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He's talking about putting an MDF waste board underneath his work, so when the endmill goes through the bottom of his work, it doesn't gently caress up the bed
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Oct 10, 2018 18:51
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So it's 4 inches z total, but the real working z is that minus the thickness of a wasteboard. Makes sense, I guess I read it differently.
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Oct 10, 2018 19:01
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The tool length can affect that as well. My Shapeoko 3 advertised a 3" working Z, though that's essentially the max travel possible on the z-rails from the limit switch until the lower wheels fall off the rail. Once I add a waste board on top of the stock bed and an endmill, that cuts my space for stock to less than 2".
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Oct 10, 2018 19:37
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2” of material and 2” of tool length lets me work from the top of the piece all the way to the bottom. I’m doing a lot of 3d milling of wood for various artsy poo poo and want to do some larger pieces.
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Oct 10, 2018 21:37
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Oh I didn't realize the travel number assumes an empty chuck with no tool in it. I get it now, thanks.
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Oct 10, 2018 21:49
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i've been rolling around adding laser engraving/cutting to my wee shop for a long while now (see last page where I was asking about barrel-bottom ~1W aliexpress dedicated engraving machines) and i'm at a place where i'm probably comfortable enough to tackle a build for something fairly by-the-book patterned off popular existing builds. if that makes sense, anyways. the usual routes i see for doing this cheaply are 1) buying a popular entry-level Chinese model with a big english-speaking user community like the k40 and putting work into getting those chinese-import-level-quality issues smoothed out, 2) doing a scratch build based off existing scratch builds that are well-documented, 3) a kit build that lets you pay for some handholding, and 4) adapt a laser head to work with the spindle of your non-laser CNC machine for occasional work bringing up the distant rear. 4 isn't a real solution for more than occasional vector marking on non-metal materials so that's out. I'd be looking for ~40ish watts minimum and ideally a 12x12" or bigger cutting area, and compatibility with decent software that can handle stuff beyond just vector cutting (quick raster engraving and the like) would be ideal. A K40 is my benchmark here because it mostly meets the above and I can get one from a Chinese seller for ~$600-750ish shipped. I know they've got a lot of issues but core improvements like upgraded controller software are easy enough to tack on from the get-go, and there are builds online specifically for improving and expanding K40s if I wanted that down the road. The priced-out builds or kits that seem to meet the above will run me more than a K40 will but at least the build quality and machine suitability for my needs is a given with that. All this to say- anybody taken this dive before who can recommend an approach from the above, anybody know of any good kits or thorough builds that aren't prominently-ranked for the expected google searches, words of laser build wisdom, etc?
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Oct 11, 2018 00:50
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Have you priced out an exhaust system?
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Oct 11, 2018 02:01
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I worked out an expected price range for DIY solutions, priced out a commercial filtration system I'd actually stake my health on, and was despondent until I realized I'm well set up to just vent directly outside with an exhaust fan and a duct passed through the external building wall. the hole, ductwork and exhaust fan are already in place thanks to some modifications I so sagely had done during renos a few years back, it was originally a fume extractor for soldering.
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Oct 11, 2018 05:28
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Don't pay more than 3-400 for a stock K40. Even when you add on a DSP controller it's tough to beat at about 1k. Made a replacement tabletop for the dinette in our RV:  Made from red oak, cedar, poplar:  Glued together, then used pins in the wasteboard so I could reposition it in Y to let me cut an area larger than my machine travels. The perimeter cutout was two toolpaths, but the positioning was close enough that you can't see a seam between them.  Stained it. The v-carving doesn't photograph well with the dark stain.  First time using an epoxy coat was interesting. I didn't seal the backside of the table well enough and got some small bubbles. Nobody else seems to care but I will sand it down and recoat at some point.
