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CarForumPoster posted:Good points. For comparison for US people wanting a home shop (My example is a bit of an oversimplification): This is excellent info. For my setup the limiting factor is the impedance of the the power feed. While I have a nominal 200A/240VsinglePhase service, I have found that trying to draw 200A quickly will lead to brownouts in my immediate neighbors due to supply impedance. I am at the end of the supply line so am a bit of a worst case. For my big spindle, I ramp it up slowly as full power it is only 70A or so steady state. The problem is the surge current if trying to start it quickly. While I nominally have 64hp (200A) on the electric supply there is no way I can actually draw that and not explode the local grid/transformer. Also, the inrush for my 44hp VFD is negligible versus the running current for the 22hp spindle. Realistically, I have found that for me, 120A is the max I can draw without dropping the local grid by >15%. This will vary. While my local electric company will happily install a "200A" service, the will be most unhappy if you actually draw 200a for more than a fraction of a second. Also note that they will be equally unhappy with a load dump from that size of motor and you should plan to have sufficient breaking resistor capacity. This all applies to residential services in Canada. I can imagine that other areas will have other issues.
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Jul 15, 2017 07:13
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The biggest plug you can expect in a european home (uk excepted) would be a 3-phase 16A@400V socket. With that you can usually direct start a motor up to 5kW, with a soft start, or Y-D start you can go up to 7.5kW but around there you hit the limit of what a homeowner can expect to start. The next step up is a 32A socket and that's usually only found in places like my parents greenhouse farm or in professional shops.
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Jul 15, 2017 07:27
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His Divine Shadow posted:Been thinking of making a propane forge (from an old compressor tank I got) but the refractory material I was thinking of (ceramic wool) I am reading has asbestos like properties wrt cancer and health, so I don't think it's something I want to drag home.... Any tips on alternative forms of insulation, I've heard all kinds of stories of people using stuff like cat litter which is some kinda clay. Just wear a gas mask while building it. Once the facing material (some kind of refractory cement, which may be DIYable with kitty litter) is in, it's not gonna break out and hurt you. The cheapest cat litter is bentonite clay, which is used in making casting sand for moldmaking to cast metal. Chillbro Baggins fucked around with this message at 07:41 on Jul 15, 2017 |
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Jul 15, 2017 07:38
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Bad Angus! Bad!
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His Divine Shadow posted:Been thinking of making a propane forge (from an old compressor tank I got) but the refractory material I was thinking of (ceramic wool) I am reading has asbestos like properties wrt cancer and health, so I don't think it's something I want to drag home.... Any tips on alternative forms of insulation, I've heard all kinds of stories of people using stuff like cat litter which is some kinda clay. Fire Brick is a good place to start if you can get it for cheap. Keep an eye on craigslist/kijiji. The cat litter you're looking for specifically is made of bentonite clay. You want it for its calcium aluminosilicate, which is a refractory material. Do not get clumping cat litter or sawdust cat litter. Avoid fragranced cat litter. There are some guides on youtube about converting cat litter to DIY bricks but I haven't been able to follow their processes. Pond liner and/or pool liner is rumoured to be made of the same clay but ground up finer. This would be better probably.
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Jul 15, 2017 08:00
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Well on the topic of something else, what's this burning smoking pile in the ground? Why it's an old fashioned tar pile. Centuries ago swedish tar was exported to the world and well known for quality, most of it actually came from these parts in Finland which was then part of Sweden. This project's been 5 years in the making and last night was the culmination when they started tapping the tar, afterwards it'll yield some high quality charcoal.
