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I get the MIOSHA (Michigan Osha) email alert whenever someone dies in a workplace related accident. Almost always it's a matter of either lockout-tag out, don't stand under the load, or wear a safety harness. Ladders, scaffolding, and powered equipment (forklift etc.) seem to be the main culprits. Metalworking is usually doing something with a forklift, standing under something heavy, or someone crawling inside of an injection mold/mill/lathe and it turns on  We hired a guy who only had one arm and lost it at a shipyard in town. They had a 40ft long shear, the guy on the other end cycled the machine while he was reaching into it for something. Instead of going "we should make this safer", they accused him of being an unsafe worker. I know it's terrible but we referred to him as the one armed bandit, he was really a great guy to work with and ran a machine tool faster with one arm than most people could with two. I've got a pretty good relationship with the MIOSHA guys, we invite them in yearly, they give us an honest review, we fix what we find, and have zero reportable injuries in 3 years.
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Mar 20, 2023 16:06
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I haven't seen truly stupid stuff at my job yet, but I'm typically the person telling others to do things safely. When someone is deburring stock at the belt sander for half an hour without wearing safety gloves or some form of mask. Or when someone crawls into a machine to fix something without turning it off, or at least in emergency stop. Or when the machine is working and the doors are open, and they're not at least wearing safety goggles. Or when they're loving around with the forklift. I just wish they would listen sometimes.
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Mar 20, 2023 17:50
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Kaiser Schnitzel posted:I remember in college having to make a 15’ tall atom bomb that someone had to be able to sit on, had to be moveable by two people but couldn’t have wheels, had to be built in like 3 days, with budget of like $5. I asked a professor what the ‘right way’ to do that was and he said basically ‘well, probably nobody has ever had to make this exact thing before so there isn’t a ‘right way,’ you’ve just got to make one up.’ Don't leave us hanging. How did you do it?
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Mar 20, 2023 18:06
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Idk if there was a watershed moment or just a critical mass of people who've had injuries prevented by ppe so it's more common to have mentors and coworkers who can tell you to wear PPE X as it saved their eye/hand etc. Also PPE has gotten less intrusive and more comfortable so wearing a respirator for 8h under a wedding mask isn't as terrible as it used to be. I also think better technology has made it easier to use tools in a safe manner - we got a new mill at work and between a 3d taster and one of those spinning windows there's zero reason to have the door open and the spindle turning more than 5-10rpm so we never felt the need to defeat the door safety vs old machines where the only way to get a good view sometimes is to run with the door half open. I think it's just lots of little things stacking up that have led to a culture shift vs any big moment.
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Mar 20, 2023 18:11
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Skunkduster posted:Don't leave us hanging. How did you do it?
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Mar 20, 2023 18:26
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meowmeowmeowmeow posted:
I've started using $35 gun range headphones and holy poo poo, talk about amazing. You can still hear the machine, the guy on the forklift behind you, someone yelling, but it automatically keeps everything at a safe level. Compared to the crunchy ear plugs (right, so roll this yellow foam between your grimy rear end machinists fingers...) or the old fashioned muffs, these things are like magic.
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Mar 20, 2023 18:30
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meowmeowmeowmeow posted:Idk if there was a watershed moment or just a critical mass of people who've had injuries prevented by ppe so it's more common to have mentors and coworkers who can tell you to wear PPE X as it saved their eye/hand etc. Liability insurance companies started pushing PPE heavily in late 90s as I recall. Like, it was baked into your policy what you had to provide, train on, and require use of for your employees or risk getting dropped. All the rest of the above happened after that, largely because of that.
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Mar 20, 2023 18:42
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Karia posted:If you decide to keep your homebuilt one, consider adding a stiff spring of some kind under the head of the bolt you're using to adjust the friction (maybe a belleville washer or wave disk spring).
