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Our quoting guy may have made a whoopsie. Quoted parts comig out of a chunk of material 32" diameter, and 14" thick. The print said the material is TZM, which he didn't look up and assumed it was some weird steel alloy. Nope, it's almost pure cast molybdenum and it weighs like 3800 pounds and it's sitting on our shop floor and it's twice as much than the max weight on our biggest wire machine, so I don't think the customer is going to be pleased.
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Feb 1, 2019 04:28
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Put some wood under it you'll be fine
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Feb 1, 2019 04:32
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fps_bill posted:3. Chuck forstner bit in the lathe, make a couple light passes. Measure, about 60 has to come off so I'll dial in 30 planning to check again, sneaking up on final dimension. Measure after that pass and I'm loving 10 thou under. Fml! Oh well, grab the parting tool and make the shoulder square. Ahhh direct vs indirect dial. Diameter vs radius. Pretty easy way to fuckup because it's a tossup what any give lathe will have. Some lathes use a mix of dials so, yeah, gotta pay attention.
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Feb 1, 2019 06:00
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I watched a lot of videos on using lathes and such and most of them to me seemed to talk only about radius. So I assumed all lathes measured the radius and I got used to thinking about that before ever owning my own lathe. It was therefore some annoying occasions before I figured out my lathe cross slide indicates diameter. I still think it feels more natural to think in radius than diameter though, just because that's how I started out thinking about it. Doing anything precision-y I use a dial indicator against the cross slide.
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Feb 1, 2019 07:28
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Wait until you ram the tool deep into the part on a machine that turns out to have the handwheels graduated in hundredths of an inch instead of thousandths 
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Feb 1, 2019 07:42
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Sagebrush posted:Wait until you ram the tool deep into the part on a machine that turns out to have the handwheels graduated in hundredths of an inch instead of thousandths Thats a thing? On normal sized lathes or on the massive fuckers you see turning crankshafts for ships and poo poo thats like 10' in diameter?
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Feb 1, 2019 08:00
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Normal sized machines, but cheap ones. A lot of little benchtop machines have the cross-slide graduated in .01s, for instance, because the expectation is that you'll use the compound rest for precision movements. It doesn't hurt to stick a dial indicator on the carriage/apron/whatever any time you're getting familiar with a new machine, just to double-check that everything does what you're expecting. As a bonus, doing so also handles backlash compensation, and it'll save your rear end when you realize that some dummy broke the set-screw on the handwheel scale and it's been slipping the whole time you've been making that cut 
Sagebrush fucked around with this message at 09:45 on Feb 1, 2019 |
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Feb 1, 2019 09:41
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His Divine Shadow posted:I watched a lot of videos on using lathes and such and most of them to me seemed to talk only about radius. So I assumed all lathes measured the radius and I got used to thinking about that before ever owning my own lathe. It was therefore some annoying occasions before I figured out my lathe cross slide indicates diameter. It's diameter in CNC and that's how I learned, so making adjustments radially would be weird to me.
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Feb 1, 2019 09:42
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Yea thinking of material per side to remove is what I'm used to, it through me off that our little manual lathe was direct or whatever it is.
