Machinery Repairman

More documents

Recommendations

Info

Figure 15-5.—Typical structure of low-carbon steel. The structure of an alloy is described as being a MECHANICAL MIXTURE when two or more structural forms are mixed together but are still separately distinguishable. A mechanical mixture of an alloy is comparable-though on a smaller scale-to the mixture of sand and gravel in concrete. One of the most important mechanical mixtures that occurs in many steels is known as PEARLITE. Pearlite, so called because it has a pearly luster when seen under a microscope, is an intimate mechanical mixture of ferrite and cementite in alternate plates or layers. Ferrite is a solid solution, and cementite or iron carbide is an intermetallic compound; in pearlite, the two are closely mixed to form a characteristically layered structure. When the entire structure of the alloy is in the form of pearlite, the composition is referred to as the EUTECTOID COMPOSITION. The pearlitic structure is called the EUTECTOID or the EUTECTOID STRUCTURE. The internal structure of an alloy may show various combinations of pure metals, solid solutions, intermetallic compounds, and mechanical mixtures. Many of the combinations that are important in steels and other alloys are the result of heating and cooling of the alloy. Figure 15-5 shows, very much enlarged, a typical combination that occurs when plain-carbon steel containing less than 0.83 percent carbon is heated to a certain temperature and then cooled slowly. This combination consists of the solid solution ferrite and the mechanical mixture pearlite, each in crystal form, distributed throughout the alloy. The relative proportions of ferrite and pearlite in this combination depend largely upon the carbon content of the alloy. 15-6 Figure 15-6.—Controlled atmosphere electric furnace used for heat-treating. HEAT-TREATING EQUIPMENT The equipment required for heat-treating consists of furnaces or other heating devices, quenching baths or other cooling devices, temperature controls and indicators, and other controls and indicators required for the proper operation of the equipment or for the control of the process. In addition, heat-treating equipment includes tongs and other devices for handling and holding the work while it is being heated or cooled. Because heat-treating equipment varies so widely, it is not practical to describe or to give operating instructions for different types in this course. The equipment described here is typical of heat-treating equipment you may be required to use, but it does not include all possible types of equipment. If you are required to heat-treat metals, find out all you can about the equipment that is available before you begin to use it. The instructions furnished by the manufacturer are usually your best-and sometimes only-source of authoritative information on a specific item of heattreating equipment.
HEATING EQUIPMENT Figure 15-7.—Exploded view of electric furnace used for heat-treating. Equipment designed for the heating of metals includes electric furnaces, fuel-fired furnaces, bath furnaces, and devices for the measurement and control of temperature. Improvised heating devices may include oxyacetylene torches, Hauck burners, forges, and temporary ovens constructed of firebrick and sheet asbestos. We will discuss electric furnaces since they are what most <strong>Machinery</strong> Repairmen will be using. The gases that circulate through the furnace heating chamber and surround the metal as it is being heated make up the FURNACE ATMOSPHERE. By controlling the composition of the furnace atmosphere, you can produce the type of atmosphere best suited for the heating of a particular type of metal. Furnace atmospheres are generally classified as being oxidizing, reducing, or