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Hadlock posted:Will you put these up for sale please on SA mart, I'll buy at least two Like if I fly cut a new skillet on the bottom you'd buy 2? What would you pay for one? I assume shipping will suck.
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Jan 18, 2023 03:02
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How flat will a cast skillet even stay if you fly cut it
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Jan 18, 2023 03:03
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Dance Officer posted:It's a good rule of thumb, but not always true. If you predrill an M2 roll tap with a 1.7mm drill like the rule says you should, it's going to cost you your tap. Yeah, as I mentioned, the ‘Major - Pitch’ formula is for cut threads only. For roll/formed threads, look it up in the Machinery Handbook or your tool supplier’s literature. On threads that small I usually just start the thread with the tap on the CNC and and the go to full depth by hand, but I’m a 100% prototype shop and rarely have to do more than 4 or 5 pieces of each part. If I was doing real production I’d be a lot more fancy about it. shame on an IGA posted:oh they are and it's about that time of year for them to flood our receiving department with unsolicited hardcover catalogs again I’m using a Hoffmann catalog as a spacer under one of my drum machines in my studio setup 😂 tylertfb fucked around with this message at 04:01 on Jan 18, 2023 |
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Jan 18, 2023 03:56
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honda whisperer posted:Like if I fly cut a new skillet on the bottom you'd buy 2? Yes. I want one, we vacation somewhere that has a glass stove top and I'm in charge of breakfast sausages and omelettes, my buddy wants one. I bet if you post something over in the GWS cast iron thread someone else will want one if the price is reasonable I think a new lodge 12" skillet is $30 and then whatever your time is worth to do an additional run of 2 on top of your 1. They are about 8lbs (per google, maybe less after milling) USPS says shipping is $12.95 Apparently the post office will accept durable unwrapped items for shipping (like coconuts), kind of curious if you slap a priority mail label on the freshly cut bottom, if they'd accept it for shipment
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Jan 18, 2023 16:00
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Hadlock posted:Yes. I want one, we vacation somewhere that has a glass stove top and I'm in charge of breakfast sausages and omelettes, my buddy wants one. I bet if you post something over in the GWS cast iron thread someone else will want one if the price is reasonable I'm gonna toss one of my pans on the surface grinder tomorrow. We've got a beautiful big West German unit that doesn't get used enough.
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Jan 18, 2023 18:07
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First welding/steel fabrication project in.... close to 25 years? Last project was building a gooseneck trailer adapter thing out of 3x3" angle iron using a stick welder, back in high school. Building a glorified go kart with a longer (64") wheelbase modeled after 1920 style car (like an old bugatti, but at 50% scale) out of some 3x1 16 ga (0.060) rectangular tubing for the ~96" frame rails. I need to do, I would guess 36-60 inches of welds and probably won't need it again for many years. Picked up the Titanium 125 (120v!) flux core welder, rather than shell out for a mig or tig setup with gas cylinder First attempt at welding. Did not clean the metal, pushed, rather than pulled, torch was 1.5" away from the work piece, total disaster:  Penetration looked ok on inspection though:  Found my wire brush, things improving with practice. Not great, but a servicable tack weld to start from:   Still need to box the bottom of the frame where I cut some out. I suspect a lot of grinding and re-welding is in my future, but feels good to be building something real with my hands for the first time in a long while.
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Jan 21, 2023 19:23
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Hadlock posted:
I don't know about mig/flux, but I'm pretty sure with stick you're supposed to push rather than pull because that will kinda like pre-heat the metal as you go along. I have to admit that I pull whether doing stick or flux myself, but I'm pretty sure its not "proper".
