For other videos on engineering and manufacturing subjects: Strength of Materials: ua-cam.com/play/PLAXJqmuqGEr7QjsVVyl5jFY6HQTqw6Bfq.html Metal Casting: ua-cam.com/play/PLAXJqmuqGEr4wiY6xroSK67CXeTu0Otmk.html Quality: ua-cam.com/play/PLAXJqmuqGEr4LQvNzKHGO9l00gEN4gmSP.html Design: ua-cam.com/play/PLAXJqmuqGEr706zgRtnwgQiFC5FYLvaTr.html Automation: ua-cam.com/play/PLAXJqmuqGEr6O_nQ-n08qmrtNnAUruj3b.html Calculus: ua-cam.com/play/PLAXJqmuqGEr7Ayo18H7tknyQAJu1OcoUW.html
Explanation is good. But its 2018 you should always show a live inspection vs alot of taking. Do a live video checking tru pos of that hole instead of talking. Talk less show more.
@@TeW33zy Comment is good. But its 2022 you should always talk with an appropriate attitude vs being condescending. Be more polite instead of commanding. Rude less kind more.
3-2-1 had me scratching my head! I've been so used to CAD doing my constraints, I always assumed that I would never need to specify part orientation. I spent a few minutes confused by the datums but it finally sunk in: A references the back plane, which 3 points don't particularly matter. B References a (single) line along the top of the part, and C is any point along the right side. This opens up a better way to not just describe and manufacture my parts, but also the documentation/use of assembly jigs and part handling, thank you!
Doc, no matter how many tines I watch this same video, I continue to get value from it. Thank you sir, had you would have been my instructor back when I was undergraduate and graduate school I probably would have gotten my PHd.
Your videos are excellent. I'm a Canadian Mechatronic Systems Engineering student reviewing GD&T, and you did a much better job in 22 minutes than my profs did in hours. Please continue to make more GD&T videos!
This is awesome, please keep making these videos. There aren't any good GD&T resources on the net and you're doing a great job of conveying the information.
No problem. Definitely got a lot out of it and I would love to see more. I've been struggling with setting up datums, especially when the important features are holes and are angled to one another. There doesn't seem to be enough info out there on using holes as datum features which is crazy considering how many things bolt together. It's far less common for me to want to use 3 surfaces as my datums. Anyway, keep up the good work!
I love your videos! Your delivery of the material is crystal clear which makes it relatively easy to understand the concepts. Please, please, please post more GD&T and engineering drawing videos. I'm struggling at work understanding engineering drawings and GD&T. Thanks!
Hi Sherri, I'm glad that my videos are helpful. Its people like you why I started this channel. I am planning to put up more videos, but the best way to make sure that you're not missing anything is to visit my new website www.theengineersreference.com/ You can get all of my updates and I will also start making my slides available to my subs.
You are more complete than my professors were 30 years ago. They spent an entire 30 minutes on the subject. I learned most of it on the job. I had to teach this to my daughters because her profs didn't mention it.