neutral. An OXIDIZING ATMOSPHERE exists when excess air is circulated through the furnace. Some electric furnaces are designed to operate with an oxidizing atmosphere at all times. An oxidizing atmosphere is indicated by bright, clean walls and a clear, transparent atmosphere in the furnace. Metals heated in an oxidizing atmosphere occasionally develop films of metal oxides (scale) on their surfaces. In some cases, this is undesirable; but in other cases, it is desirable because it tends to prevent further decarburization of the metal. Decarburization is a term used to describe the loss of carbon from the surface of ferrous metals with consequent softening of the material. A REDUCING ATMOSPHERE tends to remove oxygen from the surface of the metal. A reducing atmosphere is often desirable in heat treatment since it tends to prevent oxide formation and other surface deterioration. If decarburization of steel is to be 15-7 avoided, however, a neutral atmosphere rather than a reducing or oxidizing atmosphere is used. A NEUTRAL ATMOSPHERE is neither oxidizing nor reducing because it contains no oxygen (oxidizing agent) and no carbon monoxide (reducing agent). In reality, other factors often tend to produce either oxidation or decarburization; therefore, an atmosphere that is described as neutral may not always be totally neutral. The furnace atmosphere may be the result of the deliberate introduction of a gas or a mixture of gases into the heating chamber. When gases are deliberately introduced into the heating chamber for the purpose of controlling the atmosphere, the furnace is said to have a CONTROLLED or PROTECTIVE ATMOSPHERE. Electric Furnaces Electric furnaces with a controlled atmosphere are frequently used for heat-treating on repair ships and tenders. Quite often two such units are used on the same ship. One is a relatively low-temperature furnace used for preheating or tempering, and the other is a higher temperature furnace used for hardening. Both types are equipped with control devices for regulating temperature. The high-temperature furnace may also be equipped with rheostats used to increase the rate of heating. A typical electric furnace for shipboard use is shown in figure 15-6. An exploded view of a slightly different type of electric furnace is shown in figure 15-7. The outer casing of the furnace is usually made of sheet steel. Just inside the casing is a layer of insulating material, such as mica, spun glass, or asbestos. Inside this insulating material is a lining of refractory material, such as firebrick and insulating brick. The refractory lining insulates the furnace, helps maintain the required
Page 1 and 2:
Naval Education and Training Comman
Page 3 and 4:
MACHINERY REPAIRMAN NAVEDTRA 12204-
Page 6 and 7:
PREFACE This Training Manual (TRAMA
Page 8 and 9:
CONTENTS CHAPTER PAGE 1. 2. 3. 4. 5
Page 10 and 11:
Another job description found in pr
Page 12 and 13:
1-2, and 1-3 show some of the commo
Page 14 and 15:
You must know the location of tools
Page 16 and 17:
The correct way to measure an insid
Page 18 and 19:
appropriate sides of the jaws on th
Page 20 and 21:
Dial Bore Gauge The dial bore gauge
Page 22 and 23:
Gear Tooth Vernier Use a gear tooth
Page 24 and 25:
Surface Gauge A surface gauge (fig.
Page 26 and 27:
Figure 1-20.—Center gauge. angle
Page 28 and 29:
accuracy. They generally come in ma
Page 30 and 31:
MICROMETERS is essentially the same
Page 32 and 33:
meanings of these terms and the imp
Page 34 and 35:
number is shown for roughness heigh
Page 36 and 37:
Figure 2-7.—Master roughness scal
Page 38 and 39:
Figure 2-11.—Checking surface fin
Page 40 and 41:
Figure 2-17.—Laying out a 45-degr
Page 42 and 43:
Figure 2-24.—Setting and using a
Page 44 and 45:
Figure 2-29.—Bisecting an angle.
