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So I'm buying a lathe of a dealer and they're happy to perform accuracy checks. Is there anything I should request? The machine already lists "Spindle nose accuracy 0.009mm" and "3 Jaw chuck running accuracy 0.04mm". I'd like to also specify that the tailstock is in line with the centre of the chuck (seems sensible? - I've seen a youtube video where it isnt on others by the manufacturer, Optimum) . Is there anything else I should request? Thanks. e: How should I specify that the spindle is true to the bed? within .000x per y? Not sure what is reasonable for x,y. Mudfly fucked around with this message at 17:38 on Jun 22, 2017 |
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Jun 22, 2017 14:37
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| # ? May 25, 2024 17:46 |
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Brekelefuw posted:I love my sherline machines. I have two lathes and a mill, and they are perfect for 90% of the work I do. How aggressive a DOC/feed can you manage turning mild steel, outta curiosity? e: mostly unrelated: ive been thinking about tackling a better steam engine than my lovely all-steel/aluminum wobbler I had to turn out for a class in the spring, but it feels kinda futile if I don't have a compressor handy to gently caress around with it. But lookie-look, the Deans Photographica guy comes to the rescue with the cutest drat steam plant + engine you've ever seen https://www.youtube.com/watch?v=ZBeCX1ZoWhU Ambrose Burnside fucked around with this message at 21:57 on Jun 22, 2017 |
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Jun 22, 2017 21:51
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Ambrose Burnside posted:How aggressive a DOC/feed can you manage turning mild steel, outta curiosity? I wouldn't feel uncomfortable taking 10-25 thou in a pass, maybe more depending on what the workpiece is and the cutting bit I'm Using. People cut some pretty crazy things on Sherlines. Super hard steels etc. And they have ceramic bits for that junk. I just use insert tools or HSS depending on what I need to do. The feed I couldn't tell you, because its cranking by hand maybe .100"/sec on average.
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Jun 23, 2017 00:04
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That's not too bad, I would have expected less given the Sherline's size. Unrelated- If a Canadian feller needed a matching worm and worm gear, where would he go? Gonna buy some stock for a couple projects all at once, and I'll grab the stuff for a mini rotary table if I know how much the appropriate gears will run me (cause I doubt I'd be up to making the things myself, even given CNC lathe access)
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Jun 25, 2017 03:01
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Crosspost from AI: Abrasive Flow Machining https://m.imgur.com/gallery/a4ThJ
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Jun 25, 2017 18:12
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AKA Morning After machining.
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Jun 25, 2017 20:39
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shame on an IGA posted:Crosspost from AI: Abrasive Flow Machining I need to figure out a home shop version of this!
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Jun 25, 2017 21:23
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Brekelefuw posted:I need to figure out a home shop version of this! I'm kinda scribbling back-of-envelope ideas too. Sorta thinking pressure washer, thickwall steel tube full of silly putty/abrasive, and a simple dividing piston.
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Jun 26, 2017 17:50
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Yep. I'm wondering if I can thicken my lapping compound slightly and force enough in to my tubes to polish them without distorting the thin brass walls.
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Jun 26, 2017 19:39
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I'd imagine you could achieve something similar (if more subject to uneven polishing from flow weirdness) with a thinner abrasive slurry you circulate through the tubing at lower pressure for a longer period of time.
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Jun 26, 2017 20:39
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Sure, that's how rock tumblers work. It'll just be slow as balls and hell on your fluid pump.
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Jun 26, 2017 21:49
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Holy poo poo it is literally silly putty http://www.flowgrinding.com/products-services/abrasive-media-system/ "The media base itself consists of a highly elastic borosiloxane polymer blended with oil-based lubricants to increase flowability. A carrier with a high percentage of polymer will be stiff and can be used to polish or radius large features; a carrier with a high percentage of lubricant will be soft and flow easily through small or long passages."
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Jun 27, 2017 01:40
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mekilljoydammit posted:I'm kinda scribbling back-of-envelope ideas too. Sorta thinking pressure washer, thickwall steel tube full of silly putty/abrasive, and a simple dividing piston. Get two old hydraulic cylinders, mount the rods together, fill one with this goop, and push it with the other.
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Jun 27, 2017 14:22
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One Legged Ninja posted:Get two old hydraulic cylinders, mount the rods together, fill one with this goop, and push it with the other. Sorta the same thing I was going for, except I was thinking of doing it in a way that noting of any real value gets lost as stuff wears out.
