Flashcards
Unit 40, 41, 42, 43 review questions page 319, 323, 331
Cards in this deck (50)
- 1Name three materials used to manufacture drills and state the advantage of any two.carbon tool steel - hobby shops
HSS steel - twice as fast as carbon steel
cemented carbides - for hard material. three times as fast as HSS - 2Define the body, web, and point of a twist drill.BODY: portion of drill between the point and the shank
WEB: Thin partition in the center of the drill that extends the full length of the flutes
POINT: The tip of the drill, consists of the chisel edge, cutting edge, heel and body clearance - 3State the purpose of this part: TangOn the end of a tapered shank to prevent the drill from slipping while it is cutting and allows the drill to be removed without the shank being damaged
- 4State the purpose of: FlutesThey form the cutting edges, admit cutting fluid and allow the chips to escape from the hole
- 5State the purpose of: Marginit is the narrow raised section on the body of the drill. its purpose is to provide a full size to the dill body and cutting edges
- 6State the purpose of: Body clearanceit is the undercut portion of the body between the margin and the flutes. it is made smaller to reduce friction between the drill and the hole.
- 7Why are various drill points and clearances used for drilling operations?to suit the wide variety of materials drilled
- 8Describe and state the purpose of the following drill points: Conventional118 degrees
general purpose drilling - 9Describe and state the purpose of the following drill points: long angle60 to 90 degrees
used for drilling non ferrous materials - 10Describe and state the purpose of the following drill points:: flat angle135 to 150 degrees
used to drill hard and tough material - 11Why is it necessary to thin the web of a drill?to reduce pressure and heat while drilling
- 12List four systems of drill sizes and give the range of each.Fractional drill sizes
Number drill sizes
Letter drill sizes
Millimeter (metric) drill sizes - 13State the purpose of the high-helix drillfor drilling deep holes in aluminum, copper, die cast material and other material where the chips have a tendancy to jam in a hole
- 14State the purpose of the Core drillhas three or four flutes. used to enlarge cored, drilled or punched holes.
- 15State the purpose of the Oil hole drill?has one or two oil holes to force oil to the cutting edge cooling the drill and forcing chips out
- 16State the purpose of the Straight-fluted drillfor drilling soft materials like brass copper or plastic. straight flutes prevent the drill from drawing itself into the material while cutting
- 17State the purpose of the gun drill.used for producing holes as deep as 20ft
- 18State the purpose of the hard-steel drillused for drilling hardened steel
- 19What problems generally result from the use excessive speed and excessive feed?excessive speed = wear at corners of drill
excessive feed = breakdown of chisel point and cutting edges/lips - 20Discuss excessive lip clearance and insufficient lip clearance.excessive clearance = lack of support behind cutting edge
insufficient clearance = causes drill to rub behind the cutting edge - 21What is the effect of drills with unequal angles on the cutting lips?one cutting edge works harder than the other causing bellmouth holes and poor tool life
- 22What is the effect of drills with cutting lips unequal length?produces oversize holes
- 23What are the characteristics of a properly ground drill?both cutting lips should be same length
both cutting lips should be same angle
lips free from wear or nicks
no sign of wear on the margin - 24Unit 41: Why is it important that a drill be operated at the correct speed?Placeholder
- 25explain the difference between cutting speed and r/min.Placeholder
- 26What factors determine the most economical drilling speed?Placeholder
- 27Calculate the r/min required to drill the following holes using a high-speed drill: A 3/8 in diameter hole in tool steelplaceholder
- 28Calculate the r/min required to drill the following holes using a high-speed drill: A 1-inch diameter hole in aluminiumplaceholder
- 29Calculate the r/min required to drill the following holes using a high-speed drill: a 9 mm hole in steel casingplaceholder
- 30Calculate the r/min required to drill the following holes using a high-speed drill: a 20 mm hole in cast ironplaceholder
- 31What is the purpose of a cutting fluidPlaceholder
- 32Name four important qualities that a cutting fluid should have?Placeholder
- 33Select three of the most important safety suggestions and explain why they should be observed?Placeholder
- 34What result might be expected from too high a drill speed?Placeholder
- 35What results might be expected from too low a drill speed?Placeholder
- 36Why is it good practise to start each hole with a center drill?Placeholder
- 37State three reasons a center drill should be removed from the work frequently.Placeholder
- 38Why should center holes not be drilled too shallow?Placeholder
- 39Why should center holes not be drilled too deep?Placeholder
- 40What is the purpose of spotting a hole before drilling?Placeholder
- 41How deep should each hole be spotted?Placeholder
- 42What is the purpose of fastening a clamp or table stop to the left side of the drill press table?Placeholder
- 43When should drilling pressure be eased?Placeholder
- 44List the procedure for laying out a hole before drilling to a layout?Placeholder
- 45How deep should the hole be drilled before the drill point indentation is examined?Placeholder
- 46Explain how a drill may be drawn over to a layout.Placeholder
- 47List three disadvantages of a thick web found on large drills.Placeholder
- 48What are pilot holes and why are they necessary?Placeholder
- 49Why should pilot holes not be drilled any larger than necessary?Placeholder
- 50How high should the drill press table be adjusted when drilling large holes?Placeholder