Page 46 and 47:
prick-punch “witness marks” aro
Page 48 and 49:
Figure 2-35.—Filing. The crosshat
Page 50 and 51:
keyway broach requires a bushing th
Page 52 and 53:
The steps involved in repairing a d
Page 54 and 55:
SETTING UP OXYACETYLENE EQUIPMENT T
Page 56 and 57:
GREASE IN THE PRESENCE OF OXYGEN UN
Page 58 and 59:
Strength metal into thin sheets. Le
Page 60 and 61:
and forming into plates, billets, b
Page 62 and 63:
Each of the aluminum alloys has pro
Page 64 and 65:
with an average carbon content of 1
Page 66 and 67:
The manufacturer is required to mak
Page 68 and 69:
with that of known specimens. Many
Page 70 and 71:
Gray cast iron produces a spark str
Page 72 and 73:
Table 3-4.—Major Groups of Plasti
Page 74 and 75:
Lathe Operations Lathe operations a
Page 76 and 77:
mechanism is also attached to the s
Page 78 and 79:
Band Selection and Installation The
Page 80 and 81:
File Bands A file band consists of
Page 82 and 83:
This prevents sagging of the file b
Page 84 and 85:
Figure 4-16.—Butt welder-grinder
Page 86 and 87:
paragraphs contain the procedures f
Page 88 and 89:
Figure 4-22.—Disk-cutting attachm
Page 90 and 91:
Figure 4-26.—Sensitive drill pres
Page 92 and 93:
shops are the Morse taper shank, sh
Page 94 and 95:
Figure 4-30.—Common types of clam
Page 96 and 97:
Figure 4-34.—Two types of counter
Page 98 and 99:
andomly follow the straight sides a
Page 101 and 102:
CHAPTER 5 OFFHAND GRINDING OF TOOLS
Page 103 and 104:
Figure 5-4.—Standard marking syst
Page 105 and 106:
DIAMOND WHEELS Diamond grinding whe
Page 107 and 108:
WHEEL CARE AND STORAGE It’s easy
Page 109 and 110:
allows cutting speeds approximately
Page 111 and 112:
Figure 5-13.—Surface finish vs no
Page 113 and 114:
Figure 5-17.—Boring bars for carb
Page 115 and 116:
Figure 5-19.—Chip breakers. a rad
Page 117 and 118:
Internal-threading tool: The intern
Page 119 and 120:
Downcutting tool: You may grind and
Page 121 and 122:
Figure 5-32.—Grinding drill lip c
Page 123:
Figure 5-37.—Grinding a twist dri
Page 126 and 127:
ways in alignment with the headstoc
Page 128 and 129:
Figure 6-4 shows this plate for the
Page 130 and 131:
Before you insert a center or tooli
Page 132 and 133:
FEED ROD The feed rod transmits pow
Page 134 and 135:
lower lever has eight positions, ea
Page 136 and 137:
Figure 6-14.—Quick-change toolpos
Page 138 and 139:
Figure 6-21.—Three-jaw universal
Page 140 and 141:
Figure 6-26.—Cutaway showing the
Page 142 and 143:
Figure 6-32.—Thread dial indicato
Page 144 and 145:
TRACING ATTACHMENTS A tracing attac
Page 146 and 147:
2. Place the level across the bed a
Page 148 and 149:
Figure 6-41.—Aligning lathe cente
Page 150 and 151:
Figure 6-45.—Boring center hole.
Page 152 and 153:
ends of the mandrel when you press
Page 154 and 155:
Figure 6-52.—Centering work with
Page 156 and 157:
Figure 6-56.—Work mounted on a ca
Page 158 and 159:
FEED is the amount the tool advance
Page 160 and 161:
Rough Turning Figure 6-62.—Rough
Page 162 and 163:
Square, round, and “V” grooves
Page 164 and 165:
Figure 6-69.—Knurled impressions.
Page 166 and 167:
machined surfaces that could become
Page 168 and 169:
produced by the same amount of seto
Page 170 and 171:
cross-feed screw and the cross-slid
Page 172 and 173:
When special threads are required b
Page 174 and 175:
Figure 6-83.—Acme thread and form
Page 176 and 177:
where An example of a pipe thread i
Page 178 and 179:
The wire size you should use to mea
Page 180 and 181:
Using the Thread-Cutting Stop Becau
Page 182 and 183:
Figure 6-96.—Finishing the end of
Page 184 and 185:
shown in figure 6-101. Two slots ar
Page 186 and 187:
Figure 7-1.—Universal milling mac
Page 188 and 189:
A. Spindle G. Spindle speed selecto
Page 190 and 191:
with a split clamp to the overarm a
Page 192 and 193:
to the table of the milling machine
Page 194 and 195:
that most index heads have a 40 to
Page 196 and 197:
Rapid indexing is used when a large
Page 198 and 199:
or one complete turn plus 36 holes
Page 200 and 201:
allows you to index divisions from
Page 202 and 203:
from the one in which the pin is in
Page 204 and 205:
Figure 7-24.—Side milling cutter.