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Jun 27, 2017 14:25
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Eh. If you're patient enough, the cylinders won't be worth anything when you get them. 
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Jun 27, 2017 19:49
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Shovel chat: The shovel on the left was fabricated in late April. It started off ok, but after a few days of extremely moderate shovelling the tip blunted and it doesn't shovel as well.    I could sharpen it, but I don't want to add "shovel sharpening" to my daily to-do list. My regular old trench spade is better. It draws sparks when I hit rocks with it and it hasn't worn out. The material is thinner and more rock-resistant. Is it a different alloy or heat treating or what? DreadLlama fucked around with this message at 17:44 on Jun 28, 2017 |
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Jun 28, 2017 07:58
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DreadLlama posted:Shovel chat: Probably a different alloy, what did you make your shovel out of? If it's something like 1018 its not going to hold up.
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Jun 28, 2017 10:56
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The blade is made from some metal I found on the ground. It is not likely to be anything special. What ought I have used?
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Jun 28, 2017 17:43
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Considering the amount of impacts vs rocks, case hardening and temper would probably be the way to go, maybe 5120 or O6. Stuff they make gears out of.
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Jun 28, 2017 20:54
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DreadLlama posted:Shovel chat: If you're hitting enough rocks to dull a shovel that quickly, I'd recommend a pick instead. Maybe get a pick mattock, the blade end is good for tree roots.
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Jun 28, 2017 21:04
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DreadLlama posted:The blade is made from some metal I found on the ground. It is not likely to be anything special. What ought I have used? Your mystery metal may or may not be a carbon ("tool") steel. Probably not. If it is just random sheet metal, it is probably "mild" steel, which is just iron with some small amounts of impurities and no more than ~0.25% carbon. Mild steel is useful as a structural material; it is tough and malleable, but not hard and will not hold an edge. You cannot effectively harden mild steel solely through quenching/tempering. "Case hardening" is a process that adds a thin hard layer to the outside of a core of softer, tougher metal. Typically it involves either hardening the surface of a body of tool steel, or, adding more carbon & hardening the surface of a low-carbon/mild steel. Carbon steel has somewhere between ~.25% and a little over 2% carbon content. These steels can be hardened through simple quenching/tempering processes; typically heating the steel to a glowing-red, non-magnetic ("austenitic") temperature and then rapidly cooling through quenching to freeze the steel into a small-grained structure. Tempering involves re-heating at much lower temperatures of just a few hundred degrees, to refine the exact hardness of the metal. Sometimes an object has different heat treatment to different parts; for example, you can make the edge of a blade very hard while leaving the spine of the blade softer/tougher. There are a huge variety of steels with additional alloying elements, such as chrome and molybdenum ("chromoly" steel has both), nickel, vanadium, and so on. Thousands of specific alloys for thousands of specific applications. Some of them have strange hardening properties, such as "air-hardening" steel which essentially "quenches" in air (these can be notoriously difficult to work outside of a factory). Even among just normal carbon steel, there are differences in manufacture (cold vs. hot rolled, for example) that affect the material properties. Manufactured tools tend to use combinations of steel alloys designed for the job at hand, and heat treated to achieve very specific qualities. Hardness goes hand in hand with brittleness, while toughness goes hand in hand with softness. Spring steel can be bent to some degree over and over without breaking down: other steels experience microscopic damage with every bend, locally hardening which soon results in cracking and breakage. Tools may be forged or stamped from sheet metal or some combination of both. Case-hardening, differential quenching, it goes on and on. For the home tool maker, it behooves you to use the right steel for the job. For jobs where hardness is important, you need to use a steel that can be hardened, and then follow reasonably controlled hardening processes. Your shovel blade is no exception. It's probably fine for digging in soil; you can use random who-knows metal to make a snow shovel or a gardening spade. But for any work that involves hitting rocks and retaining an edge... well, you need to learn up on how to anneal, shape/forge, quench, and temper carbon steel. There's lots of folks in this thread that can help. But you may find it's all not worth the effort, when you can buy a manufactured garden shovel with a hard edge for like $20. Leperflesh fucked around with this message at 22:21 on Jun 28, 2017 |
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Jun 28, 2017 22:16
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DreadLlama posted:The blade is made from some metal I found on the ground. It is not likely to be anything special. What ought I have used? The right tool for the job  But seriously alloy chat about a straight/flat, pointed shovel is a moot point. Alloys don't matter when the design is bad. All shovels I can think of are thin and radiused or V folded.