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Mar 22, 2023 00:56
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Yooper posted:I've started using $35 gun range headphones and holy poo poo, talk about amazing. You can still hear the machine, the guy on the forklift behind you, someone yelling, but it automatically keeps everything at a safe level. Compared to the crunchy ear plugs (right, so roll this yellow foam between your grimy rear end machinists fingers...) or the old fashioned muffs, these things are like magic. I have a 5hp dust collector, a planer, a compressor, and so on. Would your headphones block that poo poo so I can still communicate? It’s super annoying, it’s basically “audio off” mode when I have to run any of that stuff, so I find myself trying to minimize that time. It’d be cool to just slam the big DC on when I walk into the shop and not worry about it, rather than spinning it up and down per job.
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Mar 22, 2023 19:18
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Bad Munki posted:I have a 5hp dust collector, a planer, a compressor, and so on. Would your headphones block that poo poo so I can still communicate? It’s super annoying, it’s basically “audio off” mode when I have to run any of that stuff, so I find myself trying to minimize that time. It’d be cool to just slam the big DC on when I walk into the shop and not worry about it, rather than spinning it up and down per job. Let me test it. Normally I'm working solo so I'm not sure how it'd handle a continuous noise and conversation at the same time. I'll tag along for compressor room PM's and that'll be a perfect time to test it out.
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Mar 22, 2023 20:24
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Anybody else watching the Mandalorian? The Armorer is holding her hammer too far up the handle, her form is all wrong, and her anvil is too tall for her. Further more she keeps saying 'forge' when she is actually casting. Also steel is red hot when molten. I sure hope somebody gets fired for that blunder. I do appreciate that she fights with a hammer and tongs treats them with reverence.
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Mar 24, 2023 00:40
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yes, and she's forging and working with "beskar" which is unobtanium, not really steel, so that excuses some of what's going on. But also yes her forging technique is bad. It makes zero sense that the metal that stops blaster shots and light sabers is also easily forgeable at a red heat though.
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Mar 24, 2023 00:48
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deoju posted:Also steel is red hot when molten. I haven’t gotten to watch the latest episode yet but I think I can say with authority: what steel, that’s beskar, ffs, and you want to talk about blunders Leperflesh posted:It makes zero sense that the metal that stops blaster shots and light sabers is also easily forgeable at a red heat though. It’s a magic space flame
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Mar 24, 2023 00:50
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Also if she is going to wear gloves they should be very tight or tucked into her sleeves to prevent anything hot falling into them and burning her. 
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Mar 24, 2023 01:20
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deoju posted:Also if she is going to wear gloves they should be very tight or tucked into her sleeves to prevent anything hot falling into them and burning her. this is the way
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Mar 24, 2023 01:23
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Its been a while since I've had a welding question, but here goes. A while back someone mentioned that when you're stick welding, and you have AC/DC rods, you should really only use them on AC if your welder is AC only. Is there a specific reason for that? How does that affect a weld? If AC welding is less good, why are there even AC only welders and/or why are there not just DC welders? It seems like wall power can easily enough be converted to DC that that wouldn't be an issue. Are there DC only welders?
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Mar 24, 2023 01:27
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wesleywillis posted:Its been a while since I've had a welding question, but here goes. Afaik the only issue with stick welding and your current type is that the flux is generally optimized for AC or DC only so your rod will work best on one of them. The main functional differences are potential weld defect increases (subtle but important for code work), puddle instability, and arc instability especially when using DC rods on AC current. AC welders are simply cheaper to make requiring only a transformer and no rectifier but I think the difference is marginal these days. Also the Miller Maxstar and Lincoln Invertec only do DC stick and DC tig.
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Mar 24, 2023 02:01
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wesleywillis posted:Its been a while since I've had a welding question, but here goes. AC only welders were cheaper. You don't need a rectifier on the output of the transformer. This is true for old school transformer based machines like the tombstone style or the 500lb giant boxes from years past. You can pick up a transformer based AC stick welder for cheap assuming you can move it. With modern power electronics it is cheaper to rectify the mains and use a high frequency switching power supply to create a constant current (tig/stick) or constant voltage (mig). These machines do DC by default and getting them to do AC costs more as you need a more complex power stage. The only reason I am aware of to use AC stick is if you are dealing with magnetic parts. Or you are welding enough on your work it would magnetize if welding DC (arc blow). This can be minimized with welding technique (alternating weld direction, changing grounding locations). The college I took welding courses at had DC only stick machines and the instructor said that the only reason to use AC was if that was all you had. AC welding is also loud as gently caress and the nice frying bacon sound of DC is so much better.