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Nov 27, 2018 05:27
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Was having a real downer evening. My lathe's z-axis endstop kept tripping from motor/VFD EMI. So I cut the wire, ran a braided copper sleeve over it, resoldered everything, got it looking good. But when I went to test, it actually had made the problem worse -- EMI would instantly trip the endstop when I flipped on the VFD, no matter what spacial configuration. Tried a dozen bad positions until I realized I needed to ground the copper braid. Doh. So maybe this will save some lurker a headache: when you're shielding wire, always connect the shield to ground.
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Dec 11, 2018 06:55
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Mofabio posted:Was having a real downer evening. My lathe's z-axis endstop kept tripping from motor/VFD EMI. So I cut the wire, ran a braided copper sleeve over it, resoldered everything, got it looking good. But when I went to test, it actually had made the problem worse -- EMI would instantly trip the endstop when I flipped on the VFD, no matter what spacial configuration. Tried a dozen bad positions until I realized I needed to ground the copper braid. Doh. So maybe this will save some lurker a headache: when you're shielding wire, always connect the shield to ground. Only ground one end of it, though! (Do it on the more "power supply end" side not the "sensor / worky end" side)
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Dec 12, 2018 00:43
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The Eyes Have It posted:Only ground one end of it, though! (Do it on the more "power supply end" side not the "sensor / worky end" side) That side won out by pure
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Dec 12, 2018 02:38
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I'm in the process of refurbishing a commercial CNC router that died a death due to an electronics failure - our company were scrapping it so it found its way into the boot of my car. All the mechanics are still good. I've managed to get the x,y and z axis working nicely with a simple Arduino + GRBL shield for now but am struggling with finding something to drive the 3 phase spindle. The spindle is a Jager Z33 unit and Jager have kindly provided me with the user manual. It requires a 'Frequency converter' to drive it according to the manual, minimum speed is 4V, 2.4A @ 167 Hz (10,000 RPM), maximum speed is 56V, 5.3A @ 1667Hz (100,000 RPM). I'm struggling to find an appropriate frequency converter, the units I've found so far rated to the appropriate current give a 230V output rather than the lower voltage specified on the data sheet. Can anyone recommend an appropriate driver for this spindle? It's currently completely stripped down to clean out all the FR4 dust from everything, but once that's done I'll post some progress pics.
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Jan 4, 2019 13:00
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I know absolutely nothing about CNC machining. I do a lot of 3D printing, but I know that's a completely different kind of process. Say I were interested in manufacturing relatively small metal parts. For instance, something like the metal rails on this handheld device:  What's my best option for doing this with a machine I can run in a hobby shop / garage in my home? I'm assuming the answer for this kind of thing is that some kind of water cutter on sheet metal is going to be the better option, right? Then again, I hardly know what's out there.
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Jan 9, 2019 07:39
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Inazuma posted:I'm in the process of refurbishing a commercial CNC router that died a death due to an electronics failure - our company were scrapping it so it found its way into the boot of my car. All the mechanics are still good. I've managed to get the x,y and z axis working nicely with a simple Arduino + GRBL shield for now but am struggling with finding something to drive the 3 phase spindle. It's an ac frequency converter? Generally lower voltage ratings like that are DC drives. NM. It does say it's an AC asynchronous motor. Looks like Emerson makes a 3000Hz AC drive the M700 line. I'll have to dig around more for more affordable options. EvilBeard fucked around with this message at 08:16 on Jan 9, 2019 |
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Jan 9, 2019 07:58
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Harvey Baldman posted:I know absolutely nothing about CNC machining. I do a lot of 3D printing, but I know that's a completely different kind of process. You're looking at minimum $200 for anything professionally CNCed, metal laser cut, or waterjet cut. Have you looked into Shapeways metal? Or just plastic with some good chrome paints? Or paper stencils on some sheet metal and careful file work.
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Jan 9, 2019 08:09
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I'm thinking I might need a few hundred sets of these parts, which is why I've started wondering about the cost of investing in home machines that might be able to make them. I'm guessing from what you're saying that the economical option would still probably be to farm that kind of thing out to a professional service anyway?
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Jan 9, 2019 08:25
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It might be. Can we get some better pictures or a print of the part?
