Term
| What is meant by the cutting speed of a saw? |
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Definition
| The cutting speed for power hacksaws ranges from about 35 to 150 cutting strokes per minute, depending on the make and type of machine. |
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Term
| What is meant by the feed rate of a saw? |
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Definition
| The movement of the tool into the work piece with each stroke or revolution. |
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Term
| Describe how short pieces can be safely held in the vise for cutoff. |
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Definition
| Place another piece of the same size on the opposite side of the vise. Then the vise jaws stay parallel. |
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Term
| What kinds of cuts or other operations can be performed on a vertical band saw? |
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Definition
| Band filing, band polishing, band sawing, straight line cuts, angular cuts, curved line cuts internal contour cuts. |
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Term
| How can the cutting speed be changed on your vertical band saw? |
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Definition
| On most band saw the speed is changed by changing the position of the V-belt on the motor and machine drive pulleys. Some also have a variable-speed drive mechanism. |
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Term
| Recommended cutting speeds for band sawing vary according to four important factors. Name them. |
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Definition
| The kind of material being cut, the hardness of the material, the thickness of the material, and whether the cutting is wet or dry |
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Term
| What is the recommended band-saw cutting speed for low-carbon steel ¾” thick without cutting fluid? With cutting fluid? |
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Definition
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Term
| Name the two kinds of band-saw blade tooth set, and give the recommended use for each. |
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Definition
| Raker and wavy. Raker set is recommended for most contouring cuts in vertical machines. The wavy set is recommended for most operations on horizontal machines and for cutting thin metals or thin-wall tubing. |
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Term
| Name the main parts of a drill press |
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Definition
| Speed control handle, switch, quill, spindle, feed handle, table lock, table, table positioning handle, column, base and t-slot. |
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Term
| What is meant by automatic feed? |
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Definition
| The machine uses power to force the drill into the metal. |
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Term
| How is the speed of a drill press changed if it has a cone pulley drive system? Variable-speed drive system? |
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Definition
| The back gears, located inside the front pulley, give additional speeds. With this drive system, you must stop the motor before shifting gears. a variable speed drive gives a continuous range of speeds shown on a dial. It is adjusted only while the drill is running. |
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Term
| Name the three kinds of drills. Which one is used most for metalwork? |
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Definition
| Twist drill, straight fluted drill, and the spade drill. The twist drill is used most for metalwork. |
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Term
| Name three kinds of materials used for making drills. |
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Definition
| Carbon steel, high speed steel, and tungsten carbide. |
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Term
| What purpose do the flutes of a drill serve? |
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Definition
| To help form the cutting edges at the point, to form passages for the chips to come out of the hole, and to allow the cutting fluid to travel to the cutting edges of the drill. |
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Term
| What is the name of the taper used on tapered-shank tools? |
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Definition
| The American Standard (Morse) Taper |
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Term
| Drills are made according to four different size systems. Name them. |
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Definition
| Number drills, letter drills, fractional drills, and metric drills. |
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Term
| part of the drill should be measured with a micrometer to find its size? |
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Definition
| A new drill should be measures across the margins at the point; a worn drill must be measured at the ends of the flutes near the neck. |
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Term
| Should a small drill run slower than a large drill if they are drilling the same material? |
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Definition
| The smaller the diameter of the drill, the greater should be the speed; the larger the diameter , the slower should be the speed. |
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Term
| How can you tell when a drill is running too fast? |
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Definition
| If the corners of the cutting edges wear away quickly, the speed should be reduced. |
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Term
| Calculate the correct rpm for a ½” drill to cut at 200 fpm. |
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Definition
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Term
| How should a drill chuck or drill sleeve be removed from the drill-press spindle? |
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Definition
| The drill or drill chuck should be removed from the drill-press spindle with a drill drift. |