Page 206 and 207:
A. B. C. D. E. Figure 7-32.—Doubl
Page 208 and 209:
Figure 7-36.—Inserted tooth face
Page 210 and 211:
Figure 7-43.—Sprocket wheel cutte
Page 212 and 213:
Figure 7-48.—Stub arbor. or on th
Page 214 and 215:
Figure 7-54.—Spring collet chuck
Page 216 and 217:
Figure 7-56.—Face milling. FACE M
Page 218 and 219:
11. 12. 13. 14. 15. 16. 17. 18. 19.
Page 220 and 221:
A. Lock screw for dog D. End mill B
Page 222 and 223:
8. 9. 10. 11. 12. 13. 14. 15. 16. 1
Page 224 and 225:
11. 12. 13. 14. 15. 16. 17. 18. 19.
Page 226 and 227:
Figure 7-71.—Visual alignment of
Page 228 and 229:
machine table. You will hold the cu
Page 230 and 231:
Figure 7-77.—Boring with a fly cu
Page 232 and 233:
Figure 7-79.—Vertical milling att
Page 234 and 235:
Table 7-2.—Surface Cutting Speeds
Page 236 and 237:
Table 7-4 shows recommended chip lo
Page 238 and 239:
Figure 8-2.—A 36-inch vertical tu
Page 240 and 241:
28.194 Figure 8-3.—Refacing a val
Page 242 and 243:
HORIZONTAL BORING MILL The horizont
Page 244 and 245:
7. After you have tightened the mou
Page 246 and 247:
The table can be power driven to pr
Page 249 and 250:
CHAPTER 9 SHAPERS, PLANERS, AND ENG
Page 251 and 252:
Figure 9-3.—Swiveled and tilted t
Page 253 and 254:
extent in planer and shaper work To
Page 255 and 256:
the cutting speeds and related mach
Page 257 and 258:
Figure 9-10.—Internal keyway: A.
Page 259 and 260:
7. 8. 9. 10. 11. 12. 13. 14. Replac
Page 261 and 262:
or housing attached on one side of
Page 263 and 264:
Figure 9-18.—Engraving machine. F
Page 265 and 266:
CUTTER SPEEDS The speeds listed in
Page 267 and 268:
can readily see it after grinding t
Page 269 and 270:
Figure 9-29.—Using an indexing at
Page 271:
Any further movement of the work wi
Page 274 and 275:
Figure 10-1.—Grain depth of cut;
Page 276 and 277:
To select the proper work speed, ta
Page 278 and 279:
Figure 10-8.—Magnetic chuck used
Page 280 and 281:
can do on a surface grinder. Use th
Page 282 and 283:
for straight cylindrical grinding o
Page 284 and 285:
Figure 10-15.—Typical tooth rest
Page 286 and 287:
of the work. Raise or lower the whe
Page 288 and 289:
Figure 10-23.—Staggered-tooth sid
Page 290 and 291:
Figure 10-28.—Grinding the periph
Page 292 and 293:
Once the teeth are uniform, they sh
Page 294 and 295:
After you have honed out the inaccu
Page 296 and 297:
MACHINES With the rapid development
Page 298 and 299:
Figure 11-3.—Slant bed for CNC la
Page 300 and 301:
Figure 11-6.—A typical CNC contro
Page 302 and 303:
Figure 11-8.—Continuous-path angl
Page 304 and 305:
CHAPTER 12 METAL BUILDUP CHAPTER LE
Page 306 and 307:
Figure 12-1.—Typical installation
Page 308 and 309:
Figure 12-5.—A typical sandblaste
Page 310 and 311:
Clean, dry air is essential for pro
Page 312 and 313:
It can reduce the amount of masking
Page 314 and 315:
quality assurance function of the p
Page 316 and 317:
pass-fail. In our educational syste
Page 318 and 319:
straighten a shaft, however, always