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Feb 1, 2019 11:37
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This doesn't directly have anything to do with metalworking, but I think it has really big repercussions down the line for machining/CNC operating/a whole swathe of careers really. i kinda flailed at sth along these lines in this thread/the hobby CNC thread ages ago and didn't know what I was talking about and shut up pretty quick, but here's something much more concrete and less popsci-ey (also ignore the title entirely, it's horrible, and the authors are about 5000% more self-important about their work than is warranted so ignore all the stuff about machine self-awareness, its the implications of the actual research and not the researcher reckons that are interesting) https://engineering.columbia.edu/press-releases/lipson-self-aware-machines https://www.youtube.com/watch?v=4dp_iiESLo8 quote:For the study, Lipson and his PhD student Robert Kwiatkowski used a four-degree-of-freedom articulated robotic arm. Initially, the robot moved randomly and collected approximately one thousand trajectories, each comprising one hundred points. The robot then used deep learning, a modern machine learning technique, to create a self-model. The first self-models were quite inaccurate, and the robot did not know what it was, or how its joints were connected. But after less than 35 hours of training, the self-model became consistent with the physical robot to within about four centimeters. The self-model performed a pick-and-place task in a closed loop system that enabled the robot to recalibrate its original position between each step along the trajectory based entirely on the internal self-model. With the closed loop control, the robot was able to grasp objects at specific locations on the ground and deposit them into a receptacle with 100 percent success. the paper authors get lost in speculating about MACHINE SELF AWARENESS but the potential applications of this to, say, a CNC machining centre are pretty clear. you've got a clear and well-defined task range, straightforward criteria for success, failure and places in between, and usually a constant stream of fairly-similar programs being run for a data-set to learn from. you can spitball all day, but it seems like you can break most of CNC operating down into the sorts of straightforward and empirical discrete tasks that machine deep learning is adept at elsewhere, stuff like idk: anticipating the conditions for ideal machining given real observed conditions and results and which parts get accepted vs rejected, predicting common operator errors along the lines of "it crashes the probe whenever the dude sets z-height as 10. instead of 1.0", figuring out where fixtures are without the operator giving it that information, actively compensating for subtle machine conditions even most skilled operators miss like, i dunno, slop from part wear increasing over months and years or anticipating how out of true a vise will be based on the forces involved in the crash that just happened, etc etc. some deliberate software compensation already exists in various forms- a spindle resonance vibration compensation routine was an example pointed out to me before- but the machine working that out all on its own doesn't seem like science fiction any more, and that's got Several Ramifications for skilled machine operating of any sort as a career
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Feb 2, 2019 03:17
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Ambrose Burnside posted:been poring through human-powered machine tools again, here's the highlights That is fascinating. Thanks for posting. drat, now I want one of each.
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Feb 2, 2019 07:05
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its a travesty that treadle/pedal/etc drives for tools take up an enormous amount of room and are machine-specific because man oh man if you're not in a rush they're just so dang intuitive and pleasant to use. maximum tactile feedback and effortless soft-touch delicate operations for d a y s
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Feb 3, 2019 19:22
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I'd kill for a treadle grinder for my blacksmithing. Sadly they're $fuckoff when I can find one at all
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Feb 3, 2019 21:22
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Like a bigass old-fashioned stone grinding wheel? yeah they're v hard to find in good condition because nobodys exactly making those wheels any more. and then a large fraction of whats left still ends up dumped in someone's flowerbed as home decor, doomed to be ruined and split from frost heave within a couple years, similar to all those great old anvils turning to rust as a thoroughly-wasted front yard folksy-cred prop. you could design something using a hand-crank or treadle drive that's built around modern abrasives w comparative ease, tho- treadle-crank linkage directly turns a bicycle wheel or built-up plywood wheel to get some flywheel smoothing action, belt/pulleys link the flywheel to the grinder spindle. crude belt-driven tools are great because you really can just kind of slap em together from garbage, sufficiently sturdy + rigid garbage anyways i have fever dreams of converting a sewing machine-less Singer treadle base (which you run into sometimes as garbage/scrap iron valued if the machine's missing) into a Treadle Workstation- work out two or three small, easily-moved machine tools and adapt/build them to interface with the base and pulley drive arrangement and swap them out as needed. My easily-converted-yet-useful tool picks would be 1) a Taig micro metalworking lathe, 2) a light grinder (prolly a bit like the one I posted) that can mount stone wheels or lightweight arbors for cheap adhesive-backed paper abrasives, and 3) as long as it's a fever dream, one of those old-school miniature camelback drill presses already configured for belt drive  
Ambrose Burnside fucked around with this message at 23:21 on Feb 3, 2019 |
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Feb 3, 2019 23:15
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The first part of this video he does something similar. https://www.youtube.com/watch?v=8U7ED6k5NLg
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Feb 4, 2019 01:25
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I don't miss my old job and the insane stress that came with it but I miss having access to a lathe, drill press, mig and tig and bulk scrap 316 stainless 
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Feb 4, 2019 02:23
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This is the real dream machine right here https://www.youtube.com/watch?v=cDeoCNRuKOk&t=3s A bicycle powered grinder that uses double sided tape and emery cloth as an abrasive. Still requires a big heavy bit in the middle, but is awesome as hell.
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Feb 4, 2019 04:40
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Bit hard for me to find the attraction to the treadle powered stuff. Those big sandstone wheels are common here and I got one, it's meant to be run in a water through and in the olden days it was usually wife powered instead of treadle, but ever since ww2 lots of people refitted their setups with motors. And that's what I got at home, definitely wouldn't want it without a motor. It's the precursor to tormeks. Gets stuff real sharp though, I think the wheel is equivalent to 600 - 1000 grits.
