Lathe & limts fits Problems.pdf

Limit, fits and tolerance 2 3 4 5 1. Design a GO and NO-GO workshop gauges to check a hole and shaft of assembly 25H7/f8. Allow gauge tolerance of 10% with a wear allowance equal to one fifth of the gauge tolerance. Given that i = 0.45 (D)1/3+0.001D, fundamental deviation of ‘f” = -5.5...

Limit, fits and tolerance 2 3 4 5 1. Design a GO and NO-GO workshop gauges to check a hole and shaft of assembly 25H7/f8. Allow gauge tolerance of 10% with a wear allowance equal to one fifth of the gauge tolerance. Given that i = 0.45 (D)1/3+0.001D, fundamental deviation of ‘f” = -5.5 D 0.41, 25 mm falls in the diameter step of 18 mm and 30 mm, IT7=16i, IT8=25i. 2. Design a GO and NO-GO inspection gauges to check a hole and shaft of assembly 20H7/f8. Allow gauge tolerance of 10% with a wear allowance equal to one fifth of the gauge tolerance. Given that i = 0.45 (D)1/3+0.001D, fundamental deviation of ‘f” = -5.5 D 0.41, 20 mm falls in the diameter step of 18 mm and 30 mm, IT7=16i, IT8=25i. 3. Design a GO and NO-GO general gauges to check a hole and shaft of assembly 30 H7/f8. Allow gauge tolerance of 10% with a wear allowance equal to one fifth of the gauge tolerance. Given that i = 0.45 (D)1/3+0.001D, fundamental deviation of ‘f” = -5.5 D 0.41, 30 mm falls in the diameter step of 18 mm and 30 mm, IT7=16i, IT8=25i. 4. Design a GO and NO-GO general gauges to check a hole and shaft of assembly 30H7/f8. Allow gauge tolerance of 10% with a wear allowance equal to one fifth of the gauge tolerance. Given that i = 0.45 (D)1/3+0.001D, fundamental deviation of ‘f” = -5.5 D0.4, 25 mm falls in the diameter step of 18 mm and 30 mm, IT7=16i and IT8=25i. 6 Lathe 1. Calculate change gears for cutting L.H. threads of 5 TPI on a lathe having lead screw of 6 mm pitch. Sketch the gear arrangement? 2. Calculate change gears to cut R.H. single start threads of 0.25″ pitch on a lathe having lead screw of 6 mm lead. Give the schematic arrangement of gears in the absence of feed reversing mechanisms. 3. Calculate change gears to cut L.H. single start threads of 0.25″ pitch on a lathe having lead screw of 8 mm lead. Give the schematic arrangement of gears in the absence of feed reversing mechanisms. Machine Tools 8 1. A Mild steel bar of 100 mm long, 50 mm diameter is turned to 45 mm diameter. Assume the workpiece rotates at 200 rpm, feed is 0.1 mm/rev and maximum depth of cut is 1 mm. consider approach and over travel distance as 5 mm for turning operation, Assume that facing operation is also performed for the finished job and estimate the total machining time? 2. Find the time required for one complete cut on a piece of work 350 mm long and 50 mm in diameter. The cutting speed is 35 m/min and the feed is 0.5 mm/rev. 3. A C. I. plate measuring 300 mm×100 mm × 40 mm is to be rough shaped along its wider face. Calculate the machining time taking approach= 20 mm, over travel=5 mm, cutting speed = 15 m/min, return speed = 25 m/min, Allowance on either side of the plate width = 5 mm and feed rate per cycle = 1 mm. 4. A Mild steel bar of 170 mm long, 60 mm diameter is turned to 165 mm long 50 mm diameter. Assume the workpiece rotates at 440 rpm, feed is 0.3 mm/rev and maximum depth of cut is 2 mm. consider approach and over travel distance as 5 mm for turning operation, Assume that facing operation is also performed for the finished job and estimate the total machining time? Machine Tools 9