@Fireball_Jason The 20 1/4" callout and measurement can be true even if the 90deg callout is 89/91 if that is what you were referring to.
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I donât believe itâs necessary. The plans are clearly labeled 90, that means 1/16 in any direction gives you the value of 1/8â. 15â high and a 1/16 distance in any direction off of 90.
Hi Firetool.
I really enjoy your videos, they are very educationalđ
A thought, in relation to the task, which clearly shows that all 3 fail.
Would it be an idea to invite them to your workshop and show them how they fail and what they can do to correct/get betterđ
i.e. constructive criticism.
Have a phrase that I love to use.
If you are not made aware that you have made a mistake, you can do nothing to correct the mistake (redo it if necessary) I am of the belief that everyone has the right/claim to be told if they have done something that does not live up to what is required!! so they get a fair chance to change it. It is really easy to criticize people for not being able to deliver the right product. And can destroy peopleâs businesses. (I am not thinking here of repeated mistakes about the same subject)
Regards Jesper
Denmark
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The problem is one of human nature, they have been making parts that are not to spec for years. I bet if you asked them they have never been pulled up on what they have been fabricating as not good enough/up to spec ever, so they just carry on until it becomes a problem. To charge $170 an hour to not produce to spec is âgetting away with itâ I also bet that if the ones that said they would fix any âproblemsâ were called on it when they realized they could not actually do the job needed would just give you a full refund to go away. Until customers complain often about out-of-spec builds they wonât be buying anything needed to produce that spec.
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@Fireball_Jason Think of it this way, you essentially have two square planes stacked 15" apart. Assume both planes can be dead nuts 20x20.25". Because you have no angular tolerance on your 90deg callouts nor perpendicular GD&T Symbols your table can look like a parallelogram looking at it from both drawing views on the right side of the drawing and still satisfy the print. No shop can pull a tape measure between the outside corners of the top plane and bottom plane without a CMM machine. so you are relying on that 90deg callout. Which in my experience as shown would be interpreted as +/-1deg. and that doesnât even factor in the two 20x20.25 âsquareâ planes not being square, to that same +/- 1deg that i assumed.
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So, your video basically just confirmed that none of the fabricators take the job seriously. They donât even know if itâs flat or things are the correct length. Theyâre just hoping and doing very basic sanity checks, without attempting to get to any level of precision.
So yes, these tests arenât good because itâs clear they donât actually care to try to be precise, and you canât compare âIâm using a fixture table and trying to be as precise as possibleâ to âIâm not using a fixture table and I donât really care about this projectâ.
The only real way to compare the two is the impress the actual importance of precision on them, which just handing them a drawing clearly isnât doing. If someone else wanted a precise part, and was delivered what those guys gave you, theyâd not pay, and something tells me those guys having a fixture table wouldnât change that at all. It doesnât matter what tools you have if you donât care about the job.
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Explicitly call out the tolerances that you need to them in person. I know that you shouldnât have to, but if you mention the considerations such as twist, flatness, warping - Do they then manage to work to the required tolerances? It would be interesting to see if they then charge more for this.
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Iâd like to see you ask another generic fabrication company who does have a fixture table, Iâd be curious if they take the job seriously or not despite having the fixture table. Do they get complacent?
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15 minutes labor?
Will you be doing a video showing a fixture table solving the weld distortion from the âlegsâ?
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The only real way to compare the two is the impress the actual importance of precision on them, which just handing them a drawing clearly isnât doing. If someone else wanted a precise part, and was delivered what those guys gave you, theyâd not pay, and something tells me those guys having a fixture table wouldnât change that at all. It doesnât matter what tools you have if you donât care about the job.
If a customer provides a detailed specification and I accept the job (and their deposit!) then I have agreed to meet the terms of the contract (aka the specification). It is not the customerâs responsibility to impress on me the importance of doing the job correctly.
If anything you could say that this video is testing the skill and craftsmanship of these particular welders more so then the need to use a fixture table. However, between the two videos we now have 6 welders who have failed the tasks.
Perhaps for the next video there should be an open call for welders who specifically want to demonstrate an effective and timely welding process that doesnât require a fixture table.
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Great video, even as I cringed during the fabricator interviews. The quote filling my head during the entire video was Dirty Harryâs âA manâs GOT to know his limitations.â
During your demonstrations, you mentioned welding the verticals away from the seams to reduce stresses. Some of the shots of the tables showed the seams oriented every which way; is this another âYikes!â, irrelevant, or actually a good thing?
