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oxbrain posted:I can't say what I'm working on except that it's aerospace R&D. Most of the time I'm running either a Mori Seiki NL1500 or a Toyoda FA800. We consider dimensional tolerances over +/-.005"(+/- 127 microns) to be gravy work. +/-.0005" (12.7 micron) tolerances are tight, but easy enough as long as you pay attention. The tightest I've ever worked with was +.0000"/-.0002", which is a 5 micron range. Same kind of tolerances in a mold making shop. During high school though, I worked for a couple weeks in an armored car fabrication shop. All the tolerances were like, +/- .010" (+/- 254 microns) poo poo was gravy. I used a vernier and a scale at that job. Occasionally (because I was in high school) I would just eye-ball a part and QC (my supervisor) would say it was good. Working in mold making, most of the mold frame is either +/- .005" or +/- .0005 for set cavities. The mold sets were very commonly +.0000"/-.0002". But we would take it all off the back of the sets and shim if we went too far, or put weld on and grind that down. We did that a lot.
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Mar 16, 2012 13:49
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oxbrain posted:We have to make everything to print, but sometimes we get it changed after explaining that it'll take another couple days if they really want that tolerance.  I have never met a machinist on salary.
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Mar 16, 2012 20:05
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Lord Gaga posted:
poo poo, I don't even wanna do overtime when I graduate machine school. We'll see how much luck I have with that dream! At least overtime on hourly means fat checks, even if I can only put up with it for a year or two.
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Mar 16, 2012 22:11
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Yeah salary gets real sweet when you start working 12-16 hour shifts. The harder you work the less you get paid 
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Mar 17, 2012 03:47
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Linux Assassin posted:Since were talking tolerances- for those that are doing this professionally what are some real world tolerances you've encountered, on what projects, and how does this affect how your build? Most common tolerance I've worked with in a weld shop was .015". So like a 64th of an inch. We were doing stainless steel surgical and medical equipment. We also made stretchers out of mild steel, and the tolerances were 3/32" on the frame.
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Mar 17, 2012 05:46
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In my experience 85+% of welders couldn't give a gently caress what tolerance you put on anything if its less than a 1/16th. If something needs to be precise I always machine it after welding and try to leave some for making stuff flat and perpendicular.
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Mar 17, 2012 19:55
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I just had to dig out this old print from when I was in school. When they handed us this thing I sat down at the layout table and just stared at it thinking "Oh dear christ." At least they bothered with a datum edge for the Y axis, but ugh. I ended up sitting there redrawing the thing with a sane layout. But since everyone else was sitting there with the same boggled expression I spoke up and said "What idiot drew this? This is terrible!" My scanner cut off the bottom edge of the info block, but it has "Drawing: DKP" A few people looked up and stared at me like I said something horrible before someone told me "Uh, DKP is Debbie Pitzer, the department head." She was standing right behind me.
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Mar 17, 2012 20:27
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Lord Gaga posted:In my experience 85+% of welders couldn't give a gently caress what tolerance you put on anything if its less than a 1/16th. If something needs to be precise I always machine it after welding and try to leave some for making stuff flat and perpendicular. I can confirm this is generally true, except that your percentage might be a little low.
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Mar 17, 2012 20:55
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Enos Shenk posted:I just had to dig out this old print from when I was in school. Please tell me that was on 8 1/2" X 11". If she wasted A1 for that, well it's time to take ol' yeller out back. Also, what the gently caress, everything is fractional and that's a die block? Jesus Christ almighty... 