Good Job with the 12-modes of motion or the 6-degrees of freedom...DATUMS are the key to any tooling set-up. Thanks! Thomas J. Vanderloop, Author, Technology Instructor & Manufacturing Contractor, CMfgE & LSME
i mocked up my resume to get an inspecting job..and it worked...now I'm going into this job not really knowing anything until i watched this..definately needed the 3,2,1, rule
Hi, thanks for this video that you have put together. I have a few questions for you regarding it if you don't mind - I know little about machining and my questions might be a bit basic: 1. Why would the basic dimension of 16 not be measured from B, as B would be a sure reference to measure from? Why would basic dimension of 34 not be measured from C, as C would be a sure reference to measure from? 2. What importance in terms of tolerance would 10 play, it doesn't seem to have any mention? The surface that it is measured from might be rough and inaccurate when compared to the other official Datum sides (AB & C). Is it not important as to the position of the hole set (the two holes) in relation to the boundaries of the rectangular block it goes through - maybe that block doesn't need to mate up with an adjacent component accurately, but just for it to be attached using bolts? 3. The slide with the 3-2-1 Rule at time 10:02 for example, shows the Right Hand Rule and the 6-axes of freedom. The axes don't coincide in those diagrams (although I can mentally rotate them and see what's going on)...generally speaking, the z-axis is the vertical axis (elevation view) isn't it - thought I would mention this as I think most machine set ups would be with the z-axis vertical (is this the case in industry standards)? Additionally, I know this might not matter, but do you have a preference to which axis has the 3, which has the 2 and which has the 1 restrictions for movement? 4. Why is the term 'counterpart' used, what does this mean in this context - I would imagine it means equivalent part? 5. At time 14:51 it shows the ABC Datums in the control frame and you mentioned that A-Primary, B-Secondary and C-Tertiary need to go in that order and that set up, so even though, some other arrangement of the stops to hold the part in place on the machine would ensure it does not move and all freedoms of movement have been stopped, why would this order be important? Is it related to axis preference or some other preference? AB&C would all be trued up and equally suitable for datums (or are they not?) - is it to do with their specific machining tolerances? 6. The (2x) indicates the two holes I would expect. 7. To achieve a diameter accuracy of 0.001 for example instead of the 0.06 for the holes, would this mean using a more accurate drill bit/chuck/more expensive machine in practical terms - which would make the manufacturing of the part a lot more expensive? Thanks for your help. Kind regards. David.
Even though the 3-2-1 rule is common for establishing a coordinate system, it does not satisfy ASME 14.5 for a DRF. In your example, you would need to use 3 perpendicular planes. Datum A feature would locate on the 3 highest points, Datum B feature would locate against the 2 highest points and Datum C feature would locate against the single highest point on that surface.
A couple more points: 1) when Inspecting the part, you must hold the part against the B and C points. It's like putting the part in a vise using only the fixed jaw and a stop, without clamping it between the two jaws. 2) ANSI and ISO standards suggest that the arrows from the feature control frame point to the center of the hole, and not to some place off the outline of the hole. GD&T is about details. The (2x) below the frame makes me wonder why another box was not included in front of the feature control frame to indicate the number of times. Or maybe a break in the leader line would work. That 2X is important. I usually put mine above the left hand box (and ANSI wants 2X not 2x. This is from the drawing board era, where no lower case were allowed like they are now.) and since the information is essential, not a parenthetical suggestion, no parentheses are needed or wanted.
Good explanation. The only comment I have is your orthographic projection is 1st angle projection. North America 3rd angle projection is most commonly used.
I just didnt undersstand. With respect to datum A, how would I inspect the tolerance? actually that's something I want to know. How would I inspect that part if I had to measure it?
First off, I'd like to thank you for making such an informative video! Could you please elaborate on the 3-2-1 rule a bit? Isn't the block still capable of moving along the "+" directions of all of the 3 axes? I mean, fixture 1 stops the block from moving along the "-" direction of the Y axis, but it can still slide in the "+" direction, right?
@Infinty MFG First of all great video! Thanks a lot for your effort in making this video. I have only one question, why does it matter in what order I write down the datums. For example how to change the GD&T if I were to write down BAC and not ABC?
[Nephew of Ida] I guess this was the most important video of my live. Looking now for part 2. I am more 3D modeler and nobody complained about my drawings. Randomly luck. Because the professor on the training confused me with his explanation of the 3-2-1 rule. Thanks for the video.
Good basic knowledge but can you please provide some knowledge regarding datums in relation to net pads resting, 4 way and 2 way for stamping perspectives
such a awesome explanation .. really I learned something what I need. But i have a doubt like . How profile tolerance get effect by MMC ?? I have seen in some blue prints asking profile with MMC !! seeking for your answer.
Hi Raghu, Thanks for watching and commenting. There are two modifiers that use the same symbol, 'Maximum Material Condition' and 'Maximum Material Boundary'; they use the symbol of an upper case 'M' in a circle. A profile tolerance is subject to MMB, this means that a surface is being treated as a boundary or datum feature (secondary or tertiary). This gives information to the engineer on how to design the gauge (datum simulator) so that the maximum material is accounted for. You can get more information on this from "Ultimate GD&T Pocket Guide" - 2nd edition on page 38.
