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Burger smasher project continued today, M8 bolt connects it to the knob, I have ordered some PTFE round stock to make a heat shield from that I can put between later. Knob could have been larger but it's what I had available without starting cutting up bigger pieces. 
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Oct 23, 2019 18:46
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that'll smash some burgs, I reckon
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Oct 23, 2019 18:57
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Hell yeah, that looks pretty dope.
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Oct 23, 2019 19:36
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Isn't ptfe pretty bad w heat tho
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Oct 24, 2019 02:04
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It's fine up to about 220C (430F).
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Oct 24, 2019 02:07
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If you really wanna dissipate that heat, a few leather gaskets/o-rings would work between the steel and ptfe as well
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Oct 24, 2019 02:38
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I've figured out how to do what I'm trying to do with mostly wood so these questions are mostly academic, but I'd still like to know. 1) For a rod of given diameter, is it stiffer/more rigid as a solid bar or as a tube? In this instance, I wound up using 1/2" pipe because it was cheap etc, but would a solid bar of the same OD (~7/8") be stiffer? Or is it that for the same weight of material per foot, that material shaped into a tube would be stiffer than if it were solid? 2) Is drilling/tapping mild steel/aluminum difficult and what do I need to know and what's a decent tap/die set for me to learn on/gently caress up. 3) Are little harbor freight metal lathes work a drat? There have been a few things recently where a metal lathe (assuming I learned how to operate it properly? I got a reprint of some old book published by South Bend IIRC called "HOW TO RUN A LATHE") would have been real useful. Or for the money is old iron hands down better? This would just be for odd bits of manual metal machining in support of my woodshop/for loving around with. 4) Aluminum will gently caress up my bench grinder wheels right? or is that brass?
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Oct 24, 2019 03:35
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1) A solid bar of a given diameter is stiffer than a hollow tube of the same diameter. A hollow tube with the same cross-sectional area as a solid bar of the same material will be significantly stiffer (because it's much larger around). 2) No, not hard. Use tapping fluid and go slow. Get whatever taps and dies are top sellers on Amazon. 3) The little 8x10 lathes have quite a following but if you have the space and money and logistics for a South Bend or whatever, and you find one in good shape, you won't be disappointed. There are lathes from a hundred years ago still running perfectly today. 4) It's both, but especially aluminum. Use a belt sander for those materials instead of a grinder.
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Oct 24, 2019 03:42
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shovelbum posted:Isn't ptfe pretty bad w heat tho It's what they use on tig torches as heat shields so I figured it will work in this case too. And they coat frying pans with it.
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Oct 24, 2019 04:11
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Kaiser Schnitzel posted:1) For a rod of given diameter, is it stiffer/more rigid as a solid bar or as a tube? In this instance, I wound up using 1/2" pipe because it was cheap etc, but would a solid bar of the same OD (~7/8") be stiffer? Or is it that for the same weight of material per foot, that material shaped into a tube would be stiffer than if it were solid? Ambrose is correct, but to cover this a bit more fully because I feel like writing about math: the stiffness of a round bar in bending increases with the fourth power of its diameter. That is, if you double the diameter of a solid bar, its stiffness will go up by a factor of 16 (the relative math is the same for torsional stiffness, if you're trying to twist the rod.) That's because as you bend the rod, the parts of the rod that are furthest away from the center are the ones that have to stretch the most, and thus what contributes the most stiffness. Let's say you've got two rods of equal length and the same material. One is 1" diameter, and the other is 2" diameter. The 2" piece is 16 times as stiff (meaning that to cause the beam to bend some given amount you have to push on it 16 times as hard), but it's also 4 times as heavy. What happens if you drill a 1" hole in the center of the bigger rod? You get rid of 1/4 of the weight. But you only lose 1/16 of the stiffness. So now it's only three times the weight of the 1" rod, but it's still 15 times as stiff. That's a pretty good deal. Similarly, if you drill a 1.5" hole, you remove 56% of the mass, and the stiffness goes down 32% (1.75x the weight of the 1" rod, 10.9 times as stiff.) And so on. I may have typo'd a couple numbers, but the basic principle is hopefully clear. Theoretically, to optimize the stiffness/weight ratio for a tube you'd want infinite diameter with infinitely thin walls. In reality, you're limited not just by space concerns, but also by the need to avoid crushing the tube when you apply load to it. So in reality you get decreasing returns as you shrink the wall thickness. That strayed a bit from your original question. But in summary: yes, your second comment is correct: tubes are more efficient weight-wise than solid rods.
