Section 6, Unit 1 1.
What part of the vertical milling machine allows workpieces to be raised and lowered? Knee
2.
Briefly describe the direction of movement provided by the saddle. The saddle permits movement toward and away from the column along the “Y” axis.
3.
When a table handle is turned clockwise the table moves away from the operator position.
4.
What distance does the saddle or table usually move when a handle is rotated one full turn? .200”
5.
List three items that should not be placed on a milling machine table. Cutting tools, hammers, files, wrenches, or other rough tools on the machine table.
6.
Briefly describe the function of the turret and the ram of a vertical milling machine. The top of the column casting is a machined flat surface. The turret rests on this surface and allows the entire machine head to be swiveled 360 degrees. The ram allows the entire head to be moved forward and backward and then locked in position. This movement is provided to increase the workpiece capacity of the machine.
7.
What is the name of the taper found in most modern vertical milling machines? R-8
8.
What part of the vertical mill can be raised and lowered to position cutting tools or used to feed tools during holemaking operations? Quill / Quill feed handle
9.
How can power quill feed be automatically stopped when feeding in a downward direction? By positioning the micrometer adjusting nut so the quill stop comes in contact with it.
10.
What is a benefit of using a DRO instead of micrometer collars for positioning on a vertical milling machine? Eliminates backlash error and many can be programmed to aide in creating bolt hole circles and calculate trig functions.
Section 6, Unit 2 1.
Many of the cutters found in the tool room are made of either HSS (High speed steel) or Carbide.
2.
What type of cutting tool would most likely be used to machine the special long slots in a milling machine table? “T – Slot”
3.
Which type of cutter would most likely be used to machine a half-moon-shaped slot into a shaft to accommodate a key to secure a flywheel? Woodruff Keyseat Cutter
4.
What workpiece factors might cause a four-flute endmill to be selected over a two-flute endmill for an application? Material being cut and the cutting conditions.
5.
List three types of milling cutters that are used to machine the top surface on the workpiece flat: Fly cutter, Shell endmill, & Face mill.
6.
Most manual vertical milling machine spindles are equipped with what style of taper? R-8 shank
7.
A drawbar is used to retain the tool-holder arbor in the milling machine spindle.
8.
What type of tool holder might be selected for mounting a slitting saw? Stub arbor
9.
Sketch a corner-rounding endmill. (sketch may vary)
10.
What toolholding device uses two drive keys and a pilot diameter to mount large milling cutters? An R-8 shell mill holder
11.
List two workholding applications where hold-down clamps would be best: When the size or shape of a part makes it difficult to hold in a vise but the volume of work does not justify the expense of creating a custom fixture.
12.
List the four basic pieces of a step clamp set: T-nuts, studs of various lengths, clamps of various lengths, riser blocks of various heights, and necessary nuts and washers.
13.
When using step clamps, how should the clamp straps be positioned for best clamping? The T-nut and stud are close to the work. The back of the clamp is slightly raised by the riser block to direct clamping pressure toward the work. The stud length provides adequate thread engagement in both the T-nut and clamping nut.
14.
Irregularly shaped work may be held in a custom workholding device called a(n) fixtures.
Section 6, Unit 3 1.
List five safety guidelines to observe when operating the vertical milling machine. Answers will vary. Always wear safety glasses when operating a milling machine; Wear appropriate hard-soled work shoes; Wear short sleeves or roll up long sleeves past the elbows; Do not wear any loose clothing that can become caught in moving machine parts; Remove watches, rings, and other jewelry; Secure long hair so it cannot become tangled in moving machine parts; Make sure all machine guards and covers are in place before operating any milling machine; Never operate a milling machine that is locked out or tagged out, and never remove another person’s lock or tag; Be sure all cutting tools and workpieces are secure before beginning any machining; After tightening or loosening a drawbar, remove the drawbar wrench immediately; Get help when moving heavy workpieces or workholding devices and use proper lifting techniques; When operating a milling machine, stay focused on the machine. Do not become distracted by other activities or talk to others; Never walk away from the mill while it is running; Do not let others adjust work, tool, or machine settings, and do not adjust other people’s setups; Keep the machining area clear of all items including rags and tools to ensure that nothing comes in contact with rotating cutting tools. Items can become entangled in cutting tools or be violently thrown from the work area if they touch a rotating cutting tool; Always shut off the spindle and let it come to a complete stop before adjusting workholding or tool holding devices or to take measurements or clean the machine; Use caution when handling milling cutters so sharp edges do not cause cuts; Remove chips from the workpiece and tool using a brush only after the spindle has come to a complete stop. Never remove chips by hand; Never use compressed air to clean chips, debris, and cutting fluids from the mill.
2.