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Term
| What is a center drill? What is it used for? |
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Definition
| Center drills are made in several sizes, and are used to establish hole centers for guiding drills. They are also used to provide properly shaped bearing surfaces for metal lathe centers. |
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Term
| Why are twist drills somewhat dangerous to use when drilling holes that go completely through a work piece? |
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Definition
| A twist drill that is just breaking through the bottom of the hole acts just like a corkscrew. This can cause a dangerous situation. The drill may grab and break off or the work may be torn loose from its holdings. |
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Term
| What is the main reason why reamed holes are sometimes more desirable than drilled holes? |
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Definition
| Machine holes rounder, straighter, and more accurately to size than drills. |
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Term
| How much metal should be left for a hand reamer cuts. Does a hand reamer cut the same way? |
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Definition
| Never take cuts greater than .005” with a hand reamer. |
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Term
| What is meant by countersinks? |
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Definition
| There are several kinds of countersinks. The difference in them is the angle of the cutting edges. |
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Term
| What is the difference between countersinking and counterboring? |
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Definition
| Countersinking is done with a countersink, while counterboring is done with a cutting tool known as a counterbore. |
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Term
| How can you find out what size tap drill to use? |
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Definition
| By looking up the size on a drill size chart. |
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Term
| What kinds of parts are made on metal working lathes? Give several examples |
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Definition
| Used for making single parts and small quantities of identical pars, or for repairing worn parts. |
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Term
| Name two main uses for the lathe tailstock. |
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Definition
| The tailstock can be clamped at any point along the bed to the right of the headstock. The tailstock spindle does not turn; however, it can be moved in and out of the tailstock with the tailstock hand wheel. |
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Term
| What is meant by longitudinal feed on a lathe? |
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Definition
| When the tool is fed along the work, parallel to the lathe bed. The longitudinal fed is used for operations such as turning and boring. |
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Term
| What is meant by cross feed on a lathe? |
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Definition
| tool is fed across the end of the work piece as in facing operations. |
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Term
| What is meant by feed rate on a lathe? |
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Definition
| The distance that the tool moves along the work piece during one revolution of the work piece. |
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Term
| What is the name of the lever that selects longitudinal or cross feed?(lathe) |
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Definition
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Term
| What is the name of the control that reverses the direction of the power feed?(lathe) |
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Definition
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Term
| What is a lathe dog used for? |
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Definition
| Keeps the work piece form slipping during lathe operation. |
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Term
| What is a steady rest used for? |
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Definition
| Used to support work pieces for machining. |
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Term
| Explain how to center a work piece with the use of a dial indicator. (Lathe) |
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Definition
| Contact the work piece with the dial indicator in line with the chuck jaw that is farthest off center. Then advance the cross slide by turning the cross feed knob until the dial pointer has moved almost one revolution. |
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Term
| Name five forms in which abrasives are used in metalworking. |
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Definition
a. Abrasive cloth
b. Loose grain and powder abrasive
c. Abrasive compounds
d. Grinding wheels
e. Sharpening stones |
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Term
| Explain how abrasive grain size is determined |
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Definition
| Number of holes per lineal inch in a siev, or screen , thus a 10 grain abrasive is one that will pass through a 10 mesh screen . a 10 meshes per inch or 100 meshes per square inch. |
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Term
| What is lapping? What is it used for? |
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Definition
| Lapping is the removal of small amounts of metal from a hardened steel surface. It is done when ordinary grinding would remove too much metal, especially on measuring tools where smooth surfaces and exact sizes are needed. |
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Term
| Name several reasons for grinding |
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Definition
a. To sharpen cutting edges on drills, milling cutters, taps and other cutting tools made from hardened steel and other hard metals.
b. As a machining process to cut metal to its desired shape and size.