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Oct 24, 2019 06:18
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How about in torsion?
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Oct 24, 2019 12:08
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As an owner of a mini lathe, there's a lot it can do, but the moment I find myself able to upgrade to something bigger I'll do so. Take that for what it's worth.
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Oct 24, 2019 13:33
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Mine is a really nice size length wise. don't see myself needing more than the 650mm between centers. I only wish it had more height capacity, and a longitudal feed that wasn't just the half screws, and a bigger spindle hole. Oh well I can't really complain, it's a good lathe. Just not perfect.
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Oct 24, 2019 14:56
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needed a hammer loop for my belt w short notice so i knocked one out from 1/8" copper wire in 15 minutes- i didn't expect it to hold up but I peened the poo poo out of it for work-hardness and it's serving just fine, a couple Corrective Adjustments in the field aside   aside from using 3/16" brass or nickel silver next time, I'd also probably extend each of the clip terminals downwards another inch, inch and a half parallel to the wearer's leg before scrolling the tips- a heavy hammer twists the clip + belt downwards, so some integral bracing beyond the belt to resist that rotation ought to help (and is in line with commercial hammer-loop designs that just use a larger 'plate' instead of individual wire legs)
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Oct 25, 2019 00:13
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sharkytm posted:How about in torsion? The math for relative changes in stiffness/weight work out the same. For a solid rod, both torsional and bending stiffness are proportional to the 4th power of diameter. So all the numbers in my second paragraph work out the same. That helps you if you've got some idea of the stiffness of something and just want to know what'll happen if you change its size. If you don't have any reference and want to know the stiffness in an absolute context, the math is different for torsion vs bending. The math for calculating the absolute stiffness of a rod are different for bending or torsion. This link shows the math for torsional stiffness briefly: https://www.bu.edu/moss/mechanics-of-materials-torsion/ And this one covers bending (this is more complicated, though, bending is more difficult to calculate.): https://www.bu.edu/moss/mechanics-of-materials-bending-normal-stress/ To get extremely and obnoxiously technical, though: the last equation for torsion of Φ=(TL)/(JG) calculates out the compliance. The static stiffness of some point in a structure is defined as the amount of force necessary to move that point by some amount (e.g., you may need to apply 10 foot-pounds of torque to twist a tube by one degree, giving a stiffness of 10 lb-ft/degree.) Compliance is the amount something will move when a force is applied to it, and it's the reciprocal of the stiffness (that same example has a compliance of 0.1 degrees/lb-ft.)
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Oct 25, 2019 01:42
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So maybe some of you guys know that oily brownish sludge that you get when you clean out a really old sump on a machine? Well I dropped my phone into that. It survived and I had it apart to check the circuit board and it looked fine, but the crap got into the exposed speaker membrane and now it sounds like crap at high volume.
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Oct 28, 2019 13:54
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Magnets will remove any metal fillings. I had to do this regularly with my old HTC Evo.
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Oct 28, 2019 14:29
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I’ve got to weld up some long toolrests for my wood lathe and am a little rusty. They will be 1/4”x1.25” angle with a 5/8” round rod welded to the top of one leg of the angle and posts welded to the other that go in the banjo. I ordered cold rolled steel for the rod because it’s smoother (and harder?). Does it weld just like hot rolled? I’ll be stick welding with a Lincoln buzz box-I think I have 6013, 6011, and 7018 electrodes floating around if one is better than the other. Is cold rolled steel any stiffer than hot rolled? I’ve always been a little confused on the differences.