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Jul 16, 2017 07:05
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Is that smoke flammable? Here's a video where they make charcoal in a less traditional way but collect their flue gases for combustion. https://youtu.be/Zzv6fIDsNwM?list=FLh6E4iam_dIHwrP7LGZOTOA edit: A thing I dislike about their design is it requires an external heat source to get going, which in my opinion kind of defeats the point. Has anyone heard of a Joseph stove?  DreadLlama fucked around with this message at 17:25 on Jul 16, 2017 |
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Jul 16, 2017 17:16
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His Divine Shadow posted:Been thinking of making a propane forge (from an old compressor tank I got) but the refractory material I was thinking of (ceramic wool) I am reading has asbestos like properties wrt cancer and health, so I don't think it's something I want to drag home.... Any tips on alternative forms of insulation, I've heard all kinds of stories of people using stuff like cat litter which is some kinda clay. Ceramic wool can present a respiratory hazard but it's nowhere close to being on asbestos' hazard level. Keep it bagged up in storage and work with it with respiratory protection and seal it in with a high-temp refractory cement over top and the risk it presents is negligible. Cat litter is an atrocious refractory material, don't even consider it. It's the option of first resort for amateurs because it's accessible and can handle the heat but it's a big heat sink that makes for an underperforming forge. it'll make for a forge that runs cold and won't come to temp in a reasonable timespan. If you have access to proper insulating kaolin/ceramic wool, use it. Forges need a light, airy insulation that lets the forge reach operating temp fast. Ambrose Burnside fucked around with this message at 01:36 on Jul 17, 2017 |
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Jul 17, 2017 01:08
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I'd still like to know about any / all alternatives, don't plan to begin building anything this year and am looking to get as much info as I can on this. In other news I cut my earth cable in two, had issues on low amp tig welding (unstable wandering arc and HF lightning), found some damage on the cable and cut it there. Still more than long enough since my welder is 99% of the time parked and hooked up to my welding table. Works better now though I think improvements can still be made. I am wondering if I should weld the copper from the cutoff cable onto the underside of the side of the table where I hook up the earth clamp. Maybe I need to open it up and look over the catalytic capacitors and see if they are all in good shape still, 23 year old machine...
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Jul 17, 2017 08:36
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I am also extremely interested in propane forge advice, I've been wanting to dip my toes into metalworking for a while and a propane forge seems like a drastically easier way to get started with heating and beating metal than a coal forge. On a somewhat related note, what would people recommend for a good way to start to learn welding? I don't even know what kind (I am too dumb to know the difference at this point), just interested in sticking bits of metal together and having them stay together for making stuff.
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Jul 17, 2017 22:52
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Ambrose Burnside fucked around with this message at 02:20 on Jul 18, 2017 |
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Jul 17, 2017 23:18
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Are all refractories the same as far as catalysis and secondary combustion are concerned? According to someone on youtube (https://www.youtube.com/watch?v=ZYyKUePdC2Y&t=111s), pumice stone and crushed flower pots are good for breaking down long carbon chains.
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Jul 18, 2017 01:11
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Magres posted:I am also extremely interested in propane forge advice, I've been wanting to dip my toes into metalworking for a while and a propane forge seems like a drastically easier way to get started with heating and beating metal than a coal forge. You'll need a friend with a machine shop to build the burners. Or a really good drill press and steady hands. Plans are available online easily enough. Really all you need is a sturdy metal box with holes in it to hold your insulation. Kaowool is good for the outer bit, but you'll need harder stuff (brick, ceramic of some kind) inside to stand up to scale and super heated iron. Given the time it takes to source all the bits (like good luck getting the high pressure regulator, those things are a bitch to find on their own), it's much easier and not very expensive to buy a prebuilt unit. If you want to roll your own don't let me discourage you, do it if you want. Welding is easiest to pick up during night courses at your local trade school. Unless you have a friend with all the tools and a bunch of practice materials. Start with oxy/acetylene if they offer it, it's the best fundamental foundation. Don't bother with mig courses, mig is easy mode after you know how to stick, Tig and o/a weld.
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Jul 18, 2017 20:03
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Slung Blade posted:Start with oxy/acetylene if they offer it, it's the best fundamental foundation. Don't bother with mig courses, mig is easy mode after you know how to stick, Tig and o/a weld. Eh...I think stick welding is the best starting point, personally, because it's got the least number of variables to worry about. You can focus on arc control, getting smooth motions, and putting down the right amount of metal. Then move on to TIG, which does everything oxyacetylene does but better and faster. Once you understand the TIG process, you can pick up oxyacetylene welding in a few minutes if it ever becomes necessary to do so. I agree that MIG is easy mode, but it's also way more dependent on getting the correct machine settings, and it's not always obvious what needs to be changed when something goes wrong.
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Jul 18, 2017 20:49
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I need to design an arbor/workholding solution for turning rings, the jewellery sort, on a lathe. We can't let people work from the full length of stock as per usual, and they should have access to the outer surface, inner surfaces and sides between one or two fixtures. Custom jaws for self-centering chucks deals with holding the stock for drilling/boring the inside, but the arbor for the top and sides may get tricky as there could be a huge range of IDs it'll have to accommodate, and turning an arbor for every ring size isn't feasible. Maybe a second set of jaws with 'fingers' to grip the ring on its inner surface while leaving as much as possible open for machining?
