Limits and Fits: The ISO System 

Yes

is there no such product?

Oh god I was just going to ask the same thing if these existed! It looks like 2 years later there is still a market for something like this.

​@@oliverwan1520It'd be an easy thing to 3d print, I bet

@@comedyreliefguy5112 3D print tolerance is only really comparable to the same printer with the same settings, and typically the same filament material. Layer lines, thermoplastic cooling shrink, etc., all contribute to how bad 3D printing tolerance actually is; and no, other methods outside of FDM printing aren't much better, they might tighten how out of tolerance their parts are but they all have their own set of problems. Using the same printer, settings, and material means that you end up with all of these variables ending up as a near constant, though it also depends on style of print, such as overall size, surface areas, infill, etc., where the tolerances between print A and print B are acceptable, and this is why 3D printing tolerance is only comparable to itself using identical variables. You also need to measure the parts to determine if tolerance is within given spec, or to at least find what the deviation is if two out-of-tolerance parts otherwise fit well. There's the option to do solid printing with a machining pass for finishing, to bring bad tolerances to widely acceptable tolerances, but you also literally do not see this methodology outside of very niche uses. By the point of doing this, you're better off with just one operation on one machine for less wasted machine time. But by the point of machining something, you're also going to be measuring the tolerances of the parts. Go-no go gauges exist, but how often are you using parts of the same shapes and diameters? The go-no go board that the original comment is suggesting would evolve to be the size of a room throughout all of the projects it would have encompassed. Unless, again as implied earlier, you're only using the _exact_ same shapes and diameters, which is not often unless you're using off-the-shelf parts. The only area where something like this exists is for bolts and nuts, because they're consistent and various areas of the world have widely agreed on systems, and you rarely deviate from those established systems, unfortunately these go-no go sets for bolts and nuts really only exist for common sizes of machine screws, I have yet to see any for any other thread type, where you just have to use calipers and gauges to determine tolerance and two parts to determine fit. And this circles around to how tolerances are actually determined, through actual measurement, rather than a gauge that'll quickly tell you if something fits or not. Given the scope of the issue and how easy it is to just measure things with common machine shop tools, the want to have a slip-on go-no go gauge for everything is just pure laziness, and honestly a waste of time and material; go-no go gauges exist for a very specific reason, and that's to rapidly check quickly reproduced parts in the order of tens to thousands, where measurement by tool becomes a waste of time, but these are typically specific to certain parts, not a general purpose pegboard of seeing what fits nicely. Michael also demonstrates how engineers are entirely white collar, because anyone who spends time in a machine shop will quickly learn what proper fits feel like, literally something an apprentice would learn before starting their blue collar career. This is why 3D printers are commonly a white collar toy, because the people using them clearly do not understand their nuances, or why industrially they're only used for rapid prototyping before actual tooling, with better tolerances, are used, and this rapid prototyping is done within the drafting phases so that there is margin for error that feeds into tweaking the design. This is also why machinists will use calipers and measurements to determine tolerance, two parts and feeler gauges to determine fit, and why they'll whip up a custom go-no go gauge if they need to do this process multiple times within the same project or lineage of product. Picking up a tool and doing it properly really isn't that hard, yet inexperienced white collars seem to either be too lazy to do so and/or have a phobia of touching blue collar tools; it's insane how people look for an 'easier' way when the easiest way is the correct way. A lot of people here clearly have a lot of learning to do, considering the lack of common sense and lack of basic logical thought.

This is the winning comment so far

Is that her at 2:08?

@@TabletopMachineShop ream her out.

So when I hit a bigger number than I’m required I’ll always use a center less grinder

Weld it out and recut

RU-vid actually makes you specify "Is this video for children?" now. I can see I was wise to check "no" :P

I see your 9 year old doesn't have much "tolerance" for such stuff ;-)

@@tspandya I see what you did there.... 😂

Wow thanks!

Me too.

That was a nice compliment you paid that man on his video

There's always a bigger hammer...

I personally like the "beat to fit, paint to match" system which also goes along with "grinder and paint makes me the welder I ain't "

Thanks!