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Jan 9, 2019 08:42
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Harvey Baldman posted:I know absolutely nothing about CNC machining. I do a lot of 3D printing, but I know that's a completely different kind of process. We'd need more details/better pictures of the part, but I suspect that's a sheet metal part that's been bent to tight tolerances to give it some engineered backbone. In any case, none of the CNC metal sheet cutting techniques are practical for garage operation; I'm not aware of a hobbyist-level waterjet solution, nor a laser cutter capable of cutting metal. You could get the parts laser cut and then bend them yourself with a brake (assuming that's necessary/part of the design), but if you don't already have a quality sheet metal brake and know how to use it, getting the bending done by someone else as well will likely be cheaper and easier. TBH making these in your garage probably won't ever make sense if we're talking about quantities of a few hundred and you'd be getting the tooling set up from nothing.
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Jan 9, 2019 18:28
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That's totally a piece from a movie prop but I can't remember which. Some sci-fi thing I think.
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Jan 9, 2019 18:36
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It's the portable Voigt-Kampff scanner from the new Blade Runner movie. e: or just an iris scanner, I guess. Still, it's for detecting replicants.
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Jan 9, 2019 18:50
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Another thing- if you're used to 3d printer you're probably not used to designing products with the material stock in mind, but it's the path of least resistance when not all designs are equally-easy to fabricate. In this case, for example, that part likely has rails integrated into the chassis because that's practical using the full scope of modern manufacturing techniques appropriate to mass production. If you don't have a factory in Shenzhen at your disposal, though, that may not make sense. A much simpler, garage-friendly approach might be simple round tubing that telescopes open/closed- maybe no machine tools needed at all, just a hacksaw/cutoff disc and a reamer (and an overall design that plays nice with this sort of rail).
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Jan 9, 2019 18:52
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OK, I realize I probably didn't provide enough information. Sorry. I was trying not to get too caught up in it. It's a portable Voight-Kampff scanner from Blade Runner 2049. I've been working on making them as replica props with working screens and the whole dumb slide mechanism. Here's some references of the original prop:    I think I actually did track down the linear rail used on the back - I think it's one of these. Thing is, that fucker is $100, and I don't actually need a working linear rail for just that bit, just something that looks like one. I have worked up my own latching mechanism for now. The one I modeled has a central piece that's about 4.5mm wide, and two additional thin outer layers that are maybe .75mm thick each.  It works as 3D printed parts, and right now my plan is to try casting the printed prototypes in epoxy resin, but there are some rather thin parts on that rail design that I'm not entirely sure will be reliably castable. Ideally, I'd love to make the outer parts of these rails out of metal, if not the entire thing. Making the 'catch' part on the latch mechanism metal would also be great because then I wouldn't have to worry about the mechanical stresses involved on a resin part. Plus, if the parts were actually metal, that means I wouldn't have to spend time painting resin parts to look like metal. I've got a bunch of people who are interested in maybe buying copies of this, so I'm working on all of this with an eye to 'how can I reproduce this en masse in the best and easiest way'. I'm not against the idea of throwing money into maybe getting the parts made professionally somewhere, although I'm not sure where or how. That said, I figured if I was going to throw significant sums of money at that kind of thing, maybe it'd be worthwhile to look into seeing if there was some kind of home CNC/waterjet machine available in a reasonable price range that could pull this kind of thing off. It wouldn't need to be too big in terms of work area.
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Jan 9, 2019 19:59
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You could make something very similar out of aluminum bar stock and one of the inexpensive desktop CNC mills from eBay or AliExpress. They're slow, and aluminum is about the hardest material they can handle, but that is a very tiny part so the cutting forces will be low, and it's only like two operations. You could make a hundred of the parts over a week or two without much trouble once the machine is set up. I have no experience personally with the cheapy chinese mills, but I've bought other products from SainSmart before so their 3018 model might be worth a try: https://www.amazon.com/SainSmart-Genmitsu-Control-Engraving-300x180x45mm/dp/B07DBY44KJ/ With a mill like that, you might also consider using an engineering plastic like delrin, which is strong and tough and machines very nicely on low-powered machines with sharp tools. Delrin is also self-lubricating which is great for a sliding mechanism. It's going to be more flexible than metal but that might not be an issue for the design, and it will absolutely be tougher than a cast resin part.