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Jul 19, 2017 16:44
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I bought a 45 degree 50mm Chinese face mill and some SEHT1204 cutters. When I do the screws up on the carbide cutters, a couple are still loose. The face mill add said 'for SEKT1204' cutters, but would this make any difference on the fit? The third letter just looked like a tolerance letter to me.
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Jul 20, 2017 10:34
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Mudfly posted:I bought a 45 degree 50mm Chinese face mill and some SEHT1204 cutters. When I do the screws up on the carbide cutters, a couple are still loose. The face mill add said 'for SEKT1204' cutters, but would this make any difference on the fit? The third letter just looked like a tolerance letter to me. Comparing This and This the geometry looks different, so maybe more than that.
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Jul 20, 2017 11:15
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Ambrose Burnside posted:Custom jaws for self-centering chucks deals with holding the stock for drilling/boring the inside, but the arbor for the top and sides may get tricky as there could be a huge range of IDs it'll have to accommodate, and turning an arbor for every ring size isn't feasible. Maybe a second set of jaws with 'fingers' to grip the ring on its inner surface while leaving as much as possible open for machining? Sounds like it might be a job for and expanding arbor set. I have one and it works great for holding parts like that. They are usually used between centers but I have held them from one end in a collet chuck as well for small parts. You also would be able to make a set of one sided expanding arbors that would cover the ring size range.
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Jul 20, 2017 20:26
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ZincBoy posted:Sounds like it might be a job for and expanding arbor set. I have one and it works great for holding parts like that. They are usually used between centers but I have held them from one end in a collet chuck as well for small parts. Yeah, I was thinking about some sort of expanding arbor, i just didn't know they were a commercially-available thing. Which might not help, as the bosses want this to not cost more than the brass stock for the rings themselves. I'll take a gander at some examples to see if making our own stubby one-sided versions will be manageable. e: the commercial version i'm seeing are inconveniently-long. apparently lots of people have tackled shorter versions before, and the part i was stumped on- how to make the shorter mandrel expandd while lacking the length to use a tapered drift- is apparently handily addressed by using (tapered) NPT pipe plugs. seems pretty straightforward. Ambrose Burnside fucked around with this message at 02:28 on Jul 21, 2017 |
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Jul 20, 2017 20:55
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Ambrose Burnside posted:e: the commercial version i'm seeing are inconveniently-long. apparently lots of people have tackled shorter versions before, and the part i was stumped on- how to make the shorter mandrel expandd while lacking the length to use a tapered drift- is apparently handily addressed by using (tapered) NPT pipe plugs. seems pretty straightforward. You are right, the commercial ones are a bit long for turning rings. A NPT plug would work fine but I have made my own by turning a tapered bore and matching plug. The plug has a hole through it and a bolt is used to draw the plug into the taper. You just have to make sure you have a way to extract the plug when you are done if you are using a self holding taper. I have found I get good enough holding power with a 10 or 15 deg taper that is fairly easy to release.
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Jul 21, 2017 02:44
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Ambrose Burnside posted:Ceramic wool can present a respiratory hazard but it's nowhere close to being on asbestos' hazard level. Keep it bagged up in storage and work with it with respiratory protection and seal it in with a high-temp refractory cement over top and the risk it presents is negligible. How about https://www.youtube.com/watch?v=L-qOIO6IQWk carbon foam?
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Jul 21, 2017 05:20
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ZincBoy posted:You are right, the commercial ones are a bit long for turning rings. A NPT plug would work fine but I have made my own by turning a tapered bore and matching plug. The plug has a hole through it and a bolt is used to draw the plug into the taper. You just have to make sure you have a way to extract the plug when you are done if you are using a self holding taper. I have found I get good enough holding power with a 10 or 15 deg taper that is fairly easy to release. That's a good idea, yeah- I was thinking about driving it with a mallet and a stubby plug would probably want to skew and expand the mandrel unevenly/have less holding power than a longer drift, a screw handles that. Ambrose Burnside fucked around with this message at 11:55 on Jul 21, 2017 |
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Jul 21, 2017 11:52
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How do I test if my welds are strong enough? Trying to learn to weld here. I tried cutting through the weld to look at penetration but the metal looks the same the whole way through. Would buying a $300 hydraulic press for this purpose be total overkill?