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Mar 18, 2012 01:12
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Pro-tip: when you have to employ 23/32 as a fraction, just use decimals. Also, TOOLS TOOLS TOOLS TOOLS    My new anvil, just a lil feller. 66 pound Austrian-pattern with cathedral windows. He's real purdy, although I still have to grind the horn/windows smooth. Honestly, though, I'm more psyched about the old stuff I got.  Look at this leg vise. Loooooook at iiiiiiiiit. It's gorgeous.   This bell finial thing is half of the screw mechanism and it's kind of blowing my mind in regards to how gorgeous it is. I keep thinking, this is a tool that people were expected to beat on with hammers all day, and getting kind of vaguely sad at the state of tools nowadays.  Stake anvil, about half the weight of the Austrian. It's entirely round, no flat worksurface or nuthin. It honestly rings like crystal when I hit it with a hammer, I can't wait to work with it.  Tongs. Just cheap ol' beaters that i'll fix up. You can see the forge-welds where he joined the grippy bits to the handles, complete with cold shuts.
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Mar 18, 2012 03:00
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Random Number posted:Please tell me that was on 8 1/2" X 11". If she wasted A1 for that, well it's time to take ol' yeller out back. What's so hosed about this print? I don't get it.
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Mar 18, 2012 04:05
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SmokeyXIII posted:What's so hosed about this print? I don't get it. It's more than halfway to unreadable? There's way too many dimension lines. It's practically begging for ordinate dimensioning. Obviously, it's deliberately obtuse for testing purposes, but still, there's for the sake of learning, and there's for the sake of a professor showing off. And as Enos pointed out, the X-axis dimensions are just horrific. It's like spaghetti code. You can't know where topmost hole goes without first knowing where another hole is, which you can't place without finding the centerline, which isn't very clearly marked anyway, so you have to read the whole print just to figure out that that line marks the center, etc. Ambrose Burnside posted:Pro-tip: when you have to employ 23/32 as a fraction, just use decimals. Indeed, note that .72 is much more readable. (And within tolerances, I think. That part of the title block is hard to read.)
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Mar 18, 2012 04:30
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SmokeyXIII posted:What's so hosed about this print? I don't get it. Also, happy saint patty's day.
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Mar 18, 2012 04:35
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Lol I mean it's not a very nice print at all and it gave me a headache for sure figuring it out but I think a guy could build it off that print, with an advil. Right? I don't machine at all so I don't know much about tolerances however so maybe im way wrong. Happy saint pattys to you as well! I'm drinking my Guinness right now!
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Mar 18, 2012 04:59
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Ambrose Burnside posted:drat man, those have been welded twice, that's kind odd. Nice haul, that vise is amazing. How wide are the jaws?
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Mar 18, 2012 05:05
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4 1/2". I don't know how that stacks up but they're about as wide as my current mechanic's vice which is already getting wobbly and weird due to all my hammering on it. The jaws don't close together quite perfectly- they meet right in the middle and bow out by about half a milimetre by the jaw edges?- but I'm not too worried. Also the screw looks... hand-cut? I'm not sure how big screws like that were cut a century ago but there's an irregularity to it that's kind of throwing me off- regardless it still works perfectly, the closing/opening action is smooth as hell so everything's worked in properly. And yeah, double-welded tong handles. I don't know what the gently caress either. the other side isn't welded so roughly, you can't see the joins on the other face so I'm assuming they're good solid welds regardless. e: The vise has some identifying marking/stamps that you can kind of see in the last close-up of the bell fitting thing, but they're so faded as to be allllllmost illegible. I wanna do a pencil rubbing of 'em and try to figure out how old it is and where it came from. The stake anvil is actually French, who knows how it got to a Virginia antique store. Ambrose Burnside fucked around with this message at 06:14 on Mar 18, 2012 |
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Mar 18, 2012 06:12
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SmokeyXIII posted:Lol I mean it's not a very nice print at all and it gave me a headache for sure figuring it out but I think a guy could build it off that print, with an advil. Right? I don't machine at all so I don't know much about tolerances however so maybe im way wrong. It's buildable, but everything is +/- .0315" except for a couple written in dimensions, which are in black instead of red  It won't mate with the rest of the assembly due to tolerance issues is my guess though. I hate when you build a part without the assembly. You need to know what it mates with in-case you gently caress up, and so you know where you can leave stock for grind, and what should be left machine finished.
