GD&T Lesson 4: Datums & Datum Reference Frame

[@cncdude9680]

Thank you for all the great content! I've been watching all of your videos for the last few months as I was promoted from Machinist to CMM Programmer. I always find myself referring back to your videos whenever I have a question. You have helped me more than you know!

[@RDeanOdell]

Hi! Thanks so much! I am trying to create a metrology/CMM “micro-credential” at the college I teach at for the exact situation you have achieved. I’m thrilled my videos have been helpful in your career. Please feel free to send any questions my way via comment or email.

[@MrAkosFintor]

Hey there, I'm a machinist but starting a job in inspection and would like to program CMM's . Wrote some programs in Mastercam as a machinist. How is programming CMM compares to CNC? thanks

[@bobmrcs]

Thank you for making these videos available! I've been a student of GD&T for 40 plus years and appreciate your professionalism and getting your perspective and insight.... Great job!

[@RDeanOdell]

Thanks so much! I really appreciate your feedback. I try to present the material in my own way.

[@alexandersomera9974]

Dude. You are awesome. I was dreading going back and watching a year's worth of metrology courses from college to prep for an interview and you have encapsulated all the most important stuff in a night's worth of content. Thank you for sharing your knowledge and utilizing your pedagogical talents to help people learn 🙏

[@RDeanOdell]

Wow, thanks! Glad my videos were helpful!

[@mikeb1520]

I’ve been binge watching your videos, I’ve learned a ton from them. With your easy going teaching style, you are the Bob Ross of GD&T. I’m half expecting you to say, let’s add a happy position reference over here lol.

[@MrAkosFintor]

Dean, I'm blown away by these videos! Thank you

[@RDeanOdell]

Thanks so much!

[@connorjones7202]

Just adding a comment to make sure you know your video is out here helping people become better. Thank you for your expertise.

[@jephcatacutan2571]

Thank you for what you do Dean! I learned a lot from your videos! keep it up!

[@RDeanOdell]

Great to hear! Thanks so much.

[@palleturu_memories]

Hi Dean, I have a question for you, if you have a triangle part with a hole in the center, so while measuring on CMM how to create the 3 mutually perpendicular planes & how to locate the axis of the hole with the respective to A, B & C Datums?....in this triangle part I took, back face, bottom face and one of the angle side face as datums A,B,C....now how to generate the DRF frame

[@mvinformationalfacts839]

17:04 solution of your problem .provide datum A profile tolerance to 3 faces and datum B to flat mounting surface

[@vor6126]

Amazing video as always Dean, keep up the great uploads !

[@RDeanOdell]

Thanks a ton!

[@brytonheiselt1915]

I feel like more of a genius every new video

[@RDeanOdell]

Great to hear! Thanks so much!

[@AccentonComedy]

Hey, great Lessons, will watch as much videos from this channel as I can throughout this month! Hope this videos will be great jumping board for learning about quality measurement.

[@RDeanOdell]

Glad you like them! Thanks so much, I think I have about 100 videos on GD&T & QC

[@AccentonComedy]

@@RDeanOdell You have more than enough ;)

[@shankar554]

Watched few of your videos.. love it. Keep coming!

[@RDeanOdell]

Thanks so much!

[@martincacer7033]

Great subjet, upgraded, expanded, and give me more vision of GD&T watching your videos. I appreciate your time and dedication.

[@RDeanOdell]

Thanks so much! I always appreciate your comments.

[@richp5060]

I really enjoy learning from your videos. Maybe you could make one on measuring tubes with multiple bends. I always struggle aligning tubing on my CMM with intersection points for XYZ.

[@RDeanOdell]

Thanks so much! In the next few months I will be updating my CMM videos. Can you provide any information on the parts you are measuring?

[@BennettMcIntosh-h9v]

As a student who is confused and has a test tomorrow morning this is amazing help

[@RDeanOdell]

Happy to help, what school are you attending?

[@vythinathanduraiswamy3430]

👍Excellent introductory video on Datums! Very much to the point and very comprehensible. Thank you.

[@akilanm5592]

This stuff give me hope and confidence.Thanks a lot man🙏

[@harwellmejia6465]

Excellent ! Thanks a lot, professor. This is really helpful.