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Jul 22, 2017 19:48
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Mudfly posted:How do I test if my welds are strong enough? Trying to learn to weld here. I dont know a lot about welding tests but it seems sorta pointless unless you have a spec youre testing to. The only spec I can think of for a hydraulic press is a straight tensile pull that proves it fails in the HAZ and not in the joint...but is that actually a valid specification?
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Jul 22, 2017 20:17
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For testing welds, I use a 4-pound engineer's hammer. Maybe an 8-pounder if it's safety-critical.
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Jul 22, 2017 22:18
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Is there an issue of "Good, it survived a blow with my hammer. The weld was good. However after hitting it with a hammer I better re-weld this". What are you looking for when you strike it? Total failure or some subtle changes? e: I'm making a milling machine stand, my plan will be to load it up with 500kg of weight then jumping on it a bit. If it survives ok, the mill goes on. The mill weights 400kg.
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Jul 22, 2017 22:28
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The weld should ideally behave more or less the same as the base metal- the ideal weld, after all, is a totally-homogenous join that's indistinguishable from the joined components- so I just subject it to whatever I think the part will be subjected to in practice and then a bunch more if the object itself can take it. Hammering a bunch on the weld/a test weld and trying to bend it over on itself without either operation leading to visible cracking or join failure has been good enough for me for non-critical applications where there's no risk of anybody getting hurt or dying if the weld -does- fail. A mill stand isn't a trailer or a vehicle but it isn't exactly cosmetic, either, so I wouldn't be too flippant about the welds. Consider the worst-case-scenario consequences of said stand failing catastrophically- maybe the mill gets damaged, maybe you lose a foot or a leg or whatever if it tips, I dunno but I like to catastrophize- tally up those costs, then factor in your welding experience/confidence and how much getting it fabricated will run you. There's no single answer to that equation, you just want to have your eyes very open when you're trusting a fair bit of money (and maybe your health) to your welds. Ambrose Burnside fucked around with this message at 22:49 on Jul 22, 2017 |
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Jul 22, 2017 22:42
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Mudfly posted:Is there an issue of "Good, it survived a blow with my hammer. The weld was good. However after hitting it with a hammer I better re-weld this". That seems like a pretty good test (although you should probably try to put 2x+ the needed weight on it) since you know the spec and are exceeding it. Now whether the vibration or corrosion cracks the welds later is a diff issue but thats what paint and inspection are for.
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Jul 22, 2017 23:27
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You can probably also design the stand so that the full weight of the mill is not actually transferred solely through weld anywhere. E.g., have upright steel posts under the weight of the mill, weld the posts to the surface of the stand, and the weight is being transferred from the surface to the posts by gravity, with the welds serving to protect from lateral forces only. That said: here are the various weld testing methods, including the nondestructive ones: http://www.lincolnelectric.com/en-us/support/process-and-theory/pages/nondestructivie-weld-detail.aspx After visual inspection, the nondestructive method most accessible to you (I'm assuming you don't have an xray or ultrasound machine etc.) might be fluid penetrants: https://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Dindustrial&field-keywords=weld+check+ Check the first three items on there for the three-part test where you spray on a penetrant, then wipe it off (leaving some in any cracks that are there), spray on a developer (which causes the stuff in the cracks to change color or become visible to a flourescent light), and then a cleaner for removing the stuff you sprayed on. A three-part kit is under $40 and if you use it sparingly it should last a good long while. Of course, this stuff just reveals tiny surface cracks and bubbles, it can't tell you how well your weld has penetrated, whether there's bubbles down inside the weld, etc. I think what you should do (and what I'm planning to do as soon as my welder is working) is to practice on the same material, do visual inspection, do destructive inspection, and then when you're confidently laying down good welds that pass inspection, just go ahead and weld up your stand using the same techniques. Assuming a design that does not overly stress the welds, you'll probably be OK.
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Jul 23, 2017 01:31
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I've done shear wave UT testing and pulse-echo UT on welds. Works well, but you need to know what to look for and have about $12k worth of equipment. Dye penetrant is slightly more affordable but only helps you on the surface. Personally if a weld sounds good, looks good, and takes a whack with a hammer, it's probably good for what you're doing. Like leperflesh said, design it so the welds aren't load bearing but just structural. There's a train yard next to our shop and they don't do any UT testing and the likes. All you have to do is pass a few welding tests where you do a butt-weld, an angle weld, and a root weld. They either stick it in a vice and bend it, or in a press. As long as the base metal fails first, you pass.
