Chapter 9: Knowledge Check

Check Your Knowledge: Chapter 9

Quiz yourself using the following chapter review questions to check how well you can recall the material.

Review Questions

1. True or false: Machinists need to be aware of rotating hazards on milling machines and take the necessary precautions to eliminate danger.
2. Use the correct term to complete the sentence. The __________ is used to raise and lower the work on the milling machine.
3. Use the correct term to complete the sentence. The solid __________  gives a precise vertical surface that is perpendicular to the base.
4. This component uses flexibility to clamp onto a tool as the drawbar pulls them up into the taper of the spindle.
   1. Spring collett
   2. Drill chuck
   3. Morse taper
   4. End mill holder
5. This tool has many indexable carbide inserts that are designed to cut the top of the work.
   1. End mill
   2. Boring head
   3. Slitting saw
   4. Face mill
6. When is a facing operation typically performed on a part to be milled?
7. What is a critical step performed on the part in between the machining of each face?
8. In what direction should roughing cuts be made while side milling on a manual milling machine?
9. What would be an appropriate first tool when cutting a slot?
10. What would the cutting process look like in order to mill a pocket?
11. What is the quickest way to create an angled feature on a milling machine?
12. What step of creating a radius will help the operator cut the feature to the correct depth?
13. How should the boring head be advanced into the work during a boring operation?
14. In what direction should a slitting operation be performed?
15. What is the simplest form of indexing?

Answer Key

1. True – Nice work! Rotating cutting tools can be especially dangerous if the operator does not recognize the potential dangers.
2. knee – Great job! The knee of the milling machine allows for accurate up and down movement by way of a hand crank. One turn of the hand crank will raise or lower the knee by .100.
3. jaw – Great job! The solid jaw gives a precise vertical surface that is perpendicular to the base and often aligned with the side-to-side motion of the table.
4. Spring collett – Correct! Spring Collets use flexibility to clamp onto a tool as the drawbar pulls them up into the taper of the spindle.
5. Face mill – Correct! A modern day face mill has many indexable carbide inserts that are designed to cut the top of the work. This cutting action is called facing. Face mills can be as small as 1″ in diameter or as big as 10″or larger.
6. Face milling is often the first operation performed on raw material.
   Facing is often done first to establish the overall shape of the part, as well as creating a flat surface that will be used as a reference for other feature depths.
7. The part must be properly deburred.
   If the burrs created by the previous facing operation are allowed to remain on the part, they will interfere with the part being held properly, resulting in a part that is not square.
8. Heavy roughing cuts should be made in a direction that is consistent with conventional milling.
   Conventional milling moves the work against the rotational  motion of the cutter, keeping the backlash out of the movement of the machine. If climb milling is attempted on deep cuts, the backlash may allow the work to be uncontrollably advanced into the cutter causing damage to the tool and/or part.
9. A roughing end mill, one size smaller than the slot.
   A precision slot requires a majority of the material to be removed quickly and efficiently, leaving 1/64” to 1/32” on floors and walls respectively
10. The process of cutting a pocket consists of two main operations. Removing the majority of the material through roughing, and finishing the sides and bottom of the pocket through finishing.
    The roughing operation is done more aggressively to be efficient. The aggressive nature of roughing is not very precise. The finishing operation is conducted in a more delicate manner so that the feature can be created within tolerance.
11. The quickest way to create an angled feature on a milling machine is by holding the part in a vise at an angle.
    Holding the part in a vise at an angle is the quickest and can often be accomplished by using angle blocks. For added precision, dialing in the parts using trigonometry and a drop indicator is a popular method. Adjusting the milling head for just a few parts can be unnecessarily cumbersome.
12. Touching off the tool to the work allows the operator to correctly machine the radius feature
    Touching off the tool establishes the maximum distance the tool should be advanced into the work. Without this step the feature might either be cut too shallow, and not a complete radius, or cut too deep, creating unwanted steps at the ends of the radius.
13. The boring head should be advanced into the work using the quill feed mechanism.
    Boring is an operation that is created with a single point tool. If not precisely controlled and timed with the rotation of the spindle, the surface finish and accuracy of the hole will be poor.
14. The slitting saw should utilize conventional milling cuts.
    If climb milling is used while slitting, automatic advancement of the work can occur, increasing the CPT rapidly, causing catastrophic failure of the saw.
15. Direct indexing is the easiest form of indexing.
    Although there is “simple indexing”, it is much more difficult to calculate and perform than that of direct indexing. Direct indexing allows the operator to quickly make basic indexes in increments of 15 degrees directly on the spindle.