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Background: I am working on a go kart project, the wheel base is on the longer side at ~64 inches and it's a characture of 1920s open wheel F1 racers, so a main component of this is using 16 gauge (NOT 14 gauge, which is what most yards carry, had to special order this and wait three weeks) 3x1 rectangular tubing. Or however it's formally phrased. Anyways stylistically one of the key features is that it has a solid front axle that is leaf sprung on a ladder style frame. On a lot of these cars the front of the frame curls down to give proper clearance for the springs/axle assembly. How much it curls down is sort of like the beard or mustache of the car it imparts a lot of character of the car you're trying to build. This is what I am trying to emulate, at a characacture-level:  Bugatti's type 35 (probably what this car was patterned after) only curves down a tiny bit, this Ballot is probably 2-3 times that So there are two ways to do this, Option A, for the bugatti level of curve you can just notch the 1x3 where the curve starts, bend it down and trim to shape and line with 1" wide strip and tack/weld. I see a lot of guys doing that for minor curves, you don't need to cut extra stock you can just use what you have but you end up running a ton of extra welds and work   Option B is to cut extra 1x3 stock, weld it to the bottom and trace your pattern on there, line with a 1" wide stick and tack/weld (extremely crude ms paint example). You end up with a lot of extra metal (weight) in the frame rail though that's not doing much for you structurally  Option C I guess is, send a file over to send cut send and get the ends cut in 2D then weld them on the end and just trust the butt weld with no fish plates. Apparently not a lot of people report frame cracking as the all-up weight is only ~250 lbs + driver so even 16 gauge is ludicrous overkill for the task at hand. Options A and B at least have the "load bearing" part of the ~35 degree curve in virgin steel in line with the rest of the 90" frame rail
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Nov 14, 2022 18:26
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Basically I'm just looking for someone to be like, holy gently caress you're dumb, do it this way and stop overthinking it, please and thank you
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Nov 14, 2022 23:48
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Yeah I don't have those kinds of resources, this is strictly a 4" grinder and harbor freight flux core welder, two-off situation I suspect bending square tubular steel, especially not in a 1:1 ratio is going to be ..bad
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Nov 21, 2022 04:09
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honda whisperer posted:
Is this a.. 3 axis (x,y,z) cnc machine for $5k? Like could you realistically CNC a custom head for a LS1 or whatever with something like this. Fusion 360 + billet aluminum + time = engine parts I was under the impression that used these were like $20k used with computer control? That seems like a lot of precision steel for barely the scrap value?
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Dec 14, 2022 01:51
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Yeah that design is optimized for being cast and then milling the precision bits. Presumably there would be a design that's optimized for 3 axis cnc How much is a single CNC bit, like to mill that flat interface on the side of the head. I know there's basically an infinite variety of bits and quality
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Dec 14, 2022 02:26
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honda whisperer posted:If you want to billet small production you use a 5 axis machine. That would make that head a 2 setup job. Peering down the rabbit hole further, I'm not even a Chevy guy, but, if I had a STEP file for a billet LS1 head ready to go and wanted to do like, 20 of these for Hadlock's Super LS1 Billet "Headlock" Heads™ to sell commercially, what would that cost me out the door And yeah I do some 3D printing at home I know the complexity and what's in the step file has huge impact on machine time, tool swaps etc, just looking for a very broad ballpark figure
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Dec 14, 2022 03:14
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Ok that was a deep rabbit hole. I guess I need to eBay impulse buy a Shizuoka milling machine, and I guess upgrade my shedhonda whisperer posted:
Cool thanks sir. That's... Less than half of what I imagined, so very cool
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Dec 14, 2022 08:07
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ante posted:I have unlocked arbitrary thread pitches. New thread title?
