DML Test Questions And Answers 2022/2023

If the cutting speed (CS) for low-carbon steel is 9-, and the formula for rpm is (CSx4)/D, what should the rpm of the spindle of a drill press be for a 1/8 in diameter high-speed twist drill? For a .750 in diameter drill? - Answer - The rpm for the 1/8in twist drill should be 2880, and for the 3/4-in. drill, 480 If the two drills in question 1 are used in a lathe instead of a drill press, what should the rpm of the lathe spindle be for both drills? - Answer - They would be the same If, in question 2, the small drill could not be set at the calculated rpm because of machine limitations, what could you do? - Answer - Use the next-lower speed setting or the highest setting on the machine if the calculated speed is higher than the top speed An alloy-steel 2-in -diameter cylindrical bar having a cutting speed of 50 is to be turned on a lathe using a high-speed tool. At what rpm should the lathe be set? - Answer - 100 rpm A formula for setting the safe rpm for an 8-in grinding wheel, when the cutting speed is known, is rpm = (CSx4)/D. If the safe surface speed of a vitrified wheel is 6000 sfpm, what should the rpm be? - Answer - The rpm should be 3000 Are feeds on a drill press based on inches per minute or inches per revolution of the spindle? - Answer - inches per revolution (ipr)` Which roughing feed on a small lathe would work best, .100 or .010 per revolution of the spindle? - Answer - 0.010 ipr What kind of machine tool bases feed on inches per minute instead of inches per revolution? - Answer - milling machines, both vertical and horizontal Approximately what should the feed rate be on a 3/4 in-wide grinding wheel on a surface grinder? - Answer - About 1/4-in per table stroke What is the recommended feed rate for drills over 1 inch in diameter? - Answer - .015 to .025 in per revolution When are the lower cutting speeds recommended? - Answer - Lower cutting speeds are used to machine hard materials, tough materials, and abrasive material; on heavy cuts and to get max tool life.