Hi Professor Cummings at minute seven you talk about the 321 rule and you have 3A, 3B, 3C. you seem to refer to them as three datum planes…when actually they are the same datum planes… so why would you call them ABC when they’re all co planer?
How come the dimensions do not start from datum planes? They're all from the opposite plane. Don't all dimensions have to originate from or be traceable to datums?
WHY are None of the dimensions given in relation to Any Datem?? The "A" has no relevance to the hole position, the "10" is on the far side from the "C" and the "16" is on the far side from the "B". Makes no sense to me.
First thing, that most of the information for that part is left off. I assume that was done to leave only the symbols that the Prof. wanted to focus on. My understanding of how "A" applies to the hole position, is that because the hole is actually 3 dimensional (a cylinder), the axis of the cylinder is to be perpendicular to plane "A". It made no sense to me until I got away from the idea that the view was a 2 dimensional drawing.
Edd is spot on. Terrible example "Professor" shame on you for adding to the confusion of GD&T. The primary "A" datum controls perpendicularity of the holes (cylinders), the "10" and "16" should be located from the datums B & C (or the datums need to be on the opposite sides where the dimensions are located from). it's fine that the "10" is not "Basic" and therefore it would be the drawing block tolerance which would apply not the positional tolerance, but for this basic lesson it probably should have all been basic dimensions located from their respective GD&T datums. It then would have been a worthwhile lesson . In the real world as presented it would force a call to the engineer and drawing change.
The control frame and the order of the datums show you the priority of the different datums as well as how the features relate to each each datum. This will inform the operator/inspector how to restrain the part.
Datum Scheme is simple. Typically A|B|C = X|Y|Z X= FORE/AFT Y= CROSSCAR AND Z = ZED(UP/DOWN). Understand this first along with this video and you will get very basic knowledge. The fun stuff comes with datum targets, local alignments, and theoretical datum assignment for parts that are NOT round, flat, or square for example: an airplane blade or a shaving razor. Its called Curve.
Hi Subdash, You're very observant, the drawing is not perfect, but my hope that there is enough information to help people to understand how the datums are applied to the control frame.
I have such doubts too. For example in the control frame, when tolerance is mentioned and later 3 datums are shown, doesn't it mean the tolerance is for the dimension w.r.t. the three datums? Sorry if I sound foolish. I''m learning
One other thing that minute 951 you said that putting the part on the three points eliminates the ability to go up and down it actually only illuminates the possibility of going down you can still go up, so could you explain that please
Sir ,the datums A , B, C are planar surfaces of the equipment.which has to be used for simulation.The points 3, 2,1 are the minimum ponits of contacts which the part shall have when it sets up on the inspection ot manufacturing equipment .This is what you are saying or I am wrong?thanks.
Very clear and informative. Would you suggest any textbook(s) for GD&T (whether one of the 3 in amazon's top 30 in Drafting and Mechanical Drawing or some other)?
is it always necessary to set the part for machining w.r.t datums because sometimes for example in case of a bearing journal and shoulder we machine them together while holding some other features but in drawings we still give perpendicularity for shoulder wrt the journal, probably a similar video for parts like a casing with bearing could solve my doubt.
Amazing why cant you be my professor mines suck do you teach at any cuny schools in ny like the way you teach is so intresting catches my attention and goes straight to the point
Infinity MFG thank you so much we need more professors like you can you do more videos on this topic showing more tolerance and dimensioning and charts and explain tbe signs like for ex the m or L and stuff like that and practice problems would be nice
very helpful video, but i wanna know the practical use of gd&t. plz share a kind of video in which i can learn gd&t practically through engineering drawings.
That's a good idea. I wanted to lay a foundation of the basic rules and then add to the series by apply it to a practical example. thanks for watching and the feedback!