Briefly describe the process of aligning a milling vise with the table movement using a dial indicator. To align a vise, first be sure both the machine table and bottom of the vise are clean and burr free. Gently place the vise on the machine table and position the clamps. Using a dead blow hammer to tap the vise during alignment. Make adjustments until the TIR is 0.0005" or less. Recheck TIR after fully tightening the clamps.
3.
What is chip load? FPT (feed per tooth) is also called IPT (inches per tooth) or chip load. It is the thickness of the chip removed by one cutting edge of the tool per each revolution of the cutting tool. FPT values are small and generally range from around 0.0005" to 0.010".
4.
Define IPM. Inch per minute.
5.
Calculate spindle speed and feed for the two following situations: a. Use a HSS 1/2”-diameter three-flute endmill to mill 6061 aluminum 350 SFPM using a .0015” chip load. 2674 RPM 12.033 Feed b. Use a carbide 3”-diameter eight-tooth shell to face mill H13 tools steel at 200 SFPM using a .003” chip load. 254 RPM 6.112 Feed
6.
Briefly describe the steps to use an edge finder to locate the edge of a workpiece. To find the center of an existing hole a dial indicator is often used. First, visually locate the spindle in the center of the hole by moving the table and saddle. Mount a dial test indicator in the spindle and place the spindle in neutral. Zero the dial face when the indicator is in line with one machine axis. Then rotate the spindle 180 degrees and note the difference in the indicator readings. The table needs to be moved one-half of the indicator reading to center the spindle in the hole. Then do the same for the following axis.
7.
What are two benefits of boring over other holemaking operations? Any desired hole size can be machined and large-diameter holes that are beyond the range of drills and reamers can be produced. Another benefit of boring is the ability to adjust the location of a hole since the boring tool will not follow the existing hole like a drill.
8.
What are face milling and peripheral milling? Face milling is using the face of a cutting tool to machine a surface, peripheral milling is using the outside periphery of the cutting tool to machine a surface.
9.
When squaring a block on the vertical mill, what surface of the block should be machined first, and why? The largest surface of the workpiece should be machined first to create a flat reference surface that will then be used to machine other surfaces. Using the largest surface will minimize any setup errors when machining other sides of the block. If a smaller surface is used to orient the block for cutting a larger surface, any setup error will be multiplied.
10.
What are the three basic methods used to mill angular surfaces? The workpiece can be angled, the head of the mill can be angled, or an angled milling cutter can be used.
11.
What must first be done before milling with either a T-slot cutter or dovetail cutter? First machine a straight slot with a standard endmill.
12.
What are the two basic types of keys? A plain key and keyseat and a woodruff key and keyseat.
13.
What diameter cutter should be used to create 3/16” radii in the corners of a pocket? 3/8”
14.
When roughing a pocket, machine in a clockwise/counterclockwise direction. Mill roughing passes outward from the center in a clockwise direction to use conventional milling.
Section 6, Unit 4 1.
What is a rotary axis? Rotary table and indexing heads provide circular motion.
2.
Define the term indexing. The dividing head provides the ability to rotate the workpiece in very precise increments. This rotary positioning is known as indexing.
3.
Describe the primary differences between the rotary table and the indexing head. While a rotary table is usually used to rotate the workpiece as it is being machined, the dividing head is mostly used for rotating the workpiece to a position and then securing it there for machining.
4.
Name three types of workpiece features that are well suited to using a rotary positioning device. Multiple angles, locate holes in circular patterns, radii, circles, arcs.
5.
Briefly describe the two alignment steps that need to be performed when setting up the rotary table on the milling machine.
After mounting the rotary table on the mill table, the next step is to align the rotary table center line with the machine spindle center line. The milling machine table position must be adjusted until the indicator contact ball appears to be rotating concentric with the hole in the table. This method is only intended to get the table alignment close. After visually aligning the spindle and rotary table, the indicator can be lowered down into the hole and zeroed. Next, rotate the spindle again by hand. Center the spindle and rotary table within 0.0005". When alignment has been achieved, lock the X- and Y-axes and set the micrometer collars to zero and/or set the DRO to zero. 6.
If the outside of a 6”-diameter disk is to be milled using a rotary table and a ¾” diameter endmill, what is the total amount the milling machine axis must be offset? 3-3/8”
7.
What is the gear ratio found in the gear train of most indexing heads? 40:1 (40 turns of the crank handle are required to rotate the spindle 1 turn).
8.
When using the indexing head, a tailstock is used to support long workpieces during machining.
9.
A workpiece requires 9 divisions. Calculate the correct direct indexing plate and number of notches to advance the plate. Plates with 24, 30, and 36 notches are available. 2.67, 3.33, & 4
10.
In the formula T =
40 , what do T and D represent? D T = number of turns of the crank handle D = number of desired divisions