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Mar 24, 2023 02:18
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wesleywillis posted:Its been a while since I've had a welding question, but here goes. AC is technologically easier to accomplish. Most welders here look on AC stick welding like something to be avoided since you could get a DC rectified welder since the 1980s. AC stick is known for making welds that get brittle as they get cold which has been a big deal here, a lot of industrial welding would've been stuff like making ice breakers for instance. Also brittle welds are why some people I know avoid 6013s like the plague and only use it if they have to, even though they are DC sticks (might be AC compatible iirc). His Divine Shadow fucked around with this message at 08:34 on Mar 24, 2023 |
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Mar 24, 2023 08:32
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Huh. Now what do I do? (answer: I order some cutting tools, because it didn't come with any and I had no idea what size the tool post would hold)
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Mar 24, 2023 16:20
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goons posted:Thanks for the explanations. Are the typical (6010, 6011, 6013, 7018 etc) rods, when used with DC able to be used both + and -? Fake edit: Never mind, thats what the last fuckin digit is for.  I always forget which is which (speaking of that) is DC + "reverse polarity"? Or DC -?
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Mar 25, 2023 15:00
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wesleywillis posted:Thanks for the explanations. Are the typical (6010, 6011, 6013, 7018 etc) rods, when used with DC able to be used both + and -? Almost every DC rod will be DCEP which is DC Electrode Positive. I.e. the positive output on the welder goes to the welding rod. Some rods specify DCEN as well. DCEP = more penetration, DCEN = less penetration. DCEP = normal, DCEN = reverse. I pretty much only use DCEP and just turn down the current a bit if I need a cooler weld. Modern welders with infinitely adjustable and repeatable current make this practical. I would try DCEN if I had a poor fit up and was trying to close a gap (as long as the rod supports it). The box the rod comes in will specify the recommended current and electrode polarity.
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Mar 26, 2023 00:25
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I haven't seen this in any american video I've seen on welding, but maybe I've missed it. But my stick welder has a remote, basically a handle with a thumb wheel so you can fine adjust the amperage when welding. This isn't uncommon here for stick welders. Here's a video where the remote is used and talked about : https://www.youtube.com/watch?v=eXv_TPraJkk I gotta admit mine has been laying in a drawer most of the time.
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Mar 26, 2023 08:38
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I made this part, it has a thread in the middle. It's a plunger or piston for a high pressure washer. I am wondering if I need to weld it or if I can trust loctite enough to hold it? You should be able to see that the top of the plunger is a separate part (stainless) with a threaded thu-hole, this holds the entire part together really. I could tig weld the stainless rod to the lid part but I am fearful of it distorting, the lid needs to seal tight so there won't be leaks.
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Mar 29, 2023 11:10
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Loctite would probably work. What about just a couple tack welds? Will you need to take it apart at some point?
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Mar 29, 2023 12:24
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I will probably take it apart to see how the repair holds up. I like the idea of loctite since it also seals the thread. Tacks might work if I can keep it from being too hot for the loctite. Or I should just weld it, then finish turning it. The other end of the screw is just gonna be held with loctite too. I can't weld both sides.