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Dec 23, 2022 21:09
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Sagebrush posted:my new apartment has one of those glass stovetops and it is making me acutely aware of the unflatness of the bottom of my cast iron skillet. should i surface it with a fly cutter y/n Will you put these up for sale please on SA mart, I'll buy at least two
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Jan 16, 2023 20:34
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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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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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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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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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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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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 
Hadlock fucked around with this message at 19:32 on Jan 27, 2023 |
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Jan 27, 2023 19:17
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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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wesleywillis posted:Sounds lie the OP has mostly figured things out, but how hard would it be to cut a tapered piece of whatever the gently caress in half length wise and then machine the inside taper, put two halves back together? Seems like a good option Sorry didn't follow along too well, can you just get like, 9 drill bits and stair step your way to (pixelated) victory. Maybe do a hack job rounding out the stair steps with a die grinder
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Feb 8, 2023 03:25
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Try calling Berkeley Marine in Berkeley. They do tons of custom fabrication and periodically roll out a new construction boat from time to time, they will either know a guy, or can put your stuff in their next batch to be processed. They probably do a batch of hot dip at least once a month, I'd guess. Bay Marine has a yard in Alameda that probably knows a guy too. Bay Marine built all the new floating ferry docks/terminals in SF. And I think the new floating firehouse too. I suspect showing up in person and paying in cash can grease the wheels. BAE Systems has a shipyard in the dog patch too. They're not sending this stuff out of the area to get hot dipped.
Hadlock fucked around with this message at 08:13 on Feb 8, 2023 |
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Feb 8, 2023 08:02
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What is the risk profile of grinder dust to the home hobbyist. Grinding some welds flat for aesthetic purposes. As far as I can tell mild steel + aluminum oxide grinder wheels are mostly chemically inert, but as a full time employee, over the long term irritation can cause problems in the lungs. In my tiny home shop with the door closed to trap in heat, all that dust builds up pretty rapidly
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Feb 9, 2023 19:40
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Yeah I wore a lovely blue facemask when I cut a long strip out of some tubing and that was ok. Got in the habit of not wearing a respirator cleaning up weld spatter, and last night I was grinding down a bunch of welds and cutting up bar stock for brackets, definitely felt it today. I've got a fan next to my heater that was doing a great job of blowing dust from my work piece directly into my face. Lot of boneheaded decisions in retrospect I've got a 3Mhalf face respirator from the early days of the pandemic still in the package and a set of P100, I'll go dig that out What did guys do in the old days? Just wheeze until they got lung cancer and died? While smoking a pack a day
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Feb 10, 2023 03:01
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Maybe 2 months ago I was asking about milling an LS3 head Then I made the mistake of downloading an LS3 head STL (3d printer file) for one and realized you can't cast these using traditional one-piece/mould methods A week later down the rabbit hole, found this video. I guess they drizzle resin onto casting sand one layer at a time, and then you hook the "printed" sand bits together and pour in aluminum and you end up with a head https://www.youtube.com/watch?v=9N8v76SYICc I'm definitely not going to use them to cast me an LS3 style cross flow head for what used to be a flathead inline 8 Packard 357 but it's an interesting technology Edit: one more video showing their process from another perspective https://www.youtube.com/watch?v=_icw0HIw2jY Hadlock fucked around with this message at 20:16 on Feb 20, 2023 |
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Feb 20, 2023 20:08
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Is there a technique I can apply that yields the same result as using a contour Gauge, without needing to go buy one. I have a double ended piece that's gonna be notched on both ends to connect two other offset pieces, connected at an angle, kind of like a roll cage. Only thing I can think of is paper template + trial and error Contour gauge is perfect tool to 3D print, but has so many parts would take a week to print
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Mar 1, 2023 12:30