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Mar 18, 2012 14:29
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I just went rooting around my garage trying to find the finished part. Unfortunately I seem to have tossed it out. It had another plate somewhat like that and used a couple dowel rods to fit together. The thing was rather infamous in the school for being "That One Assignment". It was so bad the instructors gave you this stack of stapled-together sheets if you asked that was about 10 years worth of re-drawn prints of the same thing. I'm pretty sure out of the 20 or so students only 2 or 3 people had the thing even come close to fitting together.
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Mar 18, 2012 19:35
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I feel sorry for you Americans still having to gently caress around with fractional dimensions. We had to do everything in Metric and Imperial on the machinist course I did (Ireland has(had) lots of American companies) but we rarely got a drawing with a fraction on it, just decimals. That said that drawing isn't the worst I've seen, we got a few that were missing crucial dimensions.
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Mar 18, 2012 20:15
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It's funny I was thinking the same thing and how very happy I am to work in metric all the time lately. It is just so much better for building things out of.
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Mar 18, 2012 20:33
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Tooling up my mill with everything China has to offer. Still weighing how much I want everything here, its all from one seller so shipping will come down a lot. Pretty crazy I can get all that stuff for $132 + shipping. 
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Mar 19, 2012 02:12
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This is officially the smallest drill I've ever used or seen in person. #83 drill, .012" diameter. The blue tape is so I could find it against the wood grain of the work bench.
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Mar 21, 2012 03:26
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oxbrain posted:This is officially the smallest drill I've ever used or seen in person. #83 drill, .012" diameter. Air spindle? Or do you guys have a 60,000RPM capable spindle? By the way I ended up getting all that stuff I posted pluss a T clamp kit for $157 + $35 shipping. Can't believe how cheap stuff is for an R8 spindle. Now my BP will have a 3 Axis DRO.
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Mar 21, 2012 03:28
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Bridgeport with the standard variable drive. Redline at 3000rpm, 3100 before the gears start clattering. Effective surface speed at 3100rpm is 9.7fpm. Not ideal, but enough to work. Much more tiny drilling and I'm going to bite the bullet and get a better micro-chuck. My current one has about a thou of runout no matter what I do. Bridgeports are awesome precisely because they're so cheap and you can do so much with one. There's a reason that every machine shop you go in, no matter how many millions of dollars of cnc equipment they have, will have at least one bridgeport sitting around. Do you already have a good test indicator and arm to stick it in the spindle? You'll need it to tram in the head and get the vise lined up. Those coax indicators are good at what they do, but they're pretty limited. Also you're going to need an edge finder, and you might as well get an india stone for the inevitable nicks and dings.
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Mar 21, 2012 06:08
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oxbrain posted:Bridgeports are awesome precisely because they're so cheap and you can do so much with one. There's a reason that every machine shop you go in, no matter how many millions of dollars of cnc equipment they have, will have at least one bridgeport sitting around. Tony Stark had one in Iron Man 2 
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Mar 21, 2012 06:22
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oxbrain posted:Bridgeport with the standard variable drive. Redline at 3000rpm, 3100 before the gears start clattering. Effective surface speed at 3100rpm is 9.7fpm. Not ideal, but enough to work. Much more tiny drilling and I'm going to bite the bullet and get a better micro-chuck. My current one has about a thou of runout no matter what I do. How many holes are you making? I would think for a little more than the price that MSC wants for that micro drill chuck you could get an air spindle and a set of ER16 collets (which most shops already have if they do CNC) and eliminate the run out of the bridgeport bearings and taper (which is probably where half of that .001 is anyway). Anyway, god drat it I knew there was something I was forgetting. An edge finder. I even looked if they had a z touch off block of any sort but forgot about the stupid wiggler. I can get an 8" sweep out of the coax with the longest probe which should be plenty good to tram in the head. The vise is a standard 6" crap vise but again, should be easy to get it within .0005 across the face which is more than I need to be concerned with on the ol' girl. This is a pretty old machine but it does fine for garage duty. However I do at least have a Kurt .0005 increment indicator which I usually use for measuring TIR on the lathe. Fake Edit: I just checked, they dont even have an edge finder. I ordered all that from the same company, theyre base shipping price is pretty high but their combined shipping drops it a lot. Also I dont know if I can NOT buy these for my Lathe: http://www.ebay.com/itm/35-Digital-...=item20bea5571e http://www.ebay.com/itm/12-Digital-Readout-DRO-Quill-w-remote-LCD-Bridgeport-/130633861491?pt=LH_DefaultDomain_0&hash=item1e6a628973 A 2-axis DRO for $100?! Same place sells a Made in USA edge finder for $12 shipped.