[@mohdsani-m6i]

Explained very neatly and in easy way. Thank you

[@C777-q3w]

Can you make a video over the terminology of which datums control what? For example, if a profile can control location, size, form, and orientation, and a call out has three datums, does the primary datum control the location and orientation, the secondary controls form, and what does the tertiary control? Or if it only had two datums called out, what does it mean to the machinist or manufacturer as to what is "more important" to the designer? Form and orientation and disregard location and size? Thank you for these videos!

[@QwertyCanada]

Thanks, last one about multiple datums frames was a great example! I also got a question about where you talked about the pattern and how we need to use the position instead of perpendicularity for datum B, which makes sense. However how do we tell manufacturer the actual position of the pattern itself (the relative location of holes in the pattern is clear and identified, but how do we specify how much the pattern should be up and down, and do we need another DRF to make that clear to machinist?) Kind of similar question to this is figure 4.9 of 2009 standard, it's not clear where datum B is, again relative positions are specified, but how does machinist know where to drill hole B to begin with, they only know it should be perpendicular to A. Thanks, and sorry for very long question 😅

[@RDeanOdell]

Hi, great question! The short answer is to think of all the of the features being relative to the pattern of holes serving as a datum. Often this is a profile with a wide tolerance for areas that mate to air. Does this help?

[@QwertyCanada]

@@RDeanOdell Yes! I Guess my conventional tolerancing mind was so used to drawings with part outside edges as datum; it makes sense now, thanks!

[@michaelgrant9784]

Is there a difference between placing the datum on the dimension as opposed to on a surface on a cylindrical part? Is the datum an axis in both cases? API 6A shows the datum on the flange bore, but all the examples in ASME Y14.5 have the datum attached to the dimension. I expect it has the same meaning and this is just a matter of not enough space on the drawing as I can't think how else to constrain the part for inspection.

[@eartheartbaratheon791]

14:00 does the MMC need to be applied always when we're specifing a geometric tolerance to a FOS? And if not, how does it change the message?

[@MOHAMADFIRDAUS-l1d]

I have a question that can be datum located at id dimensioning, for hollow tube thanks.

[@mathewjadamec4868]

12:45? A flatness on a feature of size? This seems more like an application for straightness. How do I inspect the flatness as you've drawn? Thanks

[@shankar554]

In the last example you gave will it be alright to have open dim B/W datum B & D along with removing the profile control frame for datum D surface?

[@alanchang0118]

Thanks for your clear explanation. I think datum reference frame is the most important chapter in GD&T. I have a question about setting hole pattern as datum. As you mentioned, the measurement origin is the center of those four holes. How can I determine the orientation of this Datum Reference Frame on CMM? Can I choose any one of these holes for alignment?

[@joshgworks]

Great video, this is super useful to bringing beginners up to speed.

[@RDeanOdell]

Great to hear! Thanks!

[@hann9630]

Thanks for your great videos! I have a question: At the pattern example the A datum confuses me, how can it be used for position of the hole pattern if A datum is the flat base as shown on your board?

[@janardhanduda9224]

Great explanation,Thank you so much. Please make more videos on gd&t.

[@RDeanOdell]

Thank you! I am working on more videos presently.

[@nekomatajs]

Great info .Could you do one on measuring perpendicularity? Thanks

[@RDeanOdell]

Hi, I actually have a video about that already: GD&T Inspection: Flatness, Parallelism and Profile kzbin.info/www/bejne/eaGnhmqEl9CgeLs

[@anncharlottemurigi1397]

At @22:15, can we say datum B is an axis at the center of the part or datum B is a mid plane in the indicated hole

[@tomascancelliere4348]

I'm a bit confused. In a different datum video, you said we can't use flatness as a datum feature of size, but in this one, it is shown as an example for the middle depiction. Am I misinterpeting something? Or is there a rule that allows it?

[@RDeanOdell]

Hi, it the other video I was showing ways to apply datum feature symbols to indicate the datum is a surface. A flatness applied to a DMP can be used as a datum, but it is not common. It is not ideal as a primary datum, it is difficult to simulate.

[@tomascancelliere4348]

Thanks! Your videos are a great source of knowledge. Thank you for all your insight and explanations!!

[@nikunjkumarbhatt5904]

Thank you very much for your contribution for the betterment of industry.

[@RDeanOdell]

Thank you so much!

[@learnthrivecompassion422]

Is GD&T required for CAD product design? At what stage of product design would GD&T be most useful?

[@RDeanOdell]

Hi, it’s not required. Some companies don’t use it at all. The thing is, the companies that do use it make it very important. It is used during the early design process in modeling parts, then in the drawing phase to document the design intent.