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Jan 21, 2023 20:16
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Hey speaking of welding, I want to fab up some step bar type devices fer muh TRUCK! I've got some brackets and was wondering if I need to worry about warping when I weld. Bracket is 4 inches wide, 1/4" thick. I was planning on getting some 1.5" x 3" rectangular box steel either 1/8" or 3/16" wall and weld it on as shown by the red rectangle in the pic. Placed a bit more squarely obviously. I was just wondering though if doing that would cause the bracket to warp in the manner that the yellow line is depicting.  Its probably not a big deal to clamp these to something before welding if that will help. I think I've got a few big pieces of square box laying around work I can clamp them to. What does anyone suggest for welding? I was figuring I'd tack weld opposite corners, and then............................. ? Should I weld the long edges first? Short edges? should I try and run a continuous bead all the way around?
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Jan 21, 2023 20:36
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wesleywillis posted:I don't know about mig/flux, but I'm pretty sure with stick you're supposed to push rather than pull because that will kinda like pre-heat the metal as you go along. No. I was taught "when there's slag, you drag". The reason for this has to do with controlling the flux coverage of the puddle. If you try to push, the flux will also go in front of the weld and lead to badness (flux under/in the weld). You can push GMAW/TIG but not flux core or stick. wesleywillis posted:Hey speaking of welding, I want to fab up some step bar type devices fer muh TRUCK! How much load is on the section you are welding on? Will a partial weld be acceptable? Welding the short ends will warp the bracket less than welding the long axis. If it will be strong enough then just welding the short axis will most likely not warp the base metal by enough to matter. If you need to weld the long axis the base metal will warp. Clamping it down will minimize this but it will still happen. Welding short sections and letting the part cool between welds will also help. The base metal is only 1/4" though so you can flatten it out again with a hammer without too much trouble. I usually just clamp stuff like this down to my welding table as well as I can. Weld it. And then use a combination of hammer, vise, and hydraulic press.
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Jan 22, 2023 05:55
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ZincBoy posted:No. I was taught "when there's slag, you drag". The reason for this has to do with controlling the flux coverage of the puddle. If you try to push, the flux will also go in front of the weld and lead to badness (flux under/in the weld). You can push GMAW/TIG but not flux core or stick. I guess I haven't been doing it wrong all these years. I'm pretty sure I saw that in a book (welder's handbook third? edition) but I don't recall the context, maybe the author was saying that about mig, and I just attributed it to all welding. quote:How much load is on the section you are welding on? Will a partial weld be acceptable? I guess they have to support my fat rear end but also act as some sort of protection for my rocker panels as well. I don't go crazy off roading but I'd like them to at least help with preventing damage. So I figure that welding them all the way around would be the best idea. quote:Welding short sections and letting the part cool between welds will also help. What would you suggest for this? My instinct tells me that if I'm going to do this I should: Tack weld all four corners, opposite diagonally let cool. Weld one short edge and immediately weld the other short edge? Then weld half of each long edge, like top right, bottom left, let cool Weld the other half of each long edge? top left and bottom right? Or should I weld the middle inch on each (long) side and then the "outer inches"? after things cool? Also, I'm pretty sure I've learned from this thread that overlapping the welds is a thing that exists and is good (assuming done properly).
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Jan 22, 2023 21:41
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I wouldn't overthink it too much. That is a thick piece of metal. You can weld a similar size piece of scrap first, if you want to be sure.
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Jan 23, 2023 19:11
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 What are the odds I can get a 32mm hole bored out to 38mm by putting my step bit (which maxes out at 32) in at a bunch of different angles? A potential catch is it's in the corner so on two sides my angles are limited. It's for a sink drain in my mobile darkroom. It's otherwise a $55 (at least) tool I'd be using once for 30 seconds, and getting rid of when I move overseas in 5 months.
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Jan 23, 2023 20:22
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A solution might be filing it into the right shape with a big, rough file.
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Jan 23, 2023 21:21
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Dance Officer posted:A solution might be filing it into the right shape with a big, rough file. That's another tool I don't have  I could probably borrow a file from the maintenance staff when I'm back at work in a week or two, but was hoping to get it sorted before the weekend (have another shoot). I do have a set of really small ones but it'd be a Sisyphean task.