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Feb 4, 2019 06:01
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I _might_ get first refusal on a 3ph milling machine. What sort of money would it be to use it on single phase? Is it even possible? It’s a 2.2KW 3HP motor according to its plate. I don’t need it at all but they just want rid of it and I happen to know it’s _never_ been used since it was bought 8-10 years ago.
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Feb 6, 2019 19:36
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Rapulum_Dei posted:I _might_ get first refusal on a 3ph milling machine. What power do you have available? 110V? 220V? You can use a de-rated VFD to convert single phase to 3 phase. Won't work so well if you only have 110V. Rotary phase converters are a thing but I've only done VFD's so can't comment on it.
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Feb 6, 2019 20:31
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In TYOOL 2019 use a vfd. I have a bridgeport with a homebrew rotary converter that was done that way because of free parts - and am converting it over. Vfds are in the couple hundred bucks range.
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Feb 6, 2019 21:10
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Yooper posted:What power do you have available? 110V? 220V? 240V
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Feb 6, 2019 21:17
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Rapulum_Dei posted:I _might_ get first refusal on a 3ph milling machine. Is it actually a 3 phase motor? I don't know if its actually common but I've had a handful of machinists call 1 phase 3 wire setups as 3 phase.
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Feb 6, 2019 21:57
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Rapulum_Dei posted:240V OK, you've got a few options. Depending on budget you can go with an AliExpress or BangGood VFD. I've got one on a low usage spindle and it's fine, but I've only got a few dozen hours on it. Next on the list is the AutomationDirect GS2. We run these and they are decent but the life isn't what I like for high duty cycle applications. We recently pulled one out that tripped randomly at the upper end-lower end of the range. No idea why. My recommendation is for an ABB ACS150. ACS150-01U-09A8-2 I've run a shitload of different VFD's and now that I've switched to ABB my usage has gone down to virtually zero. We have one on a high load high RPM application grinder that runs two shifts and I haven't had to replace the drive in 7 years. Comedy side effect - The GS2 and Ali VFD will both spew out AM radio destroying interference.
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Feb 6, 2019 22:05
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Rapulum_Dei posted:I _might_ get first refusal on a 3ph milling machine. If you're in Australia it'd run on single phase, 2.2kW would be pushing it on a single plug although theoretically they can handle 240v 10a, even if you could get a 15A circuit put in or converted for it you'd be safe. It would depend on the startup current draw Source: I work with pumps and vfd's
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Feb 6, 2019 22:43
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Cheers Yooper, that gives me an idea of what to budget for, plus i’ll need to think about tooling IF it works out. I’m only assuming it’s a 3 phase motor because it’s currently connected to a 3 phase supply in the workshop it’s in. AFAIK it was bought and installed but never had any tooling so never turned a wheel since. And now no-one knows how to use it, it’s taking up a lot of space and the boss just wants it to _go away_ Here’s a similar one https://www.machinery-locator.com/for-sale/76186/EXCEL-PKTM380VA-Turret-Mill-2006 I can get it forklifted into a twin axle trailer without too much trouble. How I get a approx 1200kg OFF agin at the other end might be interesting but I’m willing to give it a shot  Where it’s going has 240v and a 16amp circuit I put in for welding. Rapulum_Dei fucked around with this message at 23:12 on Feb 6, 2019 |
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Feb 6, 2019 22:48
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His Divine Shadow posted:Bit hard for me to find the attraction to the treadle powered stuff. Those big sandstone wheels are common here and I got one, it's meant to be run in a water through and in the olden days it was usually wife powered instead of treadle, but ever since ww2 lots of people refitted their setups with motors. And that's what I got at home, definitely wouldn't want it without a motor. It's the precursor to tormeks. Gets stuff real sharp though, I think the wheel is equivalent to 600 - 1000 grits. For real work, where time is money, you'd never use human power unless you had no other choice or there were extreme extenuating circumstances like unreliable electrical service where you're workin or w/e, you're right. for personal projects or other similar things where just making something is done in a pleasant way for its own sake, where your priorities are different, the dynamic of those sorts of tools stops being one of use limitations and inconvenience and becomes one of a much "closer" tactile, touchy-feeley relationship to the work and the process. It's a tremendous appeal of hobby blacksmithing/silversmithing etc that's largely absent from modern production- and throughput-oriented machining tools and practices. Smiths do this same thing all the time, but it's clearer because the default is that human-powered work- you use the power hammer for making money because you're not an idiot and want rotator cuffs that aren't 100% grinding bone fragments by age 35, but you pick up a hammer and use that personal touch for gifts and delicate tasks and jobs that aren't just paycheques. I think of it like modern sailing ships- they've been overwhelmingly commercially-obsolete since before living memory, and in strictly technical terms are vastly inferior to anything motorized, but they're still very popular recreational vessels for not only rich doctor retirees but also professional /merchant mariners who actually find satisfaction in making the task of sailing, from that strictly-technical perspective, much more inconvenient, limiting, and personally-demanding. Ambrose Burnside fucked around with this message at 23:52 on Feb 6, 2019 |
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Feb 6, 2019 23:49
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Ambrose Burnside posted:I think of it like modern sailing ships- they've been overwhelmingly commercially-obsolete since before living memory, and in strictly technical terms are vastly inferior to anything motorized, but they're still very popular recreational vessels for not only rich doctor retirees but also professional /merchant mariners who actually find satisfaction in making the task of sailing, from that strictly-technical perspective, much more inconvenient, limiting, and personally-demanding. Very few people can afford the diesel (much less a vessel with large enough fuel tanks) to cross oceans or go around the world; many many people do this per year on sailboats.