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Yeah I've deviated so far from the CAD at this point I'd spend more time remeasuring everything in the computer than the alternatives And yeah I'm not opposed to spending the $10 it's just that it's a toss up between time wasted driving to the nearest store (which is out of the way) vs loving around with paper templates and scissors and tape for four tiny things The cardboard isn't a terrible idea I might give that a shot. The gauge only needs to be about 3" deep and 2" wide
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Mar 1, 2023 17:33
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Ruler CAD is a good idea. Accuracy needs to be on average 1/8" or closer, can go up to a quarter inch on some handful of egregious fitting errors. I'm getting pretty good at bandaiding my fitment errors with flux core treating it like a more permanent hot glue gun 
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Mar 2, 2023 04:14
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You can buy MAPP on amazon? Pretty sure my local ACE had it when I went in there last
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Mar 2, 2023 18:56
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I was curious this is what I found MAPP gas: https://www.homedepot.com/p/SIEVERT-14-1-oz-MAPP-Gas-Cylinder-1-in-Valve-No-Regulator-Required-221197/318912570#overlay Safety Data Sheet: https://images.thdstatic.com/catalog/pdfImages/3a/3a2adc69-ed2d-4f70-bb8c-91ec4a703700.pdf Composition/information on ingredients Propene 100% flame temperature of up to 4175°F MAP/Pro: https://www.homedepot.com/p/Bernzomatic-Bernzomatic-14-1-oz-Map-Pro-Hand-Torch-Fuel-Cylinder-332477/203226566 Safety Data Sheet https://images.thdstatic.com/catalog/pdfImages/77/7799980f-17cc-4ff9-af62-c8dc0178bbde.pdf Composition/information on ingredients: Substances: Propylene 99.5 - 100 Impurities Propane 0 - 0.5% Flame temperature in air of 3,730° F / 2054.4° C
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Mar 2, 2023 19:16
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Thought about this some more and realized you only need a contour gauge when making templates where the end mating surfaces aren't right angles. Realized I'm just really dumb about templates. Created some, uh right angle end templates, taped them to the main frame, then taped a bigger connecting piece to connect the ends together, and then traced the stock over the template.  I did bird's mouth cuts on both ends of the bits on the right, the one at the back right has a single birds mouth and then the rest were more simple flat angles. Everything is spaced weirdly and at different angles because I'm trying to fit the supports around the engine in a kind of cramped space. Still a work in progress. Neat learning how to build life sized stuff in three dimensions but I'm very slow struggling through reasoning how to build this from scratch. Once I figure it out the subsequent ones go a lot faster.
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Mar 5, 2023 01:43
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I'm testing out some extremely high tensile strength filaments
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Mar 5, 2023 02:16
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In reality 1) apparently it's really popular to race these on smaller vineyard/orchard grounds, using the (mostly unmaintained) service roads as a race track, AND it's a live rear axle meaning the suspension is the frame, and if the frame flexes between the engine mount and axle the chain will come off. very common problem on these karts with undersupported rear subframes 2) the differential is two halves bolted together, is not structural so you need two support points for each half shaft on either side of the diff and perhaps most importantly 3) I have about 8' left of 1x3" rectangular tubing and no other plans for it also 4) it's 16 gauge (0.060") thin wall tubing so it's not nearly as stout (nor as heavy) as it looks. It's a little thicker than fender sheet metal but only barely. Common thickness for this tubing is 14ga (0.083") which weighs about 30% more
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Mar 5, 2023 20:29
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Why is 5/16 such a common bolt size? Is that sort of the "we definitely need 1/4", but that extra 1/16th of an inch gives us the safety margin where it's safely overkill"? Or is it just the minimum size where steel has a useful shock load and won't rust through in five years
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Mar 8, 2023 08:56
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So has there been a watershed moment in improvement in safety since like, I dunno pick a date, 1980? Seems like everyone my parents age (now 70) and older just grew up with "you do it how you do it, if you lose a finger, that's your problem" but on the other end of the spectrum you have the just-turned-18-yo kids who probably saw the "guy getting sucked into the industrial lathe via his shirt sleeve and turned in to sausage" when they were 12, and countless other grotesque gore survailence footage that probably should be age restricted to some degree, and those 18 year olds seem to at least be aware of, or attempting some level of PPE. The comments for any DIY video these days, half of them are the OP getting dragged for all sorts of sketchy safety stuff. Or maybe I'm just imagining things.
