To expand on what you’ve said, the fabricators/welders and the customer are all participating in their being left in the dark. A whole lot of assumptions are being made.
The fact is, many times tolerances are an afterthought added to a drawing because tolerances are required, NOT AS AN EXPRESSION OF HOW FAR FROM NOMINAL THE DIMENSION CAN BE AND STILL HAVE THE FABRICATED/WELDED ASSEMBLY FUNCTION. Again, the fact of the matter is many designers don’t know how far out a dimension can be without impacting function.
Another point someone brought up is “inspection dimensions”. Again, it’s a fact that THE DIMENSIONS NEEDED TO FABRICATE / WELD AN ASSEMBLY ARE SELDOM ALL NECESSARY TO VERIFY ASSEMBLY FUNCTION and THERE MAY BE CRITICAL ASSEMBLY DIMENSIONS THAT AREN’T CLEAR ON THE DRAWING . But there seems to be little concurrence on just how to express the difference.
There’s also the mention of “good” vs “bad” drawings. Anyone want to take a shot on exactly what’s the difference?
For me most of the Drawings I get have Dimensions of some areas repeated over and over, and then other Dimensions are left out.
Most of what I build is one off and most of the guys drawing it are not engineers.
Plus I think they get pushed to go fast! I almost always call and talk with who ever drew it and ask questions about all kinds of things. Most of what I build is 1.25 to 2" sq tube and some times they don’t even call out wall thickness. I will ask and they say well what ever you think. But with that said most of what I build is not critical.
No ones life depends on it!
I always have questions and I’m not afraid to ask.
Well, I think part of your problem is that your tolerances are too loose or missing. You got frames at about 0.120 out of flat, but you spec 1/16" for twist (ref. B4) PLUS fractional tolerance of 1/16" (ref. B2) for a total of 0.125" And I don’t see a tolerance for angles, nor do I see a flatness tolerance. May want to specify minimum base metal thickness too because some of those corners look very over ground and will need built up. Also, you call out fillets at the size on size joints where that should be called out as a flare bevel since its an open root, not a fillet, on 2 sides. Your square frame needs some more weld callouts because you have a groove weld called out (should be CJP i think based on what I see), but I’m pretty sure that you got a PJP fillet on the inside of those corners and underfill on the outside (over ground)
So, kinda got what you drew, dimensionally. Welds are present, but I doubt they’d pass an AWS inspection, either D1.1 or D9.1 visual criteria.
I’m curious if I can beat your local fab guys, get in touch if you want me to bid it.
You don’t stack tolerances. A 1/16 tolerance on twist is not in addition to 1/16 general tolerance on fractional dimensions. It was a call out to make sure to control twist and the total tolerance remains 1/16".
I mean it’s no wonder he would turn off comments if psychopaths like you are the type of people that were posting to his videos. I’m actually surprised he hasn’t just banned your account for being an annoying troll already. I certainly wouldn’t have tolerated such inane nonsense. Aside from that, I don’t see why it matters what level of “seriousness” these shops had. They were given a job, with clearly marked tolerances. And they failed to deliver or even test to see if they met the instructions. The drawings function as part of a contract. This is just like giving instructions to a general contractor on remodeling a kitchen and then they don’t follow through as agreed at all. Weird how so many people would choose to side with a bunch of blurred out contractors giving in essence a “bait and swap” product. Wild.
Yes same to you or whatever. Anyway you can blow the guy all you want but that was a shitty print no matter what you say. And on his rebuttal video he had to use a hydraulic press and a C-clamp to bend his Parts into print after using his own fixture table. And on top of that he didn’t even band saw his miters to the right size; not by a long shot… and he didn’t use nearly the scrutiny on his own parts that he used on the customer’s Parts with the granite table and sliding shims underneath and so on. It was a hack video one after another after another advertising his stupid tables So you can suck one dude.
I would much rather be a psychopath as you say with a genuine opinion based on observation then some loser over-agreeable follower like yourself, giving mindless compliments to a face on the internet in hopes of getting little hearts clicked on your comment lol.
I agree. I advertise and post my fixture table in use. The majority of people don’t even know what it is, so education is a way I elevate the trade and separate myself from other shops.
Wow, is there anything else?
I have a couple of questions for you and I hope I don’t set off the same nerve the other guy did.