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Feb 6, 2019 23:53
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Rapulum_Dei posted:Cheers Yooper, that gives me an idea of what to budget for, plus i’ll need to think about tooling IF it works out. We have an almost exact clone of that machine, except it's yellow. It's a solid little machine, the speed control is a bit lovely as is the integrated motor. Beyond that its been a really great machine.
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Feb 7, 2019 00:51
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Rapulum_Dei posted:I _might_ get first refusal on a 3ph milling machine. You run 240 single phase to the 3ph motor, use the smaller motor to get the big one turning and up to speed (you can actually wrap a cord around the shaft and start it like a lawnmower!) and once it is spinning the right way, turn power on to the converter motor. The three phase running on two phase motor acts as a generator, and you tap off it to run the third leg/phase back to your panel, which you connect the mill to. I'm fuzzy on the exact details of how everything gets wired(because I'm not an electrician) but it works, and can be done cheaply. I used to work in a shop full of old woodworking machines and the whole shop ran on this system for 40 years. He'd gotten the plans for it from an old machinist. I'm not sure sure if it's steady enough power to run real delicate CNC kind of stuff on, but it will make the motor spin and with no loss of power like an inverter. Is there a loss of power with VFDs like with older inverters?
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Feb 7, 2019 01:17
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Kenshin posted:Uh don't forget the fuel cost & storage factor. yeah it's def not a perfect analogy, i'm on the great lakes so i'm more used to/thinking of daytime trippers where vessels tend to be smaller, you're often not *going anywhere* that isn't a fishing spot, cool nearby island, quayside bar etc, and fuel cost/bunkerage isnt the hard limiting factor on what you can do, in the way it can be w long-distance oceanic travel fuel costs were also what i had in mind irt the last factor keeping some working sailing ships viable in north america until relatively recently- before factory ships industrialized the atlantic canada fisheries the majority of boats were family-owned and operated, often being handed down from father to son, and the addition of motors didn't kill sail use or the needed skillsets, they just freed fisherman from being shackled to favourable winds. sails were still great for conserving fuel and actually got leaned on harder and harder to pinch pennies as those small time operations got increasingly difficult to operate profitably ...my broader point stands tho  back to your scheduled metalworking post content
Ambrose Burnside fucked around with this message at 02:36 on Feb 7, 2019 |
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Feb 7, 2019 01:54
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Kaiser Schnitzel posted:Is there a loss of power with VFDs like with older inverters? It depends. Most units that say they are rated for 1ph usage don't derate. That said I've seen 1ph with a shiny little asterisk that say you should derate. I think a servo drive would throw a conniption fit if you tried to run it on a phase converter 3 phase.
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Feb 7, 2019 01:55
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Rapulum_Dei posted:Cheers Yooper, that gives me an idea of what to budget for, plus i’ll need to think about tooling IF it works out. 3800 watts should be okay but maybe have an electrician confirm it will work, it might draw 20A on start
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Feb 7, 2019 02:58
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Finished up the last blacksmith class last night. Spent the class finishing up our blacksmith knives, grinding, heat treating etc... Lessons learned, drawing out the handle was a huge PIA but I'm happy with it for my first knife. I've got the bug and want to hammer more metal things. 