c. To make smooth, polished surfaces such as those required for bearings and on rolls for processing various materials. |
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Term
| Name the two abrasives most used for making grinding wheels. |
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Definition
| Aluminum oxide and silicon carbide |
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Term
| What is meant by the structure of a grinding wheel? |
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Definition
| The spacing between the abrasive grains. |
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Term
| List the information needed to order a grinding wheel for your shop. |
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Definition
Type of grinding operation
Material to be ground
Amount of stock to be ground
Quality of finish desired
Area of wheel contact
Wheel speed
Whether grinding is done dry or with a cutting fluid. |
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Term
| What are utility grinders? What are they used for? |
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Definition
| used for non precision grinding operations done by hand. removal of burrs and other sharp edges; removal of flash and other casting imperfections; preparations of joints for welding; smoothing of welds; and sharpening of cutting tools. |
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Term
| What is a tool rest used for? How close should it be set to the wheel? |
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Definition
| Where work is rested while grinding, as close as possible without touching the grinder. |
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Term
| What is a grinding wheel flange? What is its purpose? |
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Definition
| a. Large metal washers placed on each side of the grinding wheel. They clamp the wheel in place on the shaft and hold the parts of the wheel together if it breaks. |
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Term
| What is a safety washer’s purpose? What is it made of? |
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Definition
| a. Soft washers made of blotting paper, leather, or rubber should be placed between the wheel and the flanges. They are slightly larger than the flanges. The soft material is forced into the pores of the wheel, thus locking the wheel in place between the flanges. |
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Term
| How should a grinding wheel be inspected for cracks? |
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Definition
| a. While supporting the wheel on a wood dowel through its hole, strike the wheel gently with a light object. Use the handle of a screwdriver for light wheels and a mallet for heavy ones. A good wheel with ring clearly when struck. |
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Term
| What is meant by the surface of speed of a grinding wheel? |
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Definition
| The speed of the rim of the wheel and the distance it would travel if rolled on the floor for one minute. |
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Term
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Definition
| One that has become clogged with bits of metal or other material. |
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Term
| What is meant by dressing a wheel? |
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Definition
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Term
| What is meant by truing a wheel? |
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Definition
| Cutting the wheel so that there will be no high spots when the wheel is running. |
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Term
| What is meant by “burning the temper”? How can it be avoided? |
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Definition
| a. The tool is being burnt when it turns to a purple or blue color. This causes the steel to lose its temper; that is , it loses some of its hardness. |
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Term
| Why should only the face of the grinding wheel be used for grinding? |
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Definition
| To keep the wheel surface flat |
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Term
| What does burnishing mean? How is it done? |
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Definition
| Burnishing means to make smooth and bright by rubbing with something hard and smooth. |
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Term
| Tell how electroplating is done. |
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Definition
| A direct current is passed from a pure copper plate to the work piece through a copper sulphate solution, this removes copper from the anode and deposits copper on the cathode. The thickness of the plating depends on how strong a current is used and how long the work piece is left in the plating bath. |
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Term
| What buffing compounds are used for polishing aluminum? Brass? Steel? |
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Definition
Aluminum- tripopli -rouge
Brass-tripoli- lime
Steel-400 silicon carbide-rouge |
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Term
| Tell how the work piece should be held for safe buffing. |
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Definition
| Hold the work on the underside of the front of the wheel. |
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Term
| Why is it important for work pieces to be accurately positioned, solidly supported, and clamped? |
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Definition
| a. If the work piece springs or moves while it is being machined, the cutting tool may break. And the work piece may be thrown from the machine |
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Term
| What are T-slots? What is their purpose? |
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Definition
| Slots through which bolts may be slipped for clamping vises and work pieces. |
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Term
| Describe how V-blocks are used in setup work. |
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Definition
| Used to hold round work. They should be made or purchased in pairs so that one can be placed under each end of long work. They are made with or without matching clamps. |
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Term
| What are fixtures? In what way do they differ from jigs? |
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Definition
| a. Workpiece-holding devices used to hold odd-shaped workpieces. They are used in production work to enable a worker to quickly support and clamp a workpiece for machining. |
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Term
| What kind of oil should be used for lubricating machines? |
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Definition
| Mineral oils and animal oils |
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Term
| Why are greases used instead of oils in some cases? |
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Definition
| They can be sealed better against loss, they protect against entrance of dirt and moisture, and they tend to cling better to some surfaces. |
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Term
| What is meant by the viscosity of oil? How is it measured? |
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Definition
| a. The stiffness or thickness, measured by the length of time in seconds that a standard amount of oil at a certain temperature can flow through a hole. |
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Term
| List two ways of getting grease to the point of lubrication |
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Definition
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Term
| List the ways in which cutting fluids improve the machining of metals. |
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Definition
a.Cool the cutting tool and the work
b.Lubricate the face of the cutting tool and the chip
c. Prevent the adhesion, or pressure welding, or a built-up edge on the cutting tool.
d.Aid in flushing away chips
e.Improve the quality of the machined surface
f.Increase tool life by reducing tool wear
g.Permit higher cutting speeds than those used for dry machining. |
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