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Oct 29, 2019 04:33
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Cold rolled welds nicer than hot rolled because it doesn't have mill scale. Less prep and all. Strength is higher in the same alloy that's cold rolled, but it often has internal stress that can cause deformation during fabrication.
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Oct 29, 2019 04:45
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As I alluded to earlier, I cleaned out the sump on the FP2, been putting it off because it was nasty work.    Corner to the left was difficult to reach    This is what the pump sucks up fluid through. When I got it up it was covered in brown goop but also wrapped with a fine mesh held in place with steel wire. Looked like an addition after the fact.  Inside was a coarser mesh that looked factory installed, I removed it and used the finer mesh to make a new one that fit inside instead.  I'm not quite done with cleaning the sump out yet, once the machine is back together and the pump is running I will fill it with warm water & potassium hydroxide and flush it out. After that... I am not sure, use the machine with coolant or not... I have before used Ballistol and water in a squirt bottle, this worked well and never rusted anything on my lathe. But this summer I bought commercial coolant concentrate and mixed up that in a squirt bottle and it's nasty stuff man. Attacked the zinc coating of some sheet metal coversI had made for the lathe and left a sticky residue and caused rust. I really thought a comercial solution would have been better than my homemade ballistol mixture. I am not at all wanting to use up the keg of concentrate I bought if this is how it behaves. Been thinking if I can sell it. I've heard some people use neat oil in their coolant systems instead, apparently it lasts decades, just topped up now and then. And never any rust issues. But you don't want to use it with cast iron then, and it smokes and is messier and has no real cooling effect. I do think the few times I would want to use coolant I would want it for the cooling effect too. I've also considered making my own fog buster instead and move it between the lathe and mill, that would use a lot less coolant and make less of a mess. But it also feels like a waste to have two machines equipped with coolant pumps and not use it...
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Oct 29, 2019 05:36
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I got an old axe when my grandma passed away recently, it was my grandfather's for chopping wood for the fire. I go camping every so often so decided it'd be a good project to restore it as the handle was also stuffed. It was rusty (typically, I didn't get a before shot, but it was reasonably rusty) Step 1: rust removal w electrolysis  Finished  In progress  Closer to start  Flocculated rust The next step is to give it a clean with grinder, flap wheels, and then hand sanding. I do really like the black oxide look, but I want to smooth it back to a nice finish. Maybe I'll season it like a cast iron pan but with some old engine oil or something). The plan for the handle is a stainless core "tang" which runs the full length of the handle, some brass or stainless tube and epoxy mosaic pins, and a couple of Australian native hardwoods to make a handle. Either finger jointed into a longer stock and shaped, or thinner pieces laminated into a kind of plywood look with alternating colours. I've got access to multicolour ply from Finland as an option as well but I'll decide as I get closer to that stage
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Oct 29, 2019 07:41
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Anybody have much experience with 1) delft clay sand-casting, or 2) kirksite ( zamak 2 alloy when used as a die-forming tooling metal)? If so, probably skip to the bottom of this unwieldy post. most of htis post is entirely extraneous to my question but i wanna get it out in writing anyways, feel free to skip most of this: ----- For months now I've been puzzling over the best process for rapidly making detailed 3D dies starting from CAD/3D models, specifically for use with the rubber pad forming sheet metal embossing technique. I've def posted about it before, buuuut for the casuals among us: Rubber-pad forming is a sheet metal embossing process wherein the tooling consists of a single conventional positive or negative die matched with a block of rubber/polyurethane, which acts a "universal mating die" that conforms to whatever die design you're working with. It's ideal for short production runs, prototyping, jewellery, and any application where you want to bridge "handmade/unique goods" with "extremely fast production by artisanal standards" and also "a decent standard of repeatability and process control". The real bottleneck for production is tooling, no surprise there. It's also a technique that hasn't changed a ton since the 80s or 90s, I was in a jewellery studio last week and people