[@learnthrivecompassion422]

The drawing phase is not preceeded by the modeling parts phase? And by modeling parts, are you referring to creating them in a CAD program typically? I ask because I want to get into product , part design in CAD, particularly Solidworks but I want to approach learning the skill methodically and systemically without jumping ahead.

[@Dybeeel]

What if I put Symbol at cylindrical surface, but not in line with dimension line? Is it even legal? And if yes, how to interpretate it? :)

[@MukeshRajasekar]

Thankyou so much enjoyed the session throughout

[@pochtronvirelune25]

Always the perfect content! Thanks a lot

[@RDeanOdell]

You’re very welcome, thanks for watching & commenting!

[@shankar554]

Suggested topic from my side for your future videos...Let us say I have a rectangular part with a large 45 deg chamfer on one edge through which a hole is drilled. If that 45 deg(45 deg to horizontal) surface becomes my primary datum for the hole then how will my cartesian co-ordinates change & how will the basic dimension be used to locate the hole etc. Please amuse me by answering this Q.

[@shankar554]

Please do not ask me to put basic angle B/W axis of datum & the horizontal plane & provide angular geometric tolerance. I want to make sure that the chamfered surface is my primary datum for the hole so that I can ensure that hole is perpendicular to this surface.

[@RDeanOdell]

Hi, I would make that chamfer surface the primary datum for whatever features exist there. So you would need more than one DRF. I’ll see what I can do about a video covering multiple DRFs.

[@shankar554]

@@RDeanOdell Thank you. Will look forward for the video.

[@shankar554]

@@RDeanOdell Great! After u make the chamfered surface as your primary datum could you please locate the feature on that surface with basic dimensions. Asking this as once primary datum is set the secondary & tertiary datums are at 90 degree to it. And we provide basic dim from datums and not datum features. Please show with an example if possible.

[@shishirmahmood1766]

Great work Sir!

[@godspeed1148]

Can we call a datum to dimension of a hole directly.(so that the axis of the hole is the datum)

[@RDeanOdell]

Hi, Yes, an internal or external cylinder can be a datum feature. The axis of the actual mating envelope is the datum axis.

[@godspeed1148]

Thank you and please make the video on position tolerance....

[@amolaegade5428]

Dear sir I also want to gain knowledge like you in the field of GD&T and become like you.....what should I do to achieve that?

[@hemendrasharnagat5534]

Hello Sir, I have Some questions, could you please clarify it. 1. Can it is compulsory to Show secondary and Territory Datum ? when we use to show Primary Datum ? 2. Can it is compulsory to show Feature Control Frame with Datums ? 3. Why we use Datum? can tolerance on dimension only can work ? 4. The Difference of AMSE vs ISO Standard for GD&T looking forward to hear from you. Thank you!

[@RDeanOdell]

Hi, thanks for your question. I ask that you watch this video first, and then let me know if there are still areas you are unclear about. Applying GD&T: 3 Basic Steps kzbin.info/www/bejne/gpukdHeNobOgZpY

[@charitharanwala]

How datum B became a center plane at @5.46 , it just the other surface ?

[@charitharanwala]

he explained it later.@ 10.48

[@davidraj_2129]

Great explanation sir..Thank u

[@RDeanOdell]

Thanks so much!

[@a.c.estudio2432]

nice sir, thanks for the knowledge 👍

[@RDeanOdell]

Thanks for watching!

[@nicodeusvillafranca8051]

This is really helpful

[@jamestrank5928]

4:02 You didnt draw it on the wrong side. You position the piece backwards

[@ronconovoa7566]

so much info here thank you

[@RDeanOdell]

Welcome!

[@Pkstoic]

Very nice sir

[@RDeanOdell]

Thank you!

[@a.c.estudio2432]

thanks again Dr

[@RDeanOdell]

Thanks so much!

[@aniketshelke8796]

Your voice is same as in the max payne game

[@kalimuthuselvaraj8836]

❤

[@itziksh3272]

Nice !

[@RDeanOdell]

Thanks!

[@anthonybailey6594]

Thanks for the info.

[@RDeanOdell]

Thank you for watching!

[@mustafahayriatl2723]

niceeee

[@ryaneb1370]

I'm still so confused. I hate adhd.

[@siljoshajan5850]

chooper

[@mattadams5541]

Your practice part is from the Israeli Iron Dome. 😎