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Mar 29, 2023 13:05
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I'm maintaining a bunch of well-used 5-axis dental mills that all produce parts with some degree of gouged toolpath along the parting line (the equator-like boundary for the b-axis 'flip'), frequent offset errors on either side of the part (the two flipped sides don't perfectly line up), and bad surface finish on one side of the part (probably from the rotational offset issue causing one side to have a crazy DoC for the 0.3mm tools we finish with) and I'm supposed to "fix it" and. man. I do not have the foundational experience for this. most of my milling experience is on a bridgeport knee mill, not a very lightweight but precise 5-axis cnc job with a closed ecosystem and opaque control/calibration. most of the setup stuff I learned doesn't transfer over at all. i got a tool&die guy who jumped to dental stuff to take a look at our parts and he suggested our rotary axes need replacement, and/or the leadscrews have too much backlash. the rotaries are a nightmare to replace and $3500 a pop, so here's hoping it's the leadscrews. i took one of them apart and the x-axis leadscrew i checked out has significant backlash compared to a brand-new leadscrew, so that's as good a place to start as any. how hard can it be to replace 3 leadscrews on... 7 mills... oh yeah, the dental CAM software is also totally opaque and doesn't let you adjust your milling strategies, so that may or may not be contributing to the problem. other than that, you know, dental milling is cool. zirconia is an extremely interesting material to mill, you machine it in a soft 'green' state and then sinter it into an extremely hard material, lets you run parts very fast and with reasonable tool lifespan. it also shrinks when you sinter it, so you can cheat some extra fine detail out of your parts. CoCr alloy sucks rear end, I want to run some titanium but it hasn't come up yet. Ambrose Burnside fucked around with this message at 03:12 on Mar 30, 2023 |
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Mar 30, 2023 03:08
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Ambrose Burnside posted:I'm maintaining a bunch of well-used 5-axis dental mills that all produce parts with some degree of gouged toolpath along the parting line (the equator-like boundary for the b-axis 'flip'), frequent offset errors on either side of the part (the two flipped sides don't perfectly line up), and bad surface finish on one side of the part (probably from the rotational offset issue causing one side to have a crazy DoC for the 0.3mm tools we finish with) and I'm supposed to "fix it" and. man. I do not have the foundational experience for this. most of my milling experience is on a bridgeport knee mill, not a very lightweight but precise 5-axis cnc job with a closed ecosystem and opaque control/calibration. most of the setup stuff I learned doesn't transfer over at all. i got a tool&die guy who jumped to dental stuff to take a look at our parts and he suggested our rotary axes need replacement, and/or the leadscrews have too much backlash. the rotaries are a nightmare to replace and $3500 a pop, so here's hoping it's the leadscrews. $3500 parts are on the cheap side for CNC parts and practically free for medical devices
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Mar 30, 2023 11:25
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Yeah I was going to say. The rotary axis we have for our shop bots is like a $15,000 thing and those tools just make dumb little wooden toys, not teeth
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Mar 30, 2023 15:25
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Cool, I found a hobby more expensive than airplane racing
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Mar 30, 2023 15:49
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Ambrose Burnside posted:I'm maintaining a bunch of well-used 5-axis dental mills that all produce parts with some degree of gouged toolpath along the parting line (the equator-like boundary for the b-axis 'flip'), frequent offset errors on either side of the part (the two flipped sides don't perfectly line up), and bad surface finish on one side of the part (probably from the rotational offset issue causing one side to have a crazy DoC for the 0.3mm tools we finish with) and I'm supposed to "fix it" and. man. I do not have the foundational experience for this. most of my milling experience is on a bridgeport knee mill, not a very lightweight but precise 5-axis cnc job with a closed ecosystem and opaque control/calibration. most of the setup stuff I learned doesn't transfer over at all. i got a tool&die guy who jumped to dental stuff to take a look at our parts and he suggested our rotary axes need replacement, and/or the leadscrews have too much backlash. the rotaries are a nightmare to replace and $3500 a pop, so here's hoping it's the leadscrews. In theory a probe would be a good solution, but I'm assuming that isn't an option. If you have a problem with people making offsets on one index without making corresponding offsets on different indexes to keep the relationship between features together, you could probably whip something together using macro programming. We do something similar on a 4 axis machine. The guy running the machine only needs to edit G54, which is the B0 index where the top of the part is facing the spindle. Then in the program, it calculates the rise and run from G54 to the center of rotation, and saves G55, G56 etc for all the other indexes. Then if someone moved the Z up on the B0 index, the program would offset the B90 index positive in X, and the B-90 index negative in X, etc, so that the relationship from the center of rotation for all indexes stays the same. If the machines are cutting lovely and dimensions are bouncing all over the place, then this won't save you obviously. You could try to make sure you're using conventional milling everywhere to help with backlash but if the machines are failing then the machines are failing.