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Feb 7, 2019 16:27
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I like it! That’s a novel, effective and artistic design.
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Feb 7, 2019 23:38
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I was gonna do some baking so naturally the first step is the lathe. I want to make Runeberg Tortes, a traditional finnish cake: They are made using cylindrical forms without bottoms 2" wide and 2-3/8" tall.  Can also be aluminum  So instead of buying them, in my madness I cut up a suitable steel pipe and meant to turn them all to size and pretty them up... but alas, they are too weak to be turned, can't grip them hard enough in the chuck without destroying them and they get loose. How does one best solve this? The only way I see is I turn a piece of steel or aluminum that's a really really tight fit and put that inside to support the pipe so I can chuck it up hard and good. Any other ideas?
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Feb 8, 2019 08:15
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This probably isn't helpful but I'd start by turning the length of pipe, uncut, and cutting each form as I went- the full length of tubing will resist buckling and deformation with many times the strength of each individual section. I've successfully worked tubing on the lathe before this way with no issues. With any project where workholding of final parts is a challenge, like here, do everything you can to part the work off the stock as late as you can, it simplifies everything dramatically. My first pick, if the stock wasn't expensive, is starting over and working with the entire pipe chucked up in the lathe- the remedy will likely take longer than starting over will. Assuming you wanna make the cut stock work, you need to either 1) distribute the clamping force more equitably across as much surface area of the tube as is possible; or 2) Supporting the stock from the inside so conventional three-jaw clamping won't deform it, like you suggested. For 2), you may find that just clamping the pipe with the outside edges of the chuck jaws may be enough, it's part of the reason they're usually radiused. You can also turn a plug mandrel like you're thinking, but I wouldn't make a solid metal one- for it to really support the pipe with that close a fit, just getting it in and out of the tube will be a struggle and you may damage the pipe. Undersize it and it may slip out during machining and take a trip across the shop. A tapered metal mandrel is viable but the taper angle needed is very slight and ime hard to do to the proper spec without a taper attachment, and it would also almost certainly flare out the soft thin tubing somewhat. A wood plug (which deflects easily and can get the needed fit-up) is acceptable if you can mechanically-secure it in the pipe, i.e. with two flanged sections on either end with a through-hole to allow fastening them together with nut and bolt. The best internal support is going to be an expanding mandrel, though. They're a fair bit of work to make but it's not difficult work and they function very well, you may be interested in designing one because they're invaluable workholding tools for anything that benefits from very even and well-distributed internal cylindrical support. For 1), if you have or are inclined to make aluminum jaws for the chuck you can also turn those to have a radius matching that of the tube OD. Another nice feature of this approach is that the bottom of the radius cut (it wont be across the full jaw depth) acts as a depth stop, which means if you're thoughtful about how you cut the jaws you can use it to index each part for repeatable operations. You can also probably achieve 1) by making an external split mandrel of sorts. find a thick-walled pipe size that the working stock telescopes neatly into, cut a section a little longer than the lathe jaws are, and then split that section lengthwise almost all the way to the bottom, leaving a thin ring of material joining the two (drilling holes at the cut roots will provide relief). Place this sleeve over the stock in the chuck, with the solid ring inside the spindle beyond the clamping jaws, and it'll distribute the jaw force much more evenly across the surface of the pipe instead of at three small pressure points. e: oh yeah if you make a plug mandrel another way to do it safely w/o a screw-together design is two halves, both flanged, one chucked up and the other supported by the live centre Ambrose Burnside fucked around with this message at 18:30 on Feb 8, 2019 |
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Feb 8, 2019 18:13
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wildcard alternatives for tubing support: eutectic low-melting alloys, tin, a cast-in-place slug of hard urethane rubber pushed out of hte first tube and reused for the rest, hard chaser's pitch. lead is also fantastic for this but it's rather out of vogue nowadays for some, some reason, i cant quite remember why, also why are my extremities always numb
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Feb 8, 2019 18:23
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There was a guy on here a year or two ago who was making musical instruments, he had all kinds of jigs and setups for stretching and forming tube. None of them, IIRC, were lathes.
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Feb 8, 2019 18:40
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Leperflesh posted:There was a guy on here a year or two ago who was making musical instruments, he had all kinds of jigs and setups for stretching and forming tube. None of them, IIRC, were lathes. Yeah, the trumpet guy. He had some really cool stuff but it was a lot of rolling and forming tools/jigs from what I remember.
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Feb 8, 2019 18:49
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