Flatness Tolerance - How to apply and measure

This video shows everything you need to know about flatness tolerance in ASME Y14.5. It includes proper applications and functional uses. It also has demonstrations on how to inspect. Per unit area flatness is also covered.

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#profile tolerance #datum #datum feature #asme #asme Y14.5 #Y14.5
#GD&T #geometric tolerance #Y14.5-2018

[nickp]

Great overview! Very clear demonstrations. Thanks.

[SuperJJ]

Really good explanation, keep up the excellent work!

[mscscambodia]

You need to have the part mounted on three points on the surface plate (gauge or 1-2-3 blocks) for flatness as 3 points make a plane, see GD&T Y14.5-2018 setup processes.

[ajeshgeorge]

Thank you for the video. It's very helpful. Keep posting such contents. Wish you good luck...😉

[thinaung]

It's really great and have a help in my work. Thanks a lot

[ud]

It is my goal to learn GD& but so many caveats and definitions and interpretations makes my head spin. Difficult subject, great video!

[divermike]

Unless I misunderstand flatness is hard to separate from parallelism when inspecting. In fact impossible? One can only minimize the parallel error first then start trying to measure flatness. Correct?

[jasperamsing]

Hey thanks for this explanation!
Question 0:15:
Is there a difference for the manufactured part to inspect if you:
1) Datum A onto the flatness callout itself (like in the video), or if you put:
2) Datum A on directly the surface

Does it matter or is it actually the same?
Thanks :)

[ashow]

Seen scenarios where large plates get stacked directly onto one another and slide/shuffle around during shipping and are left with scratches. Usually parts are still functional even though they would fail a flatness check because of a scratch. How would you specify that indented scratches/gouges are allowable on let's say 5% of the surface as long as the other 95% of the surface is flat within the specified tolerance zone? Add a note on the drawing?

[mahantesh.hindiholi]

Great explanation! Could you also explain the difference between regular flatness and a flatness with CZ? How the tolerance zones would be in these two cases?

[ajtroglio]

Umm...I don't think adding some random size shim under a side @4:40 gets you to correctly measure flatness. All you're doing is adding another unknown 'parallel' surface to the mix. To measure flatness of that part I was taught to turn the surface to be measured upside down and support the part at tool points spaced as far apart as possible to limit their effects, like shown at 6:15. Showing the method at 4:40 I think is misleading but I'd like to hear the reasons why it's not.

[weikinsiew]

Cool height gauge, may I know where you got it?

[adithyaasrinivaas]

in the starting, does flatness of 0.1 means it is controlling Ra(Surface roughness) or Ra is further refinement of flatness. Size->Flatness->Ra ??

[forrestgumpv]

Try that on a 2.0 wide flange that is 333.5 diameter.