were still working out of the (admittedly excellent) book Hydraulic Die-Forming for Jewelers and Metalsmiths, the ~40 year old text that introduced hobbyist-tier metalworkers to a little slice of modern manufacturing. It's a great resource, but it's also needed a couple new chapters added for the last decade or two. ANYWAYS I've got the simpler half of my Budget Rapid Tooling Process worked out to great effect, I was posting about it earlier this year- I cut dies from acrylic sheet on a laser cutter, either silhouette dies for making organic pillowed forms, or simple "2.5-D" dies made by raster-engraving the poo poo out of some acrylic until the desired depth is achieved, for ex  Detail constraints aside, I can design a small sheet metal part, draw and cut the tooling, and produce a prototype run (a dozen units, say) starting from nothing in, like, 20, 30 minutes if the design is simple. It's a really powerful technique. But real detail, stuff like detailed bas-reliefs or fully-representational 3D renderings, isn't possible with slices of acrylic. But there ARE other, fairly novel hobbyist-accessible manufacturing techniques that *do* permit this sort of detail. cnc milling either positives or dies directly is immediately ruled out due to cost/time/the usual toolpath n feeds/speeds bullshit; if we want to start from a .stl/.obj file, that leaves us with additive manufacturing processes. FDM 3d printer filaments are just not strong enough to be used directly as press tooling. The handful of viable exceptions- wacky poo poo like metal clay-style printer filament that's just metal powder in a burnout binding agent, so you can print something and then sinter it in a kiln into a homogenous piece of metal, or laser sintering processes, stuff like that- are v expensive at the sheet metal die scale and not suited to experimenting with. Same thing w resin feedstocks. Then I moved on to using additive processes to make wax positives for investment casting burnout. This one is perfectly viable, but investment casting is its own pain in the rear end that I'm strongly trying to avoid, and one that doesn't really seem necessary for the sorts of objects I'm trying to cast (large by jewellery standards, single-faced designs with flat backs, and no undercutting to speak of). if it's gonna involve casting, it doesn't have to be hot, cold can work too. steel-filled liquid epoxies are an old standby for making serious rubber-sheet tooling, poured into flasks w positives at the bottom to produce good-quality dies all at once. this technique is pretty good and is often referred to as still being the 'gold standard' for this sort of tooling, but again, cost is a big barrier. A pound of liquid steel epoxy would run me almost $100 and would only produce a couple of dies. Again, I don't want to make tooling that'll last for 10 000 press cycles, I want easy, quick and low commitment so I can knock out 10 dies in a day and not sweat about the cost. Cheaper non-metal-filled resins are tempting, but again seem not mechanically up to the task of press tooling. So let's say I'm resigned to real-deal molten metal casting for these dies. Which metal to go with? Needs to be strong and hard-wearing, but I don't have a melting furnace so high-temp stuff is out, and it's also much easier + safer to work w low-melt metals in general when casting. Aluminium is everywhere and cheap, but you need a proper melt furnace to work with it. I could go the other way and use low-melt "tooling alloys" like linotype metal, maybe even a fusible alloy like Wood's metal where I can do my "melting" in a pot of boiling water in the kitchen and recast the die a hundred times with no loss. Nooooot a big fan of cadmium and lead all over everything i make, though, and fusible alloys are still very soft by metal standards + will not hold detail for long. If only there were a low-melting alloy with press tooling characteristics. turns out there is!! zamak 2!! alloyed explicitly for use as small-run sheet metal tooling!! think that's it ........... so the question. the challenge is to produce high-detail, high-finish-quality complex 3D forms for use as casting models as cheaply and quickly and as flexibly as possible, and then use that form to produce proper metal tooling through a casting process, also as quick/cheap/flexible as possible. My solution is: use resin 3d printing sparingly to produce just the high-detail areas, build up the rest of the tool using more economical approaches like "glue it to some Masonite board", and then cast the dies from kirksite zinc tooling alloy into delft clay moulds, i.e. fancy-pants prissy sandcasting process for jewellers where the sand component is very fine-grained clay. you get very good surface finishes right from the mould and the sand is endlessly reusable, but you're still subject to the usual sand-casting two-part mould limitations, which seem acceptable for my purposes. the proposed process, quoted from 3d printing thread: Ambrose Burnside posted:- use resin printer with a normal non-burnout medium to produce just the detailed 3d components of a given tool; if i were making a bas-relief medallion, for example, id get just the sculptural art embossed part of the medallion printed down to a depth of like 0.1" or so to produce a "detail disc", ignoring the rest of the medallion + overall die geometry 2500 words later: before I go and spend a bunch of money on Delft clay molding sand and kirksite ingots, how does this approach sound to people w casting experience? any pitfalls w the clay sand or kirksite that I wanna know about in advance? any Reckons on ways to improve hte process? Ambrose Burnside fucked around with this message at 05:17 on Nov 1, 2019 |