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Jan 23, 2023 21:53
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That is the perfect job for a half-round bastard file, but most any will do the jump with varying degrees of effort.
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Jan 23, 2023 22:03
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Ethics_Gradient posted:
I feel like that's going to make a very messy hole even in the best of cases.
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Jan 23, 2023 22:03
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Drill a bunch of 1/8" holes in the diameter you want very close together, then beat the metal connecting them together with a flat headed screwdriver and hammer until it breaks loose, bend/press fit whatever inside of the absolute disaster of a hole you just made and seal with RTV
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Jan 23, 2023 22:13
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immoral_ posted:That is the perfect job for a half-round bastard file, but most any will do the jump with varying degrees of effort. I'll ask around with friends and see if anyone's got one, probably more likely than something as specialised as a big honkin' step bit. Hadlock posted:Drill a bunch of 1/8" holes in the diameter you want very close together, then beat the metal connecting them together with a flat headed screwdriver and hammer until it breaks loose, bend/press fit whatever inside of the absolute disaster of a hole you just made and seal with RTV Haha, I love this. The lip/flange around the drain will likely hide a lot of the messiness, and I was already thinking about bashing the area around it down a bit so the liquid does a better job flowing into the drain. Gonna see if I can source a file first though.
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Jan 23, 2023 22:18
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If this is sheet metal, my go-to would be either a hole saw or a large-diameter step bit (the kind where you need at least a 3/4" pilot). If it were a little larger, I'd just mark it, drill a pilot and use tin snips.
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Jan 24, 2023 04:21
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Peerless makes some crazy 36" wide differential axle that shares enough DNA with go karts that they're mostly compatible with 1" go kart axle....stuff. There is a lot of 1" go kart axle stuff out there. Welded in some axle bearing brackets, the notched the frame. Axle slid right in first try. The differential itself is not a load bearing part, oddly, so I still need to fabricate some kind of undercarriage and add more axle bearing brackets. Welds are not improving. Just going to accept that and move on. "The grinder makes me the welder I ain't". Might need to move wire speed up a bit. Probably need to just weld faster, I get overly obsessed with the "weld puddle" rather than laying down a consistent bead. Burned a couple of holes in some welds, got to manually build up the joint and close the hole which is an interesting task.    The axle bearing brackets allow the bearing to "float" a bit before being locked down, allows for all sorts of wildly out of square alignments. They make a 2 bolt and a 3 bolt model. I thought I'd order the more sturdy 3 bolt, but realized when it arrived that it's not compatible with my frame so gonna have to order a set of 2 bolt for the outside. Upgraded from my crazy expensive 3" 12v bosch 20,000 rpm and ~1 amp angle grinder to a harbor frieight 8 amp 4.5", that thing goes through 16 gauge like butter. Like going from a bic pen to a fat tip sharpie. The bosch is miles better for doing detail work like following precise curves Hadlock fucked around with this message at 09:47 on Jan 24, 2023 |
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Jan 24, 2023 09:43
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Thanks for the advice guys - Bunnings had what looked like a halfway decent half round bastard file for AU$19, or a set of like 9 files that included a half-round bastard file for $17, so I bought the set (doubtless garbage-tier, but only have a couple more months left before I move). It got the job done. I think the thickness of my sink (actually a commercial baking tray) is more than a standard sink, so back I go tomorrow to source a longer centre bolt to secure it. I have a set of little fasteners leftover from another project but they only go up to M4, the bolt in question is M5 Hadlock posted:Welds are not improving. Just going to accept that and move on. "The grinder makes me the welder I ain't". Might need to move wire speed up a bit. Probably need to just weld faster, I get overly obsessed with the "weld puddle" rather than laying down a consistent bead. Burned a couple of holes in some welds, got to manually build up the joint and close the hole which is an interesting task. This entire darkroom setup is basically a hate crime against carpentry or the abstact idea of "craftsmanship". I did spend part of the afternoon tidying up wiring for the reverse camera and safelight after getting tired of looking at them hanging/taped to the wall.