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Mar 20, 2023 02:38
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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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Broke my first drill bit last night on my harbor freight drill press. Drilled about 16 x 7/16ths for some rivnuts in alternating 1/8" plate and 16ga mild steel To horribly misquote Douglas Adams, "I really enjoy the sound as they go whizzing over my head" was only a 1/8th bit but definitely happy I was wearing eye protection Later another 1/8th bit broke off in the hole, didn't realize it occasionally the metal would PING like a string plucked on a guitar and the shavings would bounce. I thought I was doing great as the metal was pinging and the bit kept going lower. Turns out little 0.5mm pieces of drill bit were shooting off into orbit at the speed of sound  Then I realized I'd just drilled like a dozen pilot holes with that drill bit with no oil. Switched to a different drill bit and started using oil and problems went away. These bits all came out of a highly abused $12 Ryobi set from home depot like a decade ago so not torn up about it P100 working out great thanks for that call out Rivnuts are pretty neat especially when working with long lengths of square tubing Also made some really horrific high porosity welds (watching blisters of flux impurities bubble to the top and pop) just trying to use the flux core wire as a glue gun to close up some fabrication. So bad I didn't even bother taking photos. It's in a non structural part that's probably going to get ground way back anyways with body filler and paint.
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Apr 3, 2023 13:09
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Adventures in square tube bending First attempt did not go great, got some wonky angles where it ought to be straight.  Second attempt with wider, more gradual radius bend worked out much better Doing the thing where you make the pattern, draw the segments at an angle that also intersects a common point, then cut up the pattern, lay it flat and scribe the triangles between the patterns on the flat square tubing. I think it's supposed to work better on longer segments but I'm making it work. Generally I get within 5-10% of the final shape on the first try, then just trim some cuts to allow a tighter angle    Seems to be better/faster than the "spray and pray" school of turning the tube into an accordion with 4x too many cuts but I've only tried the first method so far Hadlock fucked around with this message at 06:43 on Apr 16, 2023 |
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Apr 16, 2023 06:34
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Can you even buy rivnuts/nutserts at retail? I bought a bag of 100 online and promptly lost it Harbor Freight and Lowes both sell the tool which comes with a handful of starter pack inserts but I don't want to buy an entire second tool I tried explaining this thing to the guy at ace hardware and he just looked at me like I was a space alien Edit: Grainger was about to order me some guy next day at... Actually competitive prices, that was a pleasant surprise Hadlock fucked around with this message at 21:04 on Apr 18, 2023 |
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Apr 18, 2023 20:15
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Welp, their computer service thing said tomorrow by noon, sounding like either a) it's not coming tomorrow or b) getting a potato. Sounds like I just paid $12 for a learning experience. The plan was to have the body bolt to the chassis as one piece using nutserts, I guess if it comes down to push and shove I'll spot weld it together now and do it the right way after the movers deliver it
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Apr 19, 2023 02:34
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I went into their "retail" cave (carved out of their giant regional warehouse) and ordered it for pickup the next day, and it's not super, super exotic, fingers crossed. My guess is that it's coming on the morning truck from Charlotte or Raleigh But yeah the guy was like "how will I let you know when it arrives?" And I was "well it'll be here tomorrow" and I guess I missed the southern nuisance of "uhhh, yeah" so I guess we'll find out Strong agree on McMaster Carr if you absolutely positively need it tomorrow by 10am but not in the budget this week unfortunately
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Apr 19, 2023 05:17
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The rivnuts arrived on time Downside is they're... Super tall looking? Like the threads are super deep set, like these are designed for thick wall steel or something. I'll have to take a closer look tonight Edit yeah these are technically compatible but need a much larger diameter drill, the ones I was using previously went in with a 7/16" bit, these need at least two sizes larger  Old is installed up front, old for scale. Item description from Grainger doesn't specify anything beyond the internal size and thread pitch Hadlock fucked around with this message at 22:06 on Apr 19, 2023 |
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Apr 19, 2023 21:43
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ante posted:I have unlocked arbitrary thread pitches. Bring back the good thread title
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May 1, 2023 06:11
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If you avoid talking to Lincoln/Miller die hards, nobody seems to be having any trouble with the latest crop of inverter stuff coming out of China, at least for light duty work
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May 3, 2023 02:37
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