Page 320 and 321: Figure 13-4.—Lapping tools. has t
Page 322 and 323: pipe in which the valve is installe
Page 324 and 325: Figure 13-10.—Constant-pressure g
Page 326 and 327: When you install the control valve
Page 328 and 329: casing wearing rings, impeller wear
Page 330 and 331: Figure 13-17.—Removing a broken b
Page 332 and 333: Figure 13-23.—Metal disintegrator
Page 334 and 335: Figure 13-25.—Portable boring bar
Page 336 and 337: Figure 14-1.—Cutting specially sh
Page 338 and 339: For example, use the following proc
Page 340 and 341: at an angle to each other, as long
Page 342 and 343: Figure 14-6.—Development of evenl
Page 344 and 345: Table 14-1.—"K" Factor Table Tabl
Page 346 and 347: Figure 14-11.—Standard universal
Page 348 and 349: 6. Find the NPD. 7. Find the 8. Fin
Page 350 and 351: FA - Face angle OD - Outside diamet
Page 352 and 353: 7. Pitch diameter (PD)—This is th
Page 354 and 355: SELECTING A BEVEL GEAR CUTTER To cu
Page 356 and 357: Figure 14-20.—Profiling a bevel g
Page 358 and 359: . Use the following formulas to sol
Page 360 and 361: Figure 14-25.—Milling machine set
Page 362 and 363: 9. Diametral pitch (DP) METHOD OF M
Page 364 and 365: explains the classes and the manufa
Page 366 and 367: GRAINS (irregularly shaped crystals
Page 368 and 369: Figure 15-2.—Microscopic structur
Page 372 and 373: Figure 15-8.—Grid for heat-treati
Page 374 and 375: Table 15-3.—Average Cooling Rates
Page 376 and 377: cases. A wide variety of quenching
Page 378 and 379: These various temperature arrests o
Page 380 and 381: known as pearlite, and the A1 tempe
Page 382 and 383: quickly cooled to and held at a som
Page 384 and 385: Available information indicates tha
Page 386 and 387: slowly from the tempering temperatu
Page 388 and 389: Table 15-4.—Heat-Treating Tempera
Page 390 and 391: Figure 15-20.—Design of a cam. A.
Page 392 and 393: In carburized steel, spalling is ca
Page 394 and 395: used to make positive identificatio
Page 396 and 397: HONING—Finishing machine operatio
Page 398 and 399: Table AII-2.—Decimal Equivalents
Page 400 and 401: Table AII-4.—Formulas for Dimensi
Page 402 and 403: Table AII-5.—Number, Letter and F
Page 404 and 405: Table AII-7.—Screw Thread and Tap
Page 406 and 407: Table AII-9.—3-Wire Method of Mea
Page 408 and 409: Table AII-11.—Circles Circumferen
Page 410 and 411: Table AII-13.—Taper Per Foot and
Page 412 and 413: p 1 I vi 2 P F \ = = a AII-16
Page 414 and 415: Table AII-16.—Drill Sizes for Tap
Page 416 and 417: Having Circular pitch Circular pitc
Page 419 and 420: APPENDIX IV DERIVATION OF FORMULAS
Page 421:
(1) NT is the connecting link betwe
Page 424 and 425:
Walker, John R., Machining Fundamen
Page 427 and 428:
A Adjustable gauges, 1-7 adjustable
Page 429 and 430:
Engine lathes, 6-1 attachments and
Page 431 and 432:
Layout methods, 2-8 M forming angul
Page 433 and 434:
Stub tooth gears, 14-27 American st
show all

Machinery Repairman

Create successful ePaper yourself

Delete template?

Save as template?