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Jan 24, 2023 11:35
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Anyone here work with robots? I'm studying the dark arts of machining at a vocational school, and I got a chance to train/learn on a ABB IRB 1410 6-axis robot. The thing is, the teacher that knows this subject was moved to another school, and they took the materials with them... so I'm left with basic documentation how to use/program this thing. Is there any place where I could find more detailed/in-depth info on using this? (Aside from Google/YouTube) ABB seems to have a online library, but it's locked behind a login, and registration may or may not involve NDA's and other strange things 
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Jan 25, 2023 15:21
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Robots are a deep dark art I'm hardly familiar with, but I do know some things: RoboDK is a rhino plugin that can do offline programming for many robots, it's what we use for our cobots when we aren't teaching points manually. It's not the most powerful or tweakable compared to what I'm used to in CAM but it can get most things done. RobCAD is the industry standard for automotive automation and what our robot consultant used when we needed industrial robots vs cobots for a project. I spent a lot of time looking over the guys shoulder as he worked and it looks like a wild program, didn't seem very intuitive or easy to use. Most training is pretty heavily gatekept, I don't know if there are online resources unless you have access through the manufacturer or reseller. I was going to go to kukas training school but it was two weeks and I couldn't justify it, so I stick with our universal robots and their 2 day intro course. Large industrial robots are some of the scariest machines I've ever worked with and I would take safety incredibly seriously. Make sure to tape out the work envelope on the floor and strongly consider rigid guarding or a light curtain or radar based safety system. Cobots scare me marginally less but we still take safety seriously with them. Best of luck and if anyone knows more I'm also curious, I'd love to be more comfortable with robots.
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Jan 25, 2023 19:22
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You could try getting a login to the online library, the worst thing that can happen if it requires NDA nonsense or something is that you decide it's not worth it.
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Jan 25, 2023 19:41
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Many years ago I played around with building tiny 8 inch long robot legs using arduino stuff and $50 servos and still managed to injure myself and break the servos by overdriving them. One wrong value can send the robot arm or leg into space your body is occupying. When a computer program crashes it just requires a debug and restart. When a computer program breaks your skin there's real physical harm done, heed meowmeow's safety suggestions
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Jan 25, 2023 21:09
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I have one in my living room right now, that I've been trying to get going. Long story. Gonna get it to play the knife game
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Jan 25, 2023 22:55
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Been a while since I've posted some work, so here's some I did before christmas, and some I did this week: Needing a present for my brothers in law, I decided to make some cowboy style pot hangers for a campfire, but I wanted them to be take down-sized so they could fit in a backpack. First up is the main stem, with a bend in each:  Then the top part of the stem, with a decorative hoop, though I suppose if you were to use both at once you could use these to hold up a bar to hang things off of and span an entire firepit.  Next is a handle, a series of coils, and some delicate balance work for the cantilever arms:  Round bar, turned on the lathe and drilled out (gently caress do I ever love being able to do little things like this, doing this by hand in a drill press is a huge pain in the rear end):  Sized, approximately, to hold the top part of the stem.  Welded, beeswaxed, and handle brushed lightly with a brass brush to get that gold ~patina~.  It's really hard to get a good picture of these things put together in the orientation that they're meant to be used, but hopefully this gets the idea across. I am pulling down on that cantilever arm in this picture, it's self-supporting, and it holds better the more weight you hang on the arm. You can move it up and down, and turn it 360' to get it into and out of the fire.  Now for the carrying case, starting with a little canvas:  Pockets sewn in, webbing added:  Button snap, nice neat little package. Bonus shot of my sewing anvil.  Quick S hook with a hole punched in one end (the one you can't see, because I am a good photographer  ). BiL wanted this to hang some stuff on his carpenter's tool belt I believe. This week's work I made a poker. Friend of a friend asked me to make a birthday present for her husband. Started with 20mm round bar, hammered it square over most of the length, drew it down to a taper, gave it a twist, and chiseled a pokey bit on the end:  Decided to use my stamp on this one, because why not.  The whole idea for this one was to use a Harley Davidson grip handle for the poker. By some miracle I had a piece of pipe that I bought probably 12-15 years ago that was just about the right size to fit in said grip.  Poker goes in the tube, tube goes in the handle.  I tack welded the poker into the tube (in the back, where you won't see it). Then I sprayed wd-40 into the rubber grip and tapped it on with a rubber mallet (thanks for the wd-40 tip Lloyd  ). End product is pretty decent. It's straighter, though by no means perfect, than it looks in this picture, perspective got a little screwed up when I took the picture. It's a little rough on the toolmarks in a couple places because holy poo poo I was tired from doing that kind of hand-drawing, I haven't done anything that heavy in ages. All in all about a 3 hour project, and for once the majority was hammering time. 