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Nov 1, 2019 05:03
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I'm reading/responding while I'm struggling with sleep, so apologies if I talk about something I missed in your post. As far as I understand your post, you got this cool embossing technique, but you're kinda stuck with making stuff to the same depth, restricted by the fact that mainly your laser cutting takes away all the acrylic or nothing (rastering aside). You'd like to get more varied heights in the work in the same runs of 20-30.That's end goal, right? Would you not get the detail desired if you used your current technique of laser cut acrylic but doing multiple thin layers stacked up, almost like the elevation lines of a topographical map? If you're using a soft mating die, I'd assume the metal wouldn't strictly form those contour lines and would smooth out. Might take some more time in set up if you need to use registration pins or whatever, but that's still a one time deal for a run. You kinda figured out the acrylic dies, you're already set up for it, no new equipment or anything.
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Nov 1, 2019 11:21
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Instead of using a hot alloy, could you use a high-durometer urethane? Start out with a 3d print master, make a flexible urethane two piece mold, then fill it with something like 80D Onyx ($25 / kilo)? edit : That Stratasys plant I toured 3d printed dental training sets. They used the 3d print to make a urethane mold, then cast it in some super hard dental simulation poo poo so aspiring dentists could gently caress it up instead of volunteer teeth or whatever. It was really tough poo poo.
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Nov 1, 2019 14:54
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Rotten Cookies posted:I'm reading/responding while I'm struggling with sleep, so apologies if I talk about something I missed in your post. In general I’d like to improve on acrylic across the board, i def didn’t articulate that in my post. I already build up “terraced” dies like you said, but the level of detail and representation available to me is a magnitude smaller than I want. That sort of construction isn’t practical for the fairly small, high-detail embossing s I want to have access to. In addition, acrylic -works- but it’s far from ideal. It’s too soft, it lacks rigidity. It deflects and compresses under higher tonnages and doesnt bounce back. Any fine details or sharp edges on dies become heavily rounded off within a few parts. Those finicky thin-slice terraced dies? they take the longest to put together and also have the shortest useful tool lives. It’s a great material for “roughing in” overall embossed forms and creating volume but it sucks for small fiddly work and ultimately isn’t suited for actual production runs. A zinc alloy die would be a huge improvement in terms of stability and longevity such that I’d reproduce acrylic dies i liked, even the “well suited” ones.
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Nov 2, 2019 00:34
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Yooper posted:Instead of using a hot alloy, could you use a high-durometer urethane? Start out with a 3d print master, make a flexible urethane two piece mold, then fill it with something like 80D Onyx ($25 / kilo)? Because the secondary "conforming die" is already a fairly hard urethane (up to 90-95A duro for crisp impressions), the primary die must have minimal deflection under load or else you stop getting good definition and can't really control the process, so urethane tooling isn't practical except for two-part conforming moulds (which are also viable, but being able to get away with a single simple tool is part of what's good about the technique i'm using). THAT SAID, I did manage to somehow miss that there are non-urethane mineral-filled epoxies like smooth-on's epoxacast 650 which are purpose-formulated for lower-stress sheet metal tooling, and which are cheap enough that the non-reusability isn't a dealbreaker (12lbs for ~$80 CAD, for example). definitely inferior to zamak cast tooling, but we're still talking over twice the hardness of acrylic sheet. I might start with that, largely so I can sidestep the melting pot and casting sand I'd also have to buy to do much experimenting w metal tools.