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Mar 21, 2012 07:03
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Lord Gaga posted:How many holes are you making? I would think for a little more than the price that MSC wants for that micro drill chuck you could get an air spindle and a set of ER16 collets (which most shops already have if they do CNC) and eliminate the run out of the bridgeport bearings and taper (which is probably where half of that .001 is anyway). Those are too fast. I need 10-20k variable, not 30-50k fixed. The surface speed isn't really a problem, carbide drills are fine running slower. The issue is that the slower I go the harder it is to control chipload. On that one I was just dropping the stop 5-10 thou at a time and dropping it down. I've used that micro-chuck in other spindles that are within 50 millionths and still had it runout a thou. It was a $50 ebay special. It feels grittier than it should. I think the jaw guide and hood aren't hardened and have mooshed with repeated tightening. You don't need anything special to touch off z. Pinch a known thickness feeler gauge or a 123 block. You can do the same for edge finding, but then you have to pay attention to making sure the cutting edge is facing the right way and doesn't rotate when it touches. It's still only going to be within a thou at best, edge finders are just easier. The most accurate will always be to make a cut and measure. I bought a couple edge finders from this guy. Cheaper than starret, easily the same quality. He also makes very nice tap guides.
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Mar 22, 2012 04:34
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I did all CNC and quite honestly gently caress any way that is not a z touch off. So much faster and safer to touch off.
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Mar 22, 2012 05:02
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I've only just found this thread as I thought it was just smithing thread. Welding and fabricating has been something I've enjoyed on projects for a long time. I bought a DC tig set last year and have done a few jobs here and there with it. A couple of weeks ago I did my first bit of welding on stainless, fabricating an exhaust for a friend's Land rover. It was a whole lot of fun. I'm quite pleased with the way the welds came out although they are far from excellent.  I'm toying with the idea of getting a decent AC tig in the future and was thinking about a Kemppi 2300acx, any reccomendations?
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Mar 22, 2012 20:14
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No recommendations but post close ups of those welds, they looks pretty globularly from that pic and people could prob give you some good tips.
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Mar 22, 2012 22:17
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Colonel K posted:I've only just found this thread as I thought it was just smithing thread. Welding and fabricating has been something I've enjoyed on projects for a long time. I bought a DC tig set last year and have done a few jobs here and there with it. A couple of weeks ago I did my first bit of welding on stainless, fabricating an exhaust for a friend's Land rover. It was a whole lot of fun. I'm quite pleased with the way the welds came out although they are far from excellent. That welder looks like it has all the features you would ever need. I like that the Kemppi can do DC or AC that would be really useful if you would be switching between aluminium and steels! But I've never used the brand so I can't speak to the quality and durability of the machine. My personal favorite machine to use is a Miller. It has the smoothest arc of any machine I've worked with and they're durable as heck.
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Mar 22, 2012 23:11
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Judging by your post you are looking for CE models. You should check out some ESAB machines. We have a few in the lab that are pretty badass considering their size. They make them the size of a MIG buzzbox or smaller and have decent output.
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Mar 22, 2012 23:21
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I've only used a couple ESAB machines but I found they were of lower quality. The rollers constantly gave you a rats nest in the machine no matter what you tensioned the thing to. Could have been just the couple machines I used though.
