MetalworkingFun Forum
Todays Project - What did you do today? - Printable Version

+- MetalworkingFun Forum (http://www.metalworkingfun.com)
+-- Forum: Machining (http://www.metalworkingfun.com/forum-5.html)
+--- Forum: Projects (http://www.metalworkingfun.com/forum-7.html)
+--- Thread: Todays Project - What did you do today? (/thread-727.html)

Pages: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552

RE: Todays Project - What did you do today? - stevec - 02-16-2014

(02-15-2014, 08:54 PM)PixMan Wrote: It seems the cutting pressure with a .010" deep (per side) pass was a bit too much and it started slipping in the chuck. Because it was following the previous passes, the tool never left it's path so no damage there.

I'm having a little trouble understanding that the workpiece slipped in the chuck but the "tool never left it's path". 17428

Good job on the snowblower repair/improvement. Thumbsup

RE: Todays Project - What did you do today? - PixMan - 02-16-2014

What I mean it that the threading insert seemed to stay within the path of the three previous passes.

If a part you're threading slips in a chuck that's driving it, the most common failure would be that the workpiece stops and the carbide shatters. In this case it sounded like a tiny bit of chatter, and in the next instant I noticed the end of the work had come away from the live center. That's when I retracted the tool and stopped the process. All I can assume is that there were very tiny, unnoticeable stops to the workpiece that for some reason didn't catch and didn't chip the carbide insert.

RE: Todays Project - What did you do today? - stevec - 02-16-2014

OK Ken, I was wondering, when the piece slipped in the chuck the still advancing tool pushed the workpiece further into the chuck.
That makes sense and good luck for you.
All's well that ends well.

RE: Todays Project - What did you do today? - PixMan - 02-16-2014

This sets me back a week on the project. I'm going to cut another piece of stock, neck down a 3/8" to 1/2" section behind where the thread goes (the Ø20mm section) and mill flats on the last 1-1/2" to clamp in the chuck. I'll do four flats at 90º apart and for the first time, mount my 12" 4-jaw independent chuck so I can be sure that end is true. Now firmly clamped, I need to upgrade the threading tool.

I looked at what I'd threaded and saw a problem. It was clearly pushing and though chip control was perfect it wasn't cutting right. Checking the helix angle, a 1-1/4-5ACME has nearly 3º of lead angle. The standard lay-down holder accounts for 1 to 2 degrees of lead angle, so I need to get a YE4-2P or YE4-3P anvil for the holder. Since it's a borrowed holder, I'm just going to buy my own and get the additional anvil with it. That should make threading this MUCH easier, and make a high quality thread form.

RE: Todays Project - What did you do today? - Old Iron - 02-16-2014

I know this should be in gun smithing forum but it was my project for today
Its only a AR15 lower this is the forth one I've did.

Paul

RE: Todays Project - What did you do today? - PixMan - 02-16-2014

Was that made from a solid block, or a casting you buy and have to finish? Either way, looks good and I know they're a lot of work and a few special tools are required. Doesn't take but a moment of inattention to make it junk!

RE: Todays Project - What did you do today? - Old Iron - 02-16-2014

It was a forged 80% receiver, I do have a solid one and I'm in the process of making the plates to hold it in the vise.

Yea it only takes one oops and its junk, Been there done that and I learned not to have anyone around while your doing them.

Even at 55.00 it is expensive mistake. I've build one in 5.56 and one in 7.62X39 this one will be a pistol in 7.62X39.

Paul

RE: Todays Project - What did you do today? - PixMan - 02-23-2014

Neil came over today with a little "rush job". As I didn't get the threading tool I'd ordered to work on Darren's parts because UPS reported a "train failure" coming from Michigan to Massachusetts, I was going to work on Neil's remaining parts. He showed up with a cast aluminum motorcycle wheel that he was trying to upgrade to a right angle Schraeder valve.

The hole in the wheel was just a little too large for the o-ring to seal, so we thought to bore (and counterbore) the existing hole to press in a step-down bushing. As necessity is the mother of invention, we fashioned a way to clamp it to the side of my Alliant milling machine. I quickly made a large aluminum "washer" to cover the bearing while allowing a 3/8" stud to pass through the 14mm bore. Luckily I have a bag full of 3/8-16 threaded T-nuts and found one that fit the slot normally used for the table stops. It worked a treat!

[Image: IMG_2173-r_zps36a3327b.jpg][Image: IMG_2174-r_zps0f029950.jpg]

I wish I'd thought to lake more photos. We first made the stepped bushing far too long, it would have stood proud of the mounting surface on the inside of the wheel. So then I quickly made a split aluminum bushing to hold the stepped press-in bushing in the lathe, reaching over the larger shoulder O.D. to clamp on the smaller "press fit" diameter. Of course Murphy was in the shop haunting us all day, so we miscalculated something and somehow cut it a millimeter too short.

Of course we didn't know it would be too short until after we'd pressed the bushing into the wheel with a permanent Loctite product. (I had also made a quick, stepped press tool to insert the bushing.)

No way to press it back out from inside the wheel anyhow, so we straightened out the milling machine and deftly milled the boss where the Schraeder valve mounts. The new smooth-milled surface will give a better sealing surface for the o-ring on the valve anyhow.

It all took about 4 hours from start to finish, but it's PERFECT....as long as it holds air. I'll ask Neil (expat) to get a finished photo of the work.

RE: Todays Project - What did you do today? - Mayhem - 02-23-2014

Nice work Ken. Ingenious set up too.

RE: Todays Project - What did you do today? - Hawkeye - 02-23-2014

I had noticed that my big drill press wasn't giving me vertical holes, so today was the day to try to true it up. The table had been finished with a pass from a very large flycutter or face mill - something around 16" diameter judging from the tool marks. Checking with a square showed that the table needed to 'nod' to true up front to rear.

Since I now have a lathe that's big enough (the table is almost 14" diagonally), I decided to face the table. Because of the large diameter, I needed to use carbide at the slowest lathe speed to get an acceptable cutting speed for the cast iron table. The brazed carbide cutter has a 1" shank and is very solid - necessary due to the interrupted cuts.
[attachment=7800]

You can see the original tool marks, especially on the rim at the top.
[attachment=7801]

As shown, the centre hole was a bit off centre. A touch-up with a boring bar made short work of that.
[attachment=7802]

Shimming with aluminum foil at the top of the table support arm gave enough nod to level the table. A much nicer finish than the original.
[attachment=7803]