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Jan 27, 2023 17:03
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Hadlock posted:Background: Boxing the bottom of the frame from this:  to this war crime of metal fabrication:  Had some fun pounding 1/8" flat bar into a curve on the vise with a 2.5 lbs hammer. I put measurement marks in sharpie every 1" and then roughly whacked it into a curve. I was expecting the resulting curve to be extremely, uh, "polygonal", but I'd over-bend part of it, then stick it in the vise to flatten out the curve which seems to have imparted a more gradual curve across the entire... gradient. These two bottom pieces are practice for the top curved bits which will be a lot more visible. Not sure why I'm so fixated on getting this part of the frame so correct, but I guess some curves and flair (  ) is what prevents the frame from looking like a box on wheels, which is exactly what I'm trying to avoid. Here's a fairly vanilla small batch "production" frame some guy out in oklahoma is doing. Functional, but boring  : (not mine) Boxed the frame that I cut the bottom off of. Using hardware store 1" x 1/8" flat bar (0.125) to box the bottom of 16 ga (0.060). I am going to grind the newly (re)boxed sections flat for aesthetic reasons. Seems like there is some controversy about weld strength after dressing. I think because 1) the bottom of the tube (curved part) is the least stressed in the vertical direction 2) bottom of tube is 11 gauge vs 16, should be plenty of weld surface and perhaps most importantly 3) it's a loving go kart, it should be fine. The vehicle's all-up weight ought to be 240-275 lbs with most (70%?) of the bias on the rear which will be... substantially more stout. The front axle will sit on leaf springs too so shock loading ought to be plenty fine for this application. Not planning on grinding down the rest of my welds as they're/they'll be hidden. I think after we move I might invest in a TIG setup, I have always wanted to do a steel and later titanium frame. I guess TIG takes longer, but also you don't have any spatter, and is way, way cleaner. Flux core is proper glue gun and just wrecks my "shop" every time I pull it out Edit: welds are kind of improving(?) I think these are a tad on the cold side (sticker on the welder says C-C.5, this was more like B.75). I did ~5 feet of the same general weld and was able to dial in motion, heat, wire speed. Starting to feel a little more confident with the welder, given I have had nobody giving me tips. I'll find out more when I grind this stuff flat. I have a 24 grit grinder which should hopefully make short work of this stuff, not looking forward to that part. I guess that's why they call it finishing 
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Jan 27, 2023 19:17
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JointHorse posted:Anyone here work with robots? Rhino/Grasshopper + a plugin is a reasonable workflow. Take a look here https://www.food4rhino.com/en/app/robot-components It's actively maintained and free! iirc Rhino has a good trial, and 80%+ discount for education.
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Jan 31, 2023 15:04
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 On this roof rack, how would you fabricate the part highlighted in red? Is that just a chunk of 4" wide 1/8" flat bar that's been cut/ground down to that curve about 2" wide? Presumably the cross bars are whatever the metric equivalent of 16 ga 1/2" square tubing is, run through some kind of three roll bender. Whoever can bend my 1/2" round tube probably has that roll bender thing too. I've looked at a lot of these and this seems to be the universal design for this car, particularly taxis, and taxis of that era probably have phenomenally sturdy roof racks via lots of trial and error because the trunk didn't hold all that much.   