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Jul 23, 2017 01:43
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And if you're still unsure, then go the tried and true method of overbuilding the poo poo out of it: use 3/8" steel instead of 1/4", and add extra supports, cross members, gussets, etc anywhere you can. Most of the stuff I put together is ugly as poo poo, but will probably outlast my kids.
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Jul 23, 2017 05:24
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Yeah I might settle with the overbuilding route. My first project might be a fairly light weight table, and I'm looking for a way to clamp it to my existing wooden table as a flat surface reference. Would right angle magnetic clamps be good for this? Those triangle ones. Then I need to start deciding 'how flat is flat enough' for my mill table and other metal work tables, urghghghgh. I can feel the OCD kicking in.
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Jul 23, 2017 11:36
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If I get a length of A2 and grind a bevel on one end of it, how close am I to a serviceable chisel? This is just for cutting mortises in pine, but they need to be 8 inches deep. Chisels that long are expensive. Reference regular chisel:  Fancy long chisel:  Can I temper in a toaster oven? 
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Jul 23, 2017 20:43
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DreadLlama posted:If I get a length of A2 and grind a bevel on one end of it, how close am I to a serviceable chisel? This is just for cutting mortises in pine, but they need to be 8 inches deep. Chisels that long are expensive. I took a timberframing class a few years ago and had to get a Barr chisel.  Beyond just a cutting edge the sides are cut at a relief angle. It's slightly thinner at the tip than at the socket. When I ordered the chisel they told me it's made out of 52100 bearing steel. Chisel nerds can wax poetic about the merits of O1 Vs. A2 Vs. Whatever, but unless you're making a living with it, I think you'll be fine with A2. Yes, a toaster oven will temper it to 60 Rc at 400 F. I've heat treated grinding guides that look similar to a chisel body and warping and cracking is the biggest problems we run into. Slow and steady.
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Jul 23, 2017 23:39
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DreadLlama posted:If I get a length of A2 and grind a bevel on one end of it, how close am I to a serviceable chisel? This is just for cutting mortises in pine, but they need to be 8 inches deep. Chisels that long are expensive. You should definitely be able to find firmer/socket/timber framing chisels used for $20-$40. 1 1/2" will be expensive because it's the most common do-everything framing chisel, and larger than that is usually more expensive as well. 1" are cheap, and weirdo sizes like 1 1/8 are cheap too. Random examples http://www.ebay.com/itm/162594835720 http://www.ebay.com/itm/142451501566
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Jul 24, 2017 12:18
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 Anybody need a couple of thousand rail spikes? They pulled all the ties out on the tracks by my house and left this here.
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Jul 27, 2017 00:33
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Our local scrapyard calls the police anytime anyone brings in obviously railroad related stuff. How do I know? We tore up rails from inside one of our buildings and I had the pleasure of bringing it in to the scrapyard. 15 minutes later and I'm explaining how I'm not a
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Jul 27, 2017 01:00
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DreadLlama posted:Can I temper in a toaster oven? You can, and A2 is an air hardening steel, but this is how it's heat treated industrially and if all you do is grind it and then temper it, you will not get the same result: https://www.speedymetals.com/information/Material10.html At the very least, you will need to heat the steel to austenitic temp (1800F) before allowing it to air harden, and then temper in your toaster oven. You would ideally want to differentially temper the metal, with the last inch or so of the cutting end tempered to maybe 300F, and the handle end well-tempered to at least 1000F, maybe more, to give it toughness. What I hope you can see I'm getting at is that it is going to be a seriously finicky pain in the rear end to get the same result as buying a manufactured chisel. I would consider it, if I had a home forge, thermocouple, tempering oven, and a few dozen successes at heat treating less difficult steels under my belt.
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Jul 27, 2017 02:31
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Applesnots posted:
If you're serious, I'll take a pile. Pm me or get me at username at gmail dot com
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Jul 27, 2017 03:58
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Applesnots posted:
Not likely to be an issue, but be aware that railroad police ain't nuttin ta gently caress wit, and will just as happily nail your average joe who grabs a few loose spikes as they would meth addicts pulling poo poo off an active line.
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Jul 27, 2017 04:49
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Applesnots posted:
Yeah if you can confirm this isn't hella-illegal I'd like a few to just play around with 
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Jul 27, 2017 04:49
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