DML HW Questions for Final Test

What is the difference between turning and facing? - Turning: Generation of cylindrical surfaces oriented parallel to workpiece axis Facing: Generation of cylindrical surfaces oriented perpendicular to workpiece axis What is chamfering? - Tool is used to cut an angle on the corner of a cylinder How many axes of motion are there on a lathe, and what are they? - 2; X (perp to lathe) and Z (parallel to lathe) What is the difference between face milling and end milling? - Face milling: Milling flat surfaces at right angles to axis of rotation of the cutter End milling: Can be used on vertical and horizontal milling machines for facing, slotting, and profiling From what material are most milling cutters and drills made? - High Speed Steel What is the most common type of work-holding device for a milling machine? - Vise How many axes of motion are there on a milling machine? - 3; Z is aligned with the spindle axis Define drilling - The process of producing machined holes What is reaming? - Enlarging a previously drilled hole. It provides higher tolerance and improves surface finish What is tapping? - Providing internal threads on a previously drilled hole What is centering? - Used for accurately locating a hole to be drilled afterwards What is the difference between counterboring and countersinking? - Counterboring: Produces a larger step in a hole to allow a bolt head to be seated below part surface Countersinking: Similar to counterboring, but the step is angular to allow flat-head screws to be seated below part surface What is nominal size? - Size used for general description (Ex: 3/4 in shaft) Give an example of bilateral tolerance - It expresses tolerance using plus and minus variations from given size Ex: 1.000 +- 0.002 in Give and example of a limit dimension - Gives upper and lower permitted sizes for a single feature Ex: .998-1.002 What is a clearance fit? - A fit in which one part easily fits into another with a resulting clearance gap Tolerance = (smallest hole)-(biggest shaft) What is an interference fit? - A fit in which one part must be forcibly fitted into another What are 10 things that are essential to every detail drawing? - 1. Dimensions necessary to locate every feature on the part 2. Tolerances for every dimension on the drawing 3. Unit specification 4. Material specification 5. Quantity of parts to be made 6. Surface finish specifications for every surface 7. Appropriate hole and thread notes 8. Unique part name and part number 9. Names of designer and drawer 10. Additional notes about breaking sharp corners, etc. What is the difference between accuracy and precision? - Accuracy: How close a measured value is to the actual value Precision: How close the measured values are to each other What 4 things should every BOM include? - 1. Part numbers 2. Part quantities 3. Part descriptions 4. Unique item numbers that match the corresponding balloons on the drawing Fill in the following unit conversions: 1 inch = ____ mm 1 mm = ____ in 1 m = ____ ft 1 lb = ____ N 1 kg = ____ lb - 1 inch = 25.4 mm 1 mm = 0.0394 in 1 m = 3.28 ft 1 lb = 4.45 N 1 kg = 2.2 lb What is the functional difference between a bolt and a screw? - Bolts have external threads that accept a non-tapered nut Screws have external threads that are threaded into the material they will hold (do not mate with a nut) Regardless of country of origin, what are the two varieties of fastener threads available? - Coarse and fine How are threads on all quality fasteners made and why are they made this way? - They have rolled threads. Rolled threads produce superior surface finish and improved material properties from cold working the material. Rolled threads result in higher fatigue resistance