GD&T Inspection: Which Features to Inspect First?

I cover inspecting several GD&T characteristics, as well as threads.

[@rodin4429]

I've only recently bumped into your videos. They are great! Wow, you're so clear and get everything across. I've been working most of my life on the far side of all this - the conceptual, development side ie. someone else has to make the production work! - but of course the whole cascade of operations to realise these things is never out of my mind. Really liking your posts :-)

[@RDeanOdell]

Thanks so much! I try my best to explain things instead of rattling off PowerPoint slides or reading from a textbook. I have some experience in both fields, I’d say I prefer the design side, but knowing some basics of manufacturing and inspection is definitely useful.

[@chrissherkel9437]

Dean - great job as always. I really liked your comment regarding the use of MMC on threads. When applying Position to a mating clearance hole and calculating the amount of Position that can be applied (shared) between both drawings (based on the Fixed Fastener Formula), I have always felt that it's a waste to use some of that bonus on the threaded hole. Also, I believe that the tolerance zone applies for the entire thickness of the part, so when checking with the gage pin, I feel that you should also move away from the surface of the part equal to the thickness of the part (really a perpendicularity check). Thanks again for the time that you devote to helping all of us with GD&T!!

[@AndreasAinalidis]

Thank you so much Dean for you video! Just a small correction for the Y value of the thread hole. At 15:10 you measure 0.6995 an later at the excel sheet this value is 0.6895 (17:14). With the true measurement we get, for the Y axis, 0.5425 which is out of tolerance.

[@ABIDEreciNAMde]

Excelent this video, and all other from you mr. Odell , thanks and keep going

[@RDeanOdell]

Thanks for watching and commenting!

[@flawns]

so practical and so easily taught. Thank you!!!

[@RDeanOdell]

Thanks so much! Great to hear!

[@pauldiaz4273]

Hi R. Dean, can you make a video demonstrating how you calculate the findings in excel? Love your videos I’m learning so much 👍🏽

[@RDeanOdell]

Hi, I actually have a video on that topic! I put the link below. GD&T Position Calculator In Excel kzbin.info/www/bejne/np7MlJljjqirnKM

[@logansmith1034]

Hey Dean, Great videos, Question? When you were to report that measurement of profile of surface from F-G was off by .010, would you just report that? Stating " Profile of surface of F-G is off by .010"? Just curious trying to learn. Thank you!

[@richp5060]

I feel guilty by having the CMM to do my measurements. Great Vids

[@RDeanOdell]

Thanks! I think the instant feedback a CMM provides is reassuring. Plate work can be very mysterious.

[@lolcatcatlols]

@@RDeanOdell Absolutely. But understanding what you demonstrate in this video helps to prove out the CMM program. A lot of machinists will argue against a CMM unless you can prove the result with an indicator. :) Good video!

[@alanzhang9068]

Really useful video. Profile inspection is quite clear . I have a question about the positions. How to choose the proper pin size to do inspection like the video ?

[@RDeanOdell]

Thanks so much! The gage pin is used for two things, 1. To find the unrelated actual mating envelope of the hole in order to simulate the axis of the hole. 2. The size of the pin is the unrelated measured mating envelope that is equal to the MMC size. The proper pin size is the largest pin that can fit within the hole, to make contact with the high points.

[@GoDHephaestus]

It was a great video. Can you please tell me the name of the books behind you?

[@RDeanOdell]

Hi, thanks! In this video I talk about my primary reference books: GD&T Books for Students, Engineers, Drafters and Inspectors. kzbin.info/www/bejne/iZWqhJh6YrCDncU

[@charlietripi]

Hi Dean! Question for you: When you were sweeping Datum B for the perpendicularity requirement, it's only referenced against datum A. Wouldn't that mean that you would be sweeping along the shorter end of the plate to check? Not across the longest surface? I saw you did hit all 4 corners, but I have no "proper" GD&T training yet so I wanted to make sure that's the case. Cheers, love the videos man!

[@RDeanOdell]

Thanks for the question! In this drawing, Datum B is the long surface, so I have to sweep that surface to verify it is perpendicular to Datum A. The short side is Datum C, that side is checked when constrained to Datum A & B.

[@estepans]

Hi Dean, this is not what he meant. He meant that you still would sweep the Datum B, but the direction of sweeping is not parallel to A (longitudinally) but perpendicular to A (laterally). Because the perpendicularity deviation would actually take place in this direction.

[@andrepicon6138]

Hello, congratulations for the nice video! Just one doubt, the position tolerance has a cylindrical tolerance zone. When you measure it, I understand you just got a point and checked if it's inside the tolerance zone as a cycle. How do you check if the central axis isn't with an inclination? In other words, how do you measure it considering the cylindrical tolerance zone? Many thanks in advance :)

[@marktrotter6930]

With a Ø.014 true position tolerance zone, you would only have ±.007 on the diagonals. IN X and Y you have ±.005.

[@BillyK79]

For reporting a profile like that one that was off . 012 in Y, you would report. 024 Profile, since you double your worse Correct? @9:30 minute.

[@RDeanOdell]

Hi, yes. The indicator reading that is furthest from the basic dimension (set in the height gage) in either direction will be doubled to report the profile.

[@BillyK79]

@@RDeanOdell awesome! Thank you for the great content!

[@RDeanOdell]

@@BillyK79 You’re very welcome! Thanks for watching & engaging with the content.

[@deadawake123]

on 17:04 "Measured Value Y" should be 0.6995 . Not 0.6895 ...

[@ariel59864470]

🏆

[@user-lj8xp2yq6b]

Specify the goal and need money