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Jun 28, 2017 22:22
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More of a turf cutter, maybe? The flatness makes it more likely to bend and less useful for scooping stuff up, but he didn't mention either of those as problems for his application so 
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Jun 28, 2017 22:42
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FWIW, plate and especially sheet steel alloys are likely to be even softer and less durable than the generic "mild steel" suggests- as they're the main modern candidates for bending and other coldworking fabrication (alongside wire), they usually have less carbon than other dimensional stocks will, and may even be annealed as a finishing process at the rolling mill. ...in other words, you probably picked the single worst possible steel candidate for that job, lol. You want something heat-treatable that is then tempered appropriately for the task. It isn't worth putting time and sweat and blood into tools if you cheap out on materials when it counts, it just wastes your time once those tools fail prematurely. e: Leperflesh posted:More of a turf cutter, maybe? The flatness makes it more likely to bend and less useful for scooping stuff up, but he didn't mention either of those as problems for his application so given how soft the blade probably is, if he were trying to lever stuff with it shovel-style I'd assume there'd already be a bend or two in it with a perfectly flat plate metal blade and there doesn't seem to be, so yeah i assume it's designed that way for a particular purpose Ambrose Burnside fucked around with this message at 23:20 on Jun 28, 2017 |
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Jun 28, 2017 22:57
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Anyone recommend a good resource for learning nc programming? I got thrown in the deep end at work and I'm really feeling my lack of knowledge in this area. Local community college offers CNC courses and I'm considering that but they'll probably want me to start at the beginning of their machining classes and work up. Any books you would recommend for teaching yourself?
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Jun 29, 2017 00:36
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honda whisperer posted:Anyone recommend a good resource for learning nc programming? I got thrown in the deep end at work and I'm really feeling my lack of knowledge in this area. What are you hoping to learn with regard to CNCing at the local college? Talk to the instructor at the CC and see if youre right about that. I did machining at a tech school and there was an experienced manual guy who came through, proved he knew his poo poo on a mill and lathe, and went to CNC machining pretty quick. For teaching yourself, I'd take whatever cam software you use and work tutorials. If there are video tutorials online, start there but then move on to the actual examples that come with every CAD/CAM suite. I learned MasterCAM this way and became pretty proficient. Could also go to the local tech shop and use their machines.
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Jun 29, 2017 00:54
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honda whisperer posted:Anyone recommend a good resource for learning nc programming? I got thrown in the deep end at work and I'm really feeling my lack of knowledge in this area. Check their catalogue and see. It'll tell you if they have prerequisites for the classes you want. There's also usually a one year program for a CNC programming certificate, so you could also look at getting one of those to have something to show for your schooling. What are you running? Mills? Lathes? And what brand of machine?
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Jun 29, 2017 01:03
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honda whisperer posted:Anyone recommend a good resource for learning nc programming? I got thrown in the deep end at work and I'm really feeling my lack of knowledge in this area. I bought Smid's book as a reference. We did some factory training for our Haas and it covered drat near anything we needed to know about the lathe. I looked into my CC, when they had a machine tool program, and was fairly disappointed in how shallow it was. Personally I like sticking toolpaths into Fusion360 and using that as a test bed for complexer stuff.
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Jun 29, 2017 01:35
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Speaking of CAM, how do I generate a toolpath for the spiraly ramp feature using fusion360? I've tried trace, pencil, and scallop but I'm not getting the desired results.
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Jun 29, 2017 02:03
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rawrr posted:Speaking of CAM, how do I generate a toolpath for the spiraly ramp feature using fusion360? I've tried trace, pencil, and scallop but I'm not getting the desired results. Fusion360 CAM is the same as HSMWorks, which is what I use, and I would probably do that with a parallel finishing operation. It'll take a while but it'll get close. What size/profile of tool are you using and what material is this? That's a part that can only be approximated with a 3-axis machine, so it's going to be a decision between various tradeoffs.
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Jun 29, 2017 02:14
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Hurco vmx42i with edgecam for the nc side. Did the tutorials that were included, took a three day training course, started using high efficiency milling on anything that wasn't a rectangle with holes in it. God I love it. They bought a rotary table for my machine. Trying to edit the post to get it working has me ripping my hair out. I know what it can do and what I want it to do but trying to make them both friends shows me I'm lacking in understanding of what's going on behind the scenes. I've got the simulation looking good in edgecam (simple test program) but when I draw it on the hurco it goes to hell. Classes and tutorials covered the software but the post and documentation are severely lacking.