For other videos on engineering and manufacturing subjects:
Strength of Materials: ua-cam.com/play/PLAXJqmuqGEr7QjsVVyl5jFY6HQTqw6Bfq.html
Metal Casting: ua-cam.com/play/PLAXJqmuqGEr4wiY6xroSK67CXeTu0Otmk.html
Quality: ua-cam.com/play/PLAXJqmuqGEr4LQvNzKHGO9l00gEN4gmSP.html
Design: ua-cam.com/play/PLAXJqmuqGEr706zgRtnwgQiFC5FYLvaTr.html
Automation: ua-cam.com/play/PLAXJqmuqGEr6O_nQ-n08qmrtNnAUruj3b.html
Calculus: ua-cam.com/play/PLAXJqmuqGEr7Ayo18H7tknyQAJu1OcoUW.html
Explanation is good. But its 2018 you should always show a live inspection vs alot of taking. Do a live video checking tru pos of that hole instead of talking. Talk less show more.
@@TeW33zy Comment is good. But its 2022 you should always talk with an appropriate attitude vs being condescending. Be more polite instead of commanding. Rude less kind more.
One of the best, easy to understand descriptions I have ever seen! Thank you!
Thanks for watching!
This presentation on basic GD and T is great. The explanations are so clear, thank you so much
3-2-1 had me scratching my head! I've been so used to CAD doing my constraints, I always assumed that I would never need to specify part orientation. I spent a few minutes confused by the datums but it finally sunk in: A references the back plane, which 3 points don't particularly matter. B References a (single) line along the top of the part, and C is any point along the right side.
This opens up a better way to not just describe and manufacture my parts, but also the documentation/use of assembly jigs and part handling, thank you!
That's awesome!! Thanks for watching and the comment. I like that this video made something clear for you.
Doc, no matter how many tines I watch this same video, I continue to get value from it.
Thank you sir, had you would have been my instructor back when I was undergraduate and graduate school I probably would have gotten my PHd.
Thanks. Comments like this are very motivational.
Your videos are excellent. I'm a Canadian Mechatronic Systems Engineering student reviewing GD&T, and you did a much better job in 22 minutes than my profs did in hours.
Please continue to make more GD&T videos!
Thanks! I appreciate the feedback!
This is awesome, please keep making these videos. There aren't any good GD&T resources on the net and you're doing a great job of conveying the information.
Thanks a lot Mike Walling. Its great knowing that people are getting something out of these videos. Don't forget to share this video.
No problem. Definitely got a lot out of it and I would love to see more. I've been struggling with setting up datums, especially when the important features are holes and are angled to one another. There doesn't seem to be enough info out there on using holes as datum features which is crazy considering how many things bolt together. It's far less common for me to want to use 3 surfaces as my datums. Anyway, keep up the good work!
Mike Walling
Please continue giving more video. I like having the video's available for refreshing my ME major knowledge.
Great introduction to GD&T. Please keep them coming. Thank you.
321 is amazing I am still in shock its a revelation I can understand now the order of datum and why they are so important
Very clear.
Very precise.
Without any unecessary additions.
I will follow this channel closely
Thank you! Welcome to the channel.
I love your videos! Your delivery of the material is crystal clear which makes it relatively easy to understand the concepts. Please, please, please post more GD&T and engineering drawing videos. I'm struggling at work understanding engineering drawings and GD&T. Thanks!
Hi Sherri, I'm glad that my videos are helpful. Its people like you why I started this channel.
I am planning to put up more videos, but the best way to make sure that you're not missing anything is to visit my new website www.theengineersreference.com/
You can get all of my updates and I will also start making my slides available to my subs.
You are more complete than my professors were 30 years ago. They spent an entire 30 minutes on the subject. I learned most of it on the job. I had to teach this to my daughters because her profs didn't mention it.
Thanks a lot! I really enjoy knowing that people are getting something out of my videos.
Thank you for making this easier to understand..! Sure beats reading the flip book..!
Very good explanation. If I can understand then anyone can understand which means the content is great. Thank you
Good Job with the 12-modes of motion or the 6-degrees of freedom...DATUMS are the key to any tooling set-up.
Thanks!
Thomas J. Vanderloop, Author, Technology Instructor & Manufacturing Contractor, CMfgE & LSME
Cmm programmer here , wish i had seen this video when i first started. Well done!