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Feb 1, 2023 09:40
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Hadlock posted:
I’d draw it in CAD and CNC plasma cut or waterjet it out of sheet of whatever thickness needed. Or I’d find out which of my friends had a plasma cutter and then cut it at their house.
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Feb 1, 2023 10:42
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Hadlock posted:
The same roller used for the square tube should be able to roll the flatbar. The round tube would be done in a pipe bender, not rolled.
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Feb 1, 2023 12:29
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I'm trying to further dial in speeds and feeds on a VMC. I mainly cut 420 PH. In terms of manufacturer recommendations for speed and feeds, does anyone know if 420 PH would be closer to general 400/Martensic SS or 17-4PH? I can't really seem to figure this out.
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Feb 1, 2023 18:20
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A Proper Uppercut posted:I'm trying to further dial in speeds and feeds on a VMC. I mainly cut 420 PH. In terms of manufacturer recommendations for speed and feeds, does anyone know if 420 PH would be closer to general 400/Martensic SS or 17-4PH? I can't really seem to figure this out. https://www.practicalmachinist.com/forum/threads/is-420-ph-stainless-different-than-420-stainless.244487/post-1789130 It sounds pretty nasty. sharkytm fucked around with this message at 20:25 on Feb 1, 2023 |
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Feb 1, 2023 20:21
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Reading practicalmachinist always makes me think that Americans still commonly use HSS tools, is there any truth to that?
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Feb 1, 2023 21:19
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Dance Officer posted:Reading practicalmachinist always makes me think that Americans still commonly use HSS tools, is there any truth to that? I can't imagine they'd be used in production but in maintenance I use them all the time, because we can't always find or afford carbide tools other than the most basic inserts. Better to be able to grind something myself.
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Feb 1, 2023 21:23
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I use a bunch of HSS, but my work is primarily hobby and prototyping work. Some of it could also be that American machinists tend to skew pretty old or are basically running on oral tradition, as evidenced by other elements of Practical Machinist*  *And capital taking the vast majority of manufacturing jobs abroad in the 70s.
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Feb 1, 2023 23:27
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NewFatMike posted:I use a bunch of HSS, but my work is primarily hobby and prototyping work. Same. Working in a school lab means there isn't much of a time crunch and we don't make that many parts, so running slower is no problem, and there are lots of weird one-offs and edge cases where being able to grind a custom tool on the spot is a big benefit. Also we mostly work in plastics and soft metals, so being able to bring a tool to a razor edge is helpful. Sagebrush fucked around with this message at 00:20 on Feb 2, 2023 |
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Feb 2, 2023 00:16
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Sagebrush posted:Same. Working in a school lab means there isn't much of a time crunch and we don't make that many parts, so running slower is no problem, and there are lots of weird one-offs and edge cases where being able to grind a custom tool on the spot is a big benefit. One part that's a personal hell for me is cutting pockets in rubber belts. Think timing belt but 6 to 15" wide and 20' long. All custom ground razor sharp hss. Other than that, a couple old guys is it. 99% carbide. For feeds and speeds check out machining advisor on the helical tool website. They get very specific about materials and if you can find a similar end mill it'll be pretty close. Just match diameter, length of cut, flute count, and variable or non variable pitch.
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Feb 2, 2023 00:35
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NewFatMike posted:I use a bunch of HSS, but my work is primarily hobby and prototyping work. The trades are full of either dinosaurs or people who were trained by dinosaurs. I grew up in a contractor family and recently got a job doing prototyping the kind of equipment we'd install, and the difference between what you learn from an old tradesman and what you learn from engineers in the industry is night and day.
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Feb 2, 2023 03:35
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