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Mar 22, 2012 23:36
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SmokeyXIII posted:I've only used a couple ESAB machines but I found they were of lower quality. The rollers constantly gave you a rats nest in the machine no matter what you tensioned the thing to. Could have been just the couple machines I used though. We generally hate ESAB as a rule  but that doesn't mean they aren't a leader, ranked with Lincoln, Miller, and Fronius. The hardships we usually experience are often related how damned rear end backwards everything seems to be with their controllers and physical equipment. That is something we have to look past though, because the machines usually perform well and are capable of doing bang-up work if you take the time to get familiar with them, and I'm sure that in the european market much of it makes sense. I know Miller makes smaller dynasty models as well, but I believe they fetch a higher price because of the power of blue. The ESAB machines I have looked at seem to be a lower cost than comparable models of other brands while being a well known brand itself. I'm not sure the reputation of Kemppi machines, though. This is why I made the recomendation to check out a CE based company, as I figure they are much more popular over there. I will check tomorrow, but here are a couple of the tight little packages I'm pretty sure we are using in the shop right now. http://www.millerwelds.com/products/tig/dynasty_200_series/ http://products.esabna.com/EN/home/...2tig_2200i_acdc thecobra fucked around with this message at 00:41 on Mar 23, 2012 |
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Mar 23, 2012 00:30
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http://www.youtube.com/watch?v=2ArhhcgSsm0 "MODERN MANUFACTURING -- COMMAND PERFORMANCE - Department of Defense 1963" This is a nice video about CNC machining in the 60s, making missiles to deliver deadly atoms to the commies.
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Mar 23, 2012 00:58
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Hmm, my only experience with ESAB stuff was a mig my cousin had in his home garage, it was great when working, but after a couple of years (not much use) failed beyond economic repair. Machine wise as I'm in the UK it is just what is available. I've heard a lot of good stuff about Lorch migs, but not much about the tigs. My local welding shop is really great, but they just stock Lincoln, Kemppi , Hypertherm and a few other smaller brands. Speaking of which the Hypertherm plasma I find is a cracking bit of kit to have around the workshop. Going for a decent AC/DC tig set would be a massive extravagance for me and is a bit of a step into the unknown, but I like buying quality if possible and intend to keep it for a long time. Here's a zoomed in picture of the welds from earlier.  I didn't backpurge as I don't have a take off, or a large bottle of argon. The stainless was about 1mm and was welding at about 38 amps. No foot pedal.
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Mar 23, 2012 01:18
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*crashes into thread like blacksmithing Kramer* The tiny buzzbox at Princess Auto is half-price starting Tuesday!!! Yes this Tuesday!! Im gonna weld and I'm gonna cook up calcium carbide and oh goodness I cant wait
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Mar 23, 2012 01:25
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Well Lincoln is always a safe bet. You might look into something like this job: http://www.lincolnelectric.com/en-us/Equipment/Pages/product.aspx?product=K1478-5 It's a heavy old gently caress but for the price I mean come on that's a steal for a brand new AC/DC tig machine. The next step up is another backpack unit like the others I linked, but they're double the price with more buttons to press.
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Mar 23, 2012 01:57
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Pff if you're going to buy heavy and old, do it right.Hypnolobster posted:Unrelated to christmas, something BLUE appeared in our otherwise mostly Red garage.
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Mar 23, 2012 03:41
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thecobra posted:We generally hate ESAB as a rule I've not had any problems with any of the ESABs I've used in the past. I used to use an old ESAB running dual shield and never had any problems. Then I got a Miller suitcase feeder and was like "Later ESAB! Nice knowing ya!" I've used the Miller Dynasty and the Synchrowaves for TIG / Stick work. I like them; they are great machines with excellent control. Of course, my experience with them was in a shop, and I didn't pay for them. When I started doing stuff on my own and was looking at buying a Miller, I couldn't afford it. I got a Thermal Arc. They are Japanese. I love my TA 185 arcmaster. It does everything the Dynasty does and is actually a little less money. Definitely check this unit out if you are going to buy an AC/DC inverter setup.
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Mar 23, 2012 04:21
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