Thanks! That's quite the compliment!
this is the best ever video on gd and t ..i have ever seen on you tube.........thank you 10000 times for that
the 321 rules is a new concept to me its like if the clouds have moved and the light shined on my face.
i mocked up my resume to get an inspecting job..and it worked...now I'm going into this job not really knowing anything until i watched this..definately needed the 3,2,1, rule
LMAO! Good luck!
Hi, thanks for this video that you have put together. I have a few questions for you regarding it if you don't mind - I know little about machining and my questions might be a bit basic: 1. Why would the basic dimension of 16 not be measured from B, as B would be a sure reference to measure from? Why would basic dimension of 34 not be measured from C, as C would be a sure reference to measure from? 2. What importance in terms of tolerance would 10 play, it doesn't seem to have any mention? The surface that it is measured from might be rough and inaccurate when compared to the other official Datum sides (AB & C). Is it not important as to the position of the hole set (the two holes) in relation to the boundaries of the rectangular block it goes through - maybe that block doesn't need to mate up with an adjacent component accurately, but just for it to be attached using bolts? 3. The slide with the 3-2-1 Rule at time 10:02 for example, shows the Right Hand Rule and the 6-axes of freedom. The axes don't coincide in those diagrams (although I can mentally rotate them and see what's going on)...generally speaking, the z-axis is the vertical axis (elevation view) isn't it - thought I would mention this as I think most machine set ups would be with the z-axis vertical (is this the case in industry standards)? Additionally, I know this might not matter, but do you have a preference to which axis has the 3, which has the 2 and which has the 1 restrictions for movement? 4. Why is the term 'counterpart' used, what does this mean in this context - I would imagine it means equivalent part? 5. At time 14:51 it shows the ABC Datums in the control frame and you mentioned that A-Primary, B-Secondary and C-Tertiary need to go in that order and that set up, so even though, some other arrangement of the stops to hold the part in place on the machine would ensure it does not move and all freedoms of movement have been stopped, why would this order be important? Is it related to axis preference or some other preference? AB&C would all be trued up and equally suitable for datums (or are they not?) - is it to do with their specific machining tolerances? 6. The (2x) indicates the two holes I would expect. 7. To achieve a diameter accuracy of 0.001 for example instead of the 0.06 for the holes, would this mean using a more accurate drill bit/chuck/more expensive machine in practical terms - which would make the manufacturing of the part a lot more expensive? Thanks for your help. Kind regards. David.
This guy teaches better than my professor at the college. Love the video.
Big thanks. You have good teaching attributes. Liked. Subbed. Commented. Looking forward to see all your other videos.
I really appreciate your effort and resources you provide thank you for making this video
Thanks for taking the time to watch and comment.
Very Informative -Thank you so much for this information please share additional videos on CMM Basics and measurements
Thanks for watching.
Even though the 3-2-1 rule is common for establishing a coordinate system, it does not satisfy ASME 14.5 for a DRF. In your example, you would need to use 3 perpendicular planes. Datum A feature would locate on the 3 highest points, Datum B feature would locate against the 2 highest points and Datum C feature would locate against the single highest point on that surface.
Very Helpful!!! I have my final tomorrow! Thank you so so SO much!!!!
Thanks for watching!
Just what I needed! Highly informative video. Thank you so much.
Thanks! Its awesome to know that this was helpful to someone.
Ty Mr.Cummins 😎
You're welcome and thanks for watching!
Really enjoyed this I am a Printed Circuit Board Designer in which we do a lot of GD&T,
i love this, helps me to undersatnd gd&t better. thank you!!!
Excellent Explaination
one of the best video i have seen on GD&T
Thanks! I appreciate it!
A couple more points: 1) when Inspecting the part, you must hold the part against the B and C points. It's like putting the part in a vise using only the fixed jaw and a stop, without clamping it between the two jaws. 2) ANSI and ISO standards suggest that the arrows from the feature control frame point to the center of the hole, and not to some place off the outline of the hole. GD&T is about details. The (2x) below the frame makes me wonder why another box was not included in front of the feature control frame to indicate the number of times. Or maybe a break in the leader line would work. That 2X is important. I usually put mine above the left hand box (and ANSI wants 2X not 2x. This is from the drawing board era, where no lower case were allowed like they are now.) and since the information is essential, not a parenthetical suggestion, no parentheses are needed or wanted.