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Mar 30, 2023 16:30
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Ambrose Burnside posted:I'm maintaining a bunch of well-used 5-axis dental mills that all produce parts with some degree of gouged toolpath along the parting line (the equator-like boundary for the b-axis 'flip'), frequent offset errors on either side of the part (the two flipped sides don't perfectly line up), and bad surface finish on one side of the part (probably from the rotational offset issue causing one side to have a crazy DoC for the 0.3mm tools we finish with) and I'm supposed to "fix it" and. man. I do not have the foundational experience for this. most of my milling experience is on a bridgeport knee mill, not a very lightweight but precise 5-axis cnc job with a closed ecosystem and opaque control/calibration. most of the setup stuff I learned doesn't transfer over at all. i got a tool&die guy who jumped to dental stuff to take a look at our parts and he suggested our rotary axes need replacement, and/or the leadscrews have too much backlash. the rotaries are a nightmare to replace and $3500 a pop, so here's hoping it's the leadscrews. Are these the Roland Mills? Those things are basically 100% wear parts and should be tossed once they start cutting weird if you're doing heavy production. I had the exact same job from 2012-2016. Our shop had 50 Arum 5-axis mills (from korea) for machining zirconia. We also did custom titanium abutments (on really nice Fanuc Robodrills). I was in charge of all the CAM automation and thankfully didn't have to maintain the machines much. Dental machining is a really neat area.
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Mar 30, 2023 17:59
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Sagebrush posted:Yeah I was going to say. The rotary axis we have for our shop bots is like a $15,000 thing and those tools just make dumb little wooden toys, not teeth we've spent that much to replace a 1024x768 HMI don't hire supervisors that will punch Siemens kit, was the main takeaway there
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Mar 30, 2023 18:54
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I have been working on a laser interferometer system to calibrate and setup machines in my shop. My first target is my old AMC 490 lathe. It has noticeable wear close to the headstock and it is bad enough I want to rebuild it. The first step is measure what I am working with: This confirms what I had measured previously but in much more detail. Some pictures of the setup: Looking at the tailstock end with the laser source on the tripod and the beam splitter and linear interferometer:  Towards the headstock showing the straightness prism and retroreflectors:  Close up of the 5axis adjuster on the straightness prism:  Close up of the optics on the tailstock. These are mounted on another 5axis adjuster: 
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Mar 31, 2023 04:55
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that is extra as poo poo but i love it i am pretty sure that lasers, let alone laser interferometry, didn't even exist when that lathe was cast. lol
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Mar 31, 2023 05:31
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Does anyone in these here forums have any experience with the arcdroid CNC plasma cutter? Bro and I have been contemplating getting some kind of CNC plasma for the shop, but space is at a premium so having a portable small unit that can work on part of a large sheet but doesn't have a huge footprint at all times seems really attractive. It's not a cheap tool though, so investing in one would be dumb if it's useless junk. I would expect it to be inherently less accurate than a normal gantry style CNC that's well built but I don't know much about these things, and super high precision isn't necessarily a primary concern for the use cases we have in mind.
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Mar 31, 2023 08:40
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Awesome stuff. Looks like a 3d printed flexure adjustor? I love it, getting those things aligned properly sucks. Might have to build one of those for the next time I have to shoot a machine.
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Apr 2, 2023 21:50
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Sagebrush posted:that is extra as poo poo but i love it The lathe was manufactured sometime in the late 1960s and the first optical laser was in 1960. So they are at least contemporary  Karia posted:Awesome stuff. Looks like a 3d printed flexure adjustor? I love it, getting those things aligned properly sucks. Might have to build one of those for the next time I have to shoot a machine. Yes, I will be uploading the files to printables or thingiverse so you can print your own. I designed them because getting everything in place was too finicky otherwise.
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Apr 3, 2023 00:40
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I am impressed at the depth of cut my lathe can make with the right insert. My lathe is a south bend 9 clone. This shows two cuts taken on a piece of hard chromed rod, using an WNMG insert for aluminum that is a lot sharper than the regular inserts. I got the whole rod down to length in four cuts total. Almost done with all four new pistons. 
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Apr 3, 2023 07:28
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stick that tap wrench in some evap-o-rust my man
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Apr 3, 2023 08:23
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