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Jan 9, 2019 20:27
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Sagebrush posted:You could make something very similar out of aluminum bar stock and one of the inexpensive desktop CNC mills from eBay or AliExpress. They're slow, and aluminum is about the hardest material they can handle, but that is a very tiny part so the cutting forces will be low, and it's only like two operations. You could make a hundred of the parts over a week or two without much trouble once the machine is set up. Awesome. This was kind of what I was hoping to hear, though I wasn't sure if there was a good option. Would this be able to do the thicker parts out of aluminum, you think? Like, the main 4.5mm section of the rail?  Delrin sounds great, but really my worry about these things has to do with having to paint them. If I paint them, and they're sliding parts, that paint is not going to stay on there very long, and the paint may well gently caress with some of the sliding over time.
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Jan 9, 2019 20:41
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Harvey Baldman posted:Awesome. This was kind of what I was hoping to hear, though I wasn't sure if there was a good option. If you can deal with a small (~5.5x11" ish Y/X) working area a Taig micro mill would be a good fit, it's above and beyond the cheapest "real" milling machine you'll find and will have much better rigidity than comparable gantry-type mini routers which struggle with aluminum. I've got one, you can cut steel at modest chiploads no problem, and with aluminum the issue will be tool deflection before machine deflection until you're running end mills up near 3/16-1/4" dia. All that being said, though, getting a machine like this up and running accurately and repeatably is either disproportionately expensive or will be a more ambitious and time-consuming project than running these parts will be, and certainly more expensive than farming it out to someone with a machine that's actually ideal for this purpose (commercial laser/waterjet job shop). That's also leaving aside "learning to machine effectively on a very small mill", which is daunting in its own right if you don't have prior milling experience. If you're dead-set on doing these yourself with a home setup, it should probably be best viewed as a job to spur on and bankroll a new manufacturing toy, as opposed to viewing the mill as the most appropriate means to and end, because the latter will probably lead to a lot of frustration. (i say this because i basically did that exact thing, and i don't exactly regret it but that's down to luck and circumstance, and it 100% was not a sensible solution to my manufacturing problem)
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Jan 9, 2019 21:20
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You can put together an email with your BOM, quantites, and CAD and send it to a place like protolabs to get a quote within a week or so. That would give you a dollar amount to estimate an ROI of tooling up your own shop and becoming a manufacturer for this project. They'll give you a price to deliver the material in the shape you want so you'll have to account for secondary ops like polishing, coating, fitting, etc. A lesson we learned is to call out a lot of "good sides" in the part drawing because they are very creative about where they leave tool marks. Also, from the image you posted I think my favorite machine is a good choice for those parts: https://youtu.be/HBa1wDv-6bU bred fucked around with this message at 22:14 on Jan 9, 2019 |
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Jan 9, 2019 22:08
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Repeating my suggestion of Shapeways, too. They can print in metals and quote you just by sending an STL
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Jan 9, 2019 22:26
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How closely do you need to replicate it? You could use a steel pin with a full-length flat, or D-profile shaft, in place of the rail. Let the circular side slide on two internal 3D printed v-ways: that's 4 degrees of freedom knocked out, the shaft can now either go up and down or rotate. To knock out the last DOF, leaving it w/ one (sliding up and down), have a ball or cylinder ride on the flat side of the pin. Either the v's or the ball has to be spring-loaded to apply pressure against the pin, in order to nest (make the force >2x gravity*mass of either side). I think even using McMa$ter this is <$10 in parts per unit, w/ no metal cutting tools except a Dremel.
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Jan 10, 2019 09:54
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There are definitely a million ways of making it work as it's supposed to on the cheap, but given that the thing is a replica movie prop (and he's been developing this in various threads for like a year or more now), I'm guessing that having the exact appearance is pretty critical.