If you feel this strongly about the Videos and I take it maybe the forum, why come in here?
I agree using the press was kind of a set up as it was just wide enough for the parts to fit in. On the other hand I always like seeing how people handle problems as it gives me ideas on how I can solve mine.
Everyone sees things differently and you have to accept that. I have table that did not have holes in when I bought it and added them later. Some people on here say you can build anything on a table with out holes in it and I bet they can. But I can tell you I would never go back to a table with out holes, but that’s just me.
There is always stuff to be learned be thankful there are people and forums that share ideas.
And at some point maybe he will turn off posts that really don’t provide much useful information in the forums. Lots not litter up the forum with this petty bickering.
Great video. I love that you’re taking the time, not only to create the video, but to really dig into the topic of industry expectations.
I have experienced something similar. I’m a machinist by trade, but have a background in welding (albeit to a much smaller degree). At any rate, I have been assigned by my company to interview and vet prospective welding applicants.
I interviewed around ten, and while most of them could weld with a good degree of proficiency, all of them failed the print reading portion of the test.
Also, despite my supplying the applicants with measuring tools, all of them ignored squareness. parallelism and perpendicularity callouts, when welding various coupons (mostly 2 and 3F callouts).
I found this to be odd…the assembly needs to have those specifications met…and all these guys were professionals with years of experience.
I thought about this for a while, and came up with an answer, I think…
I think it’s because this level of accuracy is simply uncommon within the industry, so most welders overlook it.
Also, from a manufacturing standpoint, engineers might find it more cost effective to not pay close attention to welding assemblies. Eg; If the assembly has to meet tight tolerances, they might opt for loose tolerances in the weldment prints, and then have the critical features of the assembly machined after it’s been assembled in welding.
The aforementioned might be less expensive, especially in large production runs, than having a welder fixate on tight tolerances on every single assembly.
That was kind of long-winded, but I thought it might offer a little insight into the subject.
For the record, I absolutely agree that proper fixturing is essential, not only in accuracy, but in productivity. It’s way easier and faster to bump an item up against a stop, clamp it, and weld…than it is to fumble around trying to square up each assembly in every possible direction.
Fantastic video! That said…
In my opinion, the issue is obviously that the selected shops simply aren’t serious: they lack the will, equipment, and skill to make an in-spec product.
If I am looking for precision, and the prospective fabricator goes “wow, you’ve got a drawing, cut list, and everything!” then that’s an immediate red flag to get out of there. It tells me much about their usual clientele, who presumably come in with napkin sketches and a vague rambling explanation. A quality fabrication shop is almost always asking questions to figure out exactly what the customer wants and looking for more information like what is actually important to the customer.
If any of these shops had done so, they’d have quickly found out that the customer wants unusually tight tolerances (compared to their usual gigs) and maybe they’d have turned them down or gone into a negotiation about tolerances.
As for why these shops exist?
Generally, “welding” is quite easy. Reaching a level of “generally functional results” in wire MIG is only a couple difficulty steps removed from using a hot glue gun, and while masters can achieve a very high level of skill, the barrier to entry is basically just money for tools, metal, and a bit of can-do attitude. Anyone with even the tiniest smidgen of “building things”-acumen and will to learn can be trained to produce parts like these out-of-spec tables within a week or two.
“Skill issue”
The problem is, like with any craft learned in a hands-on manner, that you eventually run into a “skill issue gap” that can only be solved in a formalized learning environment. You can do thousands of welds and learn quite a bit, but eventually, to progress to the next level of skill, you are gonna have to put your nose into a book, your butt into a classroom seat, or have an instructor with the knowledge teach it to you directly and in a concerted manner.
For example, reading technical drawings is not a skill you can really learn by osmosis. Sure, you can look at a drawing, and get a general idea: they’re made to be self explanatory to a degree, but that will only get you so far. If you want to actually advance your skills, you need to actively pursue learning the theoretical underpinnings of topics like draftsmanship, tolerance, and precision with some degree of academic rigor.
If you don’t do this, you will simply eventually reach a “skill cap” of what jobs you can and can’t do. This is, of course, not necessarily a bad thing. These fab shops clearly have found their niche, are probably profitable, etc. but they are simply overwhelmed when they are approached with a job that has a complexity and tolerance requirement that’s this high.
Well said!