Niiice, free views! Just kidding. Thanks for the advice. There were times I found myself running out of breath, so that might be a good indicator for when to slow down :P

For all the european folk... 0.004 inches is 0.01 centimetres or 1 tenth of a milimeter

​@TabletopMachineShop don't listen to him continue talk with speed so the listeners don't loose attention

I let a lot of giggities go in this one :P. Yeah I've found this helpful. I used to be fairly generous in my estimations on tolerances but this is nice and consistent

If tolerances are the bane of your existence, tolerance stacking is likely to drive you through the roof lol.

@@MFKR696 way ahead of you. On the flip side, I can see the clear starry sky from here!

Thanks Keith!

Good question! The ASME standards (and no doubt their ISO counterparts) indicate that parts should always be measured at 20C. You can design your part to be the right size at its operating temperature (using limits and fits for example) and figure out the size at 20C (where it's going to be machined and inspected) based on the coefficient of thermal expansion

Well, hand finishing can be exceptionally accurate, i guess it's just nice when the parts are interchangeable! Yeah I guess if you're aiming for a 3 micron tolerance and your surface finish is in the 0.8 micron range you're looking at 25% of your tolerance zone being the surface finish. Knowing ISO, there's some way of factoring that in, I just havent read that far yet :P. I'd love to do a video on GD&T with respect to flatness, squareness and parallelism (form and orientation controls) but that is one deep subject and I doubt I could do it justice :P. You make a very good point though; if your parts aren't flat, square, parallel, etc, they can match the print but still won't fit!

Thanks Michael! Are there any parts that you feel I glossed over too quickly?

Tabletop Machine Shop Nope! I just went back and rewatched it twice to make sure I caught all the content. I’d be very interested in a follow up video discussing thread classes and fits. It’s probably quite similar. Great work!

Well... Not all the time, but when you are not sure it's the safest choice :D

Oh oh oh! An electron passing between two parallel charged plates maybe?

Thanks a lot! I'm glad it was a good refresher!

Thanks!

I watched a ton of videos to prepare for this, and so many of them are like "man yelling across room" or "man speaking into microphone from 2mm away" :P

I hear ya, I've definitely spent some time simultaneously heating and hammering things :P

Joke's on you! It's Gloucester MT Extra Condensed! Gotta be consistent :P

@@TabletopMachineShop Oh I meant @9:14 ;D

So? H11 is a lot of allowed tolerance around the hole. Achieving a certain letter is absolutely no problem. The problem is the tolerance (the 11 in your case is way relaxed.. you can carve that with hand tools). Generally 9 is easy, 8 is standard lathe work, drill work, 7 is the same but need more careful touches to creep on dimension, 6 is for the properly tuned lathes/mills/cnc and probably best you can get consistently. 5 is into surface grinding and other fancy process.

Thanks! I used to kind of ballpark "ohhhhhh... 0.002" of interference", but it's great having a standard that produces similar fits consistently

They didn't even teach us this in my degree... They alluded to it in first year with clearances and allowances in drafting and that's it. Sad really..

@@TabletopMachineShop That's weird, what degree is that? I'm a machine shop and CAD teacher in highschool (students age 15-18) and both the general tolerance system (IT tolerances) and the ISO fits and limit system are taught first during mechanics class, and later used in my classes. When I was doing my mechanical engineering studies this system was also thought very early on, since it's so crucial when designing (and drafting) anything that will be send to someone else for manufacturing. One of the major mistakes that both my students and many less practical inclined engineers make in making every tolerance to small. Always use the largest tolerance that will work for a given application. When I was still a machinist, I once worked a week on some parts with tiny tolerances, because the drawing said so (all dimensions to IT2 or something insane like that). When the engineer came to get his parts I asked what they were, and they were door handles. I didn't have to pay for the man hours, but I was still pissed, since it was such a pain to make.

Thanks Justin!

Glad to hear that, thanks!

Nope this is a TMS "keep everything in frame" mat!

Drills don't really make round holes, and that's something reamers help a lot with. I guess theoretically if you have a really rigid setup, really dialed in cutting parameters and a high quality, well ground drill you might be able to get away without one.

Watch it again. It should start making sense by the third time.

Thanks!

Yeah, sometimes as I'm saying these things I can't help but smile lol

grats for being able to keep your voice neutral for most of it, but that first bit you were trying to keep the giggle out of your voice xD

I hear ya! I had to teach this to myself when I got a bunch of numbers and letters thrown at me at my first job! Doing the research for this video also really helped cement the knowledge too

I'm sure there is a standard for audio recording somewhere out there :P