Other commenters have suggested challenging other fabs that use fixture tables, and I heartily agree. However, I wouldâve also liked to see you do the challenge yourself on your plate table (since all your target fabricators used plate tables) and give the results to Cesarâs CMM. This should help isolate the ability/care component and get a better grasp of the time/effort/cost required to succeed, or at least how closely you can expect to fail. Then repeat with the full-fat fixture table process to demonstrate the savings and profit proposition.
Iâm thinking it would help them to understand the seriousness of your project by explaining your need for such precision.
Make up something to tell them⌠Itâs a gyro disgronificator base to measure the cellular parallelity of dilithium crystals.
I bet they all assume it was for a table with a glass top and rubber cushions like the first guy said.
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I like this series, but I think you are being unrealistic with the level of quality expected with the shops you are visiting. As mentioned previously you do not bring your Italian sports car to the corner garage to be worked on. I think it should be stressed when quoting that the tolerances are tight and if they can achieve them, not just relying on handing them a drawing. Frequently I see draftsmen that have unrealistic tolerances because they have no actual hands on experience. The shops you are visiting however should be asking you if you really need those tolerances and if in their capability explain its going to be a significant expense to set up fixturing, mitigate warp, etc.
The biggest negative you have against you, which from a quality perspective shouldnât even be a concern, but it is, is a very small job, from a walk in customer. Human nature is the issue here. Most ârealâ shops I know dont even entertain walk in work, its just not worth their time for a onesie from someone they will never see again, balk at the price in the end, and maybe will never even show up to pay when the work is complete.
I would like to see more testing with shops that actually have the capability to achieve this and how they perform. Fixture tables are nothing new, it would be interesting to see if someone with an old school platen like an Acorn could compete with accuracy and set up time vs a Fireball.
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Alright 45. All the measurements and cuts were given to them. It was a fast job
If you do the test again add one shop with a fixture table, see if the issue is lack of tools or industry wide. Also for a real control, add a machinist whose word revolves around tolerances.
Hi! Iâm absolutely not a professional fabricator, but because of the lack of full training I have a tendency to think outside of the ânormalâ box for solutions to problems.
My main go-to for making things as accurate as I can without âproperâ tools is to reference everything off of the base unit itself.
For this I wouldnât rely on a table to keep things flat; Iâd get another piece of tubing and clamp the individual parts to that before a weld to keep 'em in reference to each other.
I didnât consider the weld distortion, though; Iâd probably try to pre-heat the pieces beforehand to combat that. I donât know how well itâd work, though. Thereâs another option of, if a distortion is found, to put some weld on the reverse, and then grind it off. Itâd add internal stress, but the tolerances would be good.
And for small tweaks I like to clamp where the problem is, and apply pressure in a manner that doesnât affect anything I donât want it to. (I may have screwed some stuff up before finding that outâŚ)
I kinda want to grab my crappy 120v flux-core MIG and give this a try some time, see how bad I screw it up. Heh.
It is when youâre hiring Jimbo, who welds PTO acceptance shafts that donât ever require precision or something, and clearly doesnât care about the job unless someone complains.
You say itâs just these craftsmen, but heâs gone to 6 different ones now, all of which fail at the very basic level of caring. Itâs becoming clear itâs probably endemic.
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I think the real reason these are made out of spec is that these type of fabricators are never asked to build within these tolerances, they have never actually measured what their capabilities are. These projects seem so basic to them that they donât take it seriously. I bet if you told them that you would pay $1000 if they meet qc or $0 if they would do a better job, or turn the work away.
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This video mostly reveals that dealing with distortion causes by heat is difficult to overcome. I donât believe it was of any significance but the print does have several errors. If no tolerance is defined for angles they should be in parenthesis and treated as reference. I believe the weld symbols are also incorrect⌠the symbol details should be on the bottom side of the line (the top side of the line defines weld requirements on the side opposite of the arrow). I find most drafters/ engineers do not use weld symbols correctly and many welders do not know how to interpret them.
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Is it a âproblematic epidemicâ if the fabricators never have their work rejected? 99% of the time they are getting away with it. So is the customer A: not noticing itâs out of spec B:Never needed that high spec in the first place. C: making the out-of-spec part work with modifications.
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