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Jan 10, 2019 16:56
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Sagebrush posted:There are definitely a million ways of making it work as it's supposed to on the cheap, but given that the thing is a replica movie prop (and he's been developing this in various threads for like a year or more now), I'm guessing that having the exact appearance is pretty critical. It's only gotta look the part in the exposed area tho yeah? My guess is the matching McMaster linear rail is pretty much the price that it is. Not going to be able to make it much cheaper (and probably even more $$ all said). That's why I was asking how close it's gotta be, where he could compromise... Cuz if he just wants something metal that slides then that can be done hella cheap. A 1/4" D-shaft's about $4 a unit and can be disguised, since the sliding mechanism lives inside the unit. He could grind down the other 3 faces to match the rectangular rail, then paint the rail's indent down the side... a $50 belt grinder and fine brush is cheaper than a Taig, not that that's not a sweet machine. Mofabio fucked around with this message at 21:39 on Jan 10, 2019 |
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Jan 10, 2019 21:01
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I'm trying to wrap my head around how you would measure that two linear rails are: 1) parallel 2) level For leveling would you use a straight edge and a machinists level? For parallelism, I haven't the faintest clue. Would you have an indicator on one rail measuring the other? Or would you have like a reference straight edge in between the two and then measure the distance between that to either rail?
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Mar 5, 2019 19:06
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I would probably screw a dial indicator into a 1-2-3 block and slide it along one rail while measuring the other, yeah.
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Mar 6, 2019 00:40
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For parallelism, measuring the distance between the two features in a few places with calipers or whatever is good enough for most applications. Flatness you can tell with a straight edge or scale or anything that's really flat.
Volkerball fucked around with this message at 01:26 on Mar 6, 2019 |
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Mar 6, 2019 01:23
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For the 2D alignment, you can measure the X across the rectangle. Check member straightness with a straight edge. For the height, you can use a dial indicator. A low tech way they use to flatten frames is pulling two strings across the X and seeing how they lay. Imagine doing a simple cats cradle with your hands to get an idea.
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Mar 6, 2019 02:33
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Sagebrush posted:I would probably screw a dial indicator into a 1-2-3 block and slide it along one rail while measuring the other, yeah. This but a magbase for the dial indicator. Measuring at a few points won't show everything.
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Mar 6, 2019 11:21
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cakesmith handyman posted:This but a magbase for the dial indicator. Measuring at a few points won't show everything. Unless you're on a calibrated granite table, sliding a 123 block around isn't going to be accurate to a higher precision than calipers anyways. Calipers will show you .005" TIR no problem, and odds are extremely high that dudes part will function if it's within that. I don't know if he's milling out these rails or what, but if he just milled a line from X0 Y0 to X0 Y5, there's really only a few reasons why it wouldn't come out as a straight line, and you can diagnose any of them with calipers, a square, and a good look at the finish. Volkerball fucked around with this message at 01:23 on Mar 7, 2019 |
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Mar 7, 2019 01:18
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He's measuring the separation between two rails, though. Doing that with handheld calipers isn't going to be super accurate unless you're inhumanly good at compensating for cosine error. And it doesn't matter if the table is flat. Stick the dial indicator on a 1-2-3 block, push the block up against the inside of one rail, align the indicator on the other rail, slide back and forth. Tiny bits of vertical movement won't noticeably impact the reading unless the rail surfaces are non-perpendicular.
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Mar 7, 2019 01:44
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It doesn't take super human skills to tell that the gap is .003" wider here than it is over there with decent calipers. I can't really picture his part since he didn't give any details, but 90% of the time, checking it in a few places with calipers will be enough to determine if you have an issue and what that issue is. I would only really do what you're describing if the rails are so flimsy that they actually flex under the force of opening the calipers, and/or there was parallelism callout of .003 MAX or tighter, which is uncommon.
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Mar 7, 2019 02:12
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Also, if your rails need strict aligning beyond tramming, your system is probably over constrained.
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Mar 7, 2019 19:55
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