Im a novice welder with ACD, which my instructer said is the best ingrediants for a welder, Im from panamá like in central america not florida.
Well if the main issue is tolerance, my instrructor just ads heat to the weld area, this does not eliminate warp but it does minimize it to a point., hear we use mm so., I have witnesed my instructor with 38 years of experiance hand over work with tolerances almost to 0.021mm close to tolerance., we dont have a fancy welding table but he uses the 2 pipe trick and the Slab of steal trick. i showed him this video and he just went “thats a pain in the ass to make, i have better things to get a headache from…”
Awsome videos - do a chalenge !!!
The answer to your question is the same for any part that fails in any trade or profession; you can have the best equipment, the most know-how, the most experience and skill, and none of that matters if you simply don’t care if it’s right or not.
Not a single one of those fabricators bothered to make the piece right. They were immediately dismissive of the tolerances and difficulty, assuming you would be fine with the imperfections and figured their fabrications would be “good enough” for whatever PRACTICAL purpose you had for them.
For most projects, these men are fine rushing out flawed products to make the most money, and that is the entire issue and answer to the question. It’s hard to find your run-of-the-mill fabricator who hasn’t become complacent.
Hi, i’m not a welder but to my point of view the distortion has to do with the quantity of heat applied per unit of time. i.e.: they made to much weld at the time.
New to the forums, been a fan for a while.
For my 2 cents, it comes down to what several others have said: Knowledge and Tools
From my experience as a machinist who went to get an engineering degree, flatness and perpendicularity are hard concepts for most people to understand. Size and straightness are understood by almost everyone with no prior knowledge, but without the education, formal or otherwise, flatness is a mystery to a lot of people, engineers included.
As for tools, they may know the basics of what the callouts mean, but not know the best ways to measure or qualify them. Or they may not have the right tools.
Flatness callouts require comparison to a known flat reference, such as the surface plate, and cannot be done with just a straightedge and speed square. Perpendicularity is the same. If a shop does not have a precision surface plate or similar tool, they cannot reliably do any job that has a flatness callout at all.
Personally, if I were to get quotes or estimates from any fab shop for anything with any kind of GD&T (geometric dimensioning and tolerancing) like flatness, perpendicularity, cylindricity, concentricity, etc., I ask how they measure and confirm the specs. If they do not have the right inspection tools, they simply cannot do the job, no matter how “easy” it is and how confident they are in their skills.
I just saw your video and subscribed. I hope I am not stating the obvious, but here in the UK Metalshop was disbanded in schools in 1977 and only the few dinosaurs in schools continued with teaching in metal workshop conditions. Fabrics, glues ,and theoretical materials science replaced metal manufacturing in schools. We even closed state technical further education facilities. Skills died.
The precision you adhere to is a wonderful lesson in the correct way to plan and assess a fabrication job. The way you test and examine jobs is exemplary. Fabrication shops in the UK see normal distortions in welded structures as an acceptable reality. Like fruit growers, they accept that all produce will vary within their own convenient limits. The standard of a job is therefore not driven by a set tollerance, but rather by a political standoff at the time the job is paid for and collected.
The standards you display, and the way you demonstrate how heat and distortion conspire against accuracy, is a breath of fresh air in a sewage works of poor training.
Hello,
I “learned” welding from YouTube by myself and a lot of scrap material from the local steels trader. My first successful project was smokeless rocket stove. This is when i experienced my first weld distortion. And it was severe as the iron was thinner.
I also noticed it is difficult to fix and i ended up stretching the material to “Fix” it.
But since it wasn’t really important to be accurate wasn’t an issue.
However i noticed if you weld on dots, giving it a bit time in between dots to cool down, you get much less distortion. But looks uglier and take more time.
Would that help?
part of the issue is here that, you didn’t specify that this frame was for a Very accurate dimension and form shape test. just the simplicity of the frame in appearance would have most fab shops not even look at the required tolerances. and for almost all general purposes of a frame like that, it would still be fine for most applications with double the tolerances. if it would have been mentioned to the fab shops the importance of all tolerances you where looking for, i think there would have been more passes. fab shops need to be made aware of exactly what it is someone is looking for in my experience. mind you, i agree that a lot of them should have a bit more effort and pride in their work. good video to make shops aware 
As a complete non-welder, I would have liked for you to have demonstrated the square tubes were completely straight to start.