem1)a) describe the working of a Parkinson’s rolling gear tester with a sketch.
b) Define effective diameter of a screw thread. What is the difference between effective diameter and pitch diameter in screw threads? Derive the equation for the effective diameter of an external V-thread using 3 wires.
problem2)a) describe the method of determining flatness using optical flat.
b) Define: Tolerance, Allowance, Best-size wire and linearity.
problem3)a) describe the working of Sigma comparator with a neat sketch.
b) List four advantages and four limitations of Mechanical comparator.
problem4)a) In measuring the effective diameter of a 24 mm x 3 mm pitch metric plug screw gauge, the average of the readings taken were:
Micrometer reading over the standard and wires ... 12.9330mm
Micrometer reading over the gauge and wires ... 12.1100mm
Diameter of cylindrical standard =22.0010 mm
Diameter of wires ...1.7320 mm
find out the effective diameter.
problem4)b) Define: V-thread, pitch angle, helix angle and surface roughness.
problem5)a) Derive an equation for overall magnification of pneumatic comparator for 2% error in linearity
b) describe with a sketch the method determining the profile of a spur gear tooth
problem6)a) Compute the limit dimensions for an interference fit on the hole basis system,for a basic size of 20mm diameter, with a negative clearance of 0.100mm, tolerance on the hole is 0.025mm and tolerance on the shaft is 0.050mm. Verify the answer obtained using the definition of interference fit.
b) describe with a sketch the working of Solex Pneumatic comparator.