Thanks for watching and your feedback!
Great training, could you upload GD&T tolerances for assemblies interaction.
this person got so clear voice
Thanks!
Thank you so much, very helpful 😊
Thanks for watching!
Nice explained
I paused the video in between to give thumbs up. Please keep making such videos.
Thanks for watching! I really appreciate it!
Great video! Thank you very much, greetings from Mexico
Wow! Thanks! And thanks for watching!
Totally broken down! Thanks!!
Good explanation. The only comment I have is your orthographic projection is 1st angle projection. North America 3rd angle projection is most commonly used.
do you plan to update your video according to ASME 2018?
Very informative and well done! I'm looking forward to your other videos for more information
Great Video thanks
I'm a WELDER by trade but have worked with CNC In the past milling parts I like the video would like to see everything related to topic thanks
Thanks! Its great that you got some value in the video.
I just didnt undersstand. With respect to datum A, how would I inspect the tolerance? actually that's something I want to know. How would I inspect that part if I had to measure it?
When you give 3 datums... it shows the inspector how to place the part while measuring THAT dimension. Rest on A align to B , anti rotate w.r.t C
Excellent video. Thanks for your help.
Great training video.......
Very helpful very detailed ✌️👌👌👌
Thanks 🙂
Very informative and helpful! Subbed. Looking forward for more videos like this from you.
Thanks a lot!
So happy rn... this really helps me in school while in the middle of this covid bs
Very clear cut, no nonense
Next time will watch part 2, I am hooked. 👍
Thanks for watching!
Kindly prepare video lecture on complete Gd&t and tolerance stack up analysis. Its my humble request to you
kudos to you Professor, and much thanx for this easy-to-understand tutorial of gd&t basics!
Thanks a lot! And especially thanks for taking the time to watch and comment!
Very well explained. Thank you for the upload Sir.
English isn't my native tongue and I understood this better than my mechanical drawing classes
Thanks! That's awesome!
BEST explaining , and neat vid ... THANK YOU INFINITY MFG
Thanks for watching! I appreciate it!
Wonderful Lectures ! Thanks.
Very good lecture easy to understand . Im from india
Thanks for watching!
First off, I'd like to thank you for making such an informative video!
Could you please elaborate on the 3-2-1 rule a bit? Isn't the block still capable of moving along the "+" directions of all of the 3 axes? I mean, fixture 1 stops the block from moving along the "-" direction of the Y axis, but it can still slide in the "+" direction, right?
I am confused about this also.
i believe you have to imagine the constraints being mirrored so the movement is limited on both sides!
@Infinty MFG First of all great video! Thanks a lot for your effort in making this video. I have only one question, why does it matter in what order I write down the datums. For example how to change the GD&T if I were to write down BAC and not ABC?
Why am I choosing today to learn when I have a splitting headache?
Thank you.
[Nephew of Ida] I guess this was the most important video of my live. Looking now for part 2. I am more 3D modeler and nobody complained about my drawings. Randomly luck. Because the professor on the training confused me with his explanation of the 3-2-1 rule. Thanks for the video.
Simple yet effective explanation
Thank uou
Thanks for watching!
Brilliant Dr. Cummings! Subbed and learning more!
Thanks for watching!
Good basic knowledge but can you please provide some knowledge regarding datums in relation to net pads resting, 4 way and 2 way for stamping perspectives
Excellent video.
very useful information.... thanks you sir .
we need more videos on gd&t ...
Thanks a lot! Thanks for watching!
Thank you very much for the videos! Can you please explain how the drawing defines the diameter of the circle?
Thank you . Extremely helpful.
Well done professor!
Thankyou very much Sir!
Thank you
such a awesome explanation .. really I learned something what I need. But i have a doubt like . How profile tolerance get effect by MMC ?? I have