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Jun 29, 2017 02:20
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Sagebrush posted:Fusion360 CAM is the same as HSMWorks, which is what I use, and I would probably do that with a parallel finishing operation. It'll take a while but it'll get close. It's brass, and in my untrained/inexperienced mind I'm thinking of a flat bottomed endmill that moves in a circular path with decreasing Z to cut the ramp in one pass - it's okay if it leaves a bit of a fillet against the sidewall from the circular footprint of the tool.
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Jun 29, 2017 02:39
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DreadLlama posted:Shovel chat: Buy a high quality commercially made shovel close to the shape you want, cut the handle and socket off, and weld it onto your custom handle. Unless it has to be flat, that is... iForge fucked around with this message at 03:43 on Jun 29, 2017 |
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Jun 29, 2017 03:37
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You can't realistically cut that in a single pass because you'll be plunging deeper and deeper into the part while slotting, and that's a great way to break the tool. You could approximate the shape by roughing the area out using whatever strategies you want (adaptive clearing, pocketing, etc), leaving like .010 remaining, and then doing an ascending spiral finishing cut by contouring the inner edge. However, that's still not going to be perfect, because the bottom of the end mill is a flat circle, and it's not parallel to the plane that you're trying to cut. The end result is that you'll get a shape with a concave surface:   If that works then go for it. Don't do a descending cut (as shown here) because then you'll be dragging the tool along the surface while the cutting edges spin in the air. Start at the bottom and climb upwards. You can get a closer approximation by going back and forth with a small tool, doing parallel finishing. It will give a stair-stepped effect, but with fine enough stepover it may be suitable for what you're making. The only way to achieve that shape perfectly is to incline the head relative to the part, so the tool is perpendicular to the intended surface.
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Jun 29, 2017 03:37
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Can you fixture it at the angle the spiral is on so that cut will be parallel to the tool path?
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Jun 29, 2017 03:42
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Thanks for going through the trouble of modeling it up. What you illustrated was what I had in mind; I'll give it a shot. You're right that parallel finishing might work better. I'll try both out tomorrow.  fake edit: Come to think of it, since my Taig is a tilt head (never thought this would come in handy), I should be able to do what you've described and machine it without any Z movement. e: Volkerball posted:Can you fixture it at the angle the spiral is on so that cut will be parallel to the tool path? This was the first thing I thought of, but I couldn't think of a good way to actually do it until just now. If/when I need to make multiples, I'm thinking that I can mill the silhouette of the part at the ramp angle into soft jaws. That'll save me from having to retram the head between different setups. rawrr fucked around with this message at 04:03 on Jun 29, 2017 |
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Jun 29, 2017 03:46
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Is it a flat angle? If so you could throw it on a sine plate and just profile. Unless I misunderstand a tilt head would still have to move in z but would have the same effect as kicking the part onto the angle of the ramp.
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Jun 29, 2017 03:59
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Yep, you can certainly do it if you can angle the head. Zeroing the machine while the head is angled, and properly accounting for the trigonometric error that that creates in your toolpaths, is left as an exercise for the reader :P
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Jun 29, 2017 04:00
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Oh man, you're right - zeroing this doesn't sound fun. Seems like it'd be faster to just do the parallel passes unless I'm making a bunch of these. 
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Jun 29, 2017 04:13
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DreadLlama posted:Hello and please allow me to introduce you to my glorious shovel. I'd stick it in the ground and jump until the footrest was in the ground; used the other shovel for prying. Ideally I'd have one shovel for both. CarForumPoster posted:The right tool for the job V-folding it up the back seems like a very good idea. If I were building it again the pointy end would be two separate pieces meeting at an angle. I've already got space on the heel plate. Leperflesh posted:excellent advice This will hopefully be have been my first of many metal objects. It is a good skill to develop in my opinion. For example: shame on an IGA posted:Considering the amount of impacts vs rocks, case hardening and temper would probably be the way to go, maybe 5120 or O6. Stuff they make gears out of. This is probably technically correct. But I think it would be a mistake if I were to order a sheet of steel off the internet right now. Annealing and tempering are part of a multi-step process requiring temperature control. I think I should build a forge?
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