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Nov 4, 2019 17:03
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Gang tag contest! https://forums.somethingawful.com/showthread.php?threadid=3903115
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Nov 5, 2019 18:49
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Hot knife gang
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Nov 6, 2019 03:35
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Metal melters/chip eaters/clangers In an unrelated matter: I got myself a fume extractor and the motor on it _seems_ to be both single and 3 phase?! . I’ve got it working on 3 phase but it’d be more convenient if I could run it on 240v single phase. Here’s the motor: https://www.amazon.com/ABB-Motors-MT71A14F85-2-380-480-208-240/dp/B01GVT1YYO I’ve U V W terminals, hows that work with single phase Live, Neutral and Earth?
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Nov 6, 2019 20:43
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Rapulum_Dei posted:Metal melters/chip eaters/clangers I don't see any manuals for that thing online. Does it have a diagram under the cover plate maybe? It's going to be live/live/earth, no neutral (assuming we're talking US split phase 240v - and not necessarily in that order - I have no idea which terminal should go to what).
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Nov 6, 2019 20:59
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Rapulum_Dei posted:Metal melters/chip eaters/clangers   You've got a dual voltage three phase motor.
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Nov 6, 2019 21:26
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Nice googling Yooper.
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Nov 6, 2019 21:34
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Huh. 240v 3 phase. Didn’t realise that was a thing.
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Nov 6, 2019 22:13
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Rapulum_Dei posted:Huh. 240v 3 phase. Didn’t realise that was a thing. Probably a question for the wiring thread but since it came up: What is the advantage of high voltage 3 phase? Lower amperage so you can run smaller wires which are cheaper than big wires?
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Nov 6, 2019 22:18
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Kaiser Schnitzel posted:It’s what my whole shop runs on! We've got a couple of weirdo machines that run 240/3. Some British OD grinders, a West German surface grinder, and a honing machine. Lower amps for the same power, which on a 1/2 hp doesn't mean much but with a 200 hp motor it becomes a huge issue. Transformers, bus bars, fusing, wiring, contactors/vfd's, everything becomes more expensive with the higher amperage.
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Nov 6, 2019 22:54
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Rapulum_Dei posted:Huh. 240v 3 phase. Didn’t realise that was a thing. yeah, my shop has this. For most old machines(bridgeports, lathes, jig bore, surface grinders) it doesn't matter, but newer machines (EDM, CNC) need transformers
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Nov 6, 2019 22:59
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It’s lucky I overspecced the 3 phase inverter when I got it 
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Nov 6, 2019 23:04
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rump buttman posted:yeah, my shop has this. For most old machines(bridgeports, lathes, jig bore, surface grinders) it doesn't matter, but newer machines (EDM, CNC) need transformers Our shop runs this too, but all our machinery, even our brand new EDMs, run on it.
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Nov 7, 2019 00:44
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Rapulum_Dei posted:Huh. 240v 3 phase. Didn’t realise that was a thing. A lot of bigger mine sites run everything on 3 phase (speaking from Australia) because then they only need one plug type. And most motor manufacturers often do them with 3 phase or single phase as a factory option. I've actually got an out of service SEW motor from a pump we serviced recently, 2.2kW which would run on single phase no issue at all in Australia. I've now gotta find a single to 3 phase VFD to run it with the 84 Engineering belt grinder kit I'm eventually going to get (eventually being key, it's a space issue right now)
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Nov 7, 2019 00:46
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Place I work has a ton of italian-made bore grinders that all require 3~ 400VAC 50hz and every time I'm reminded of it I go  all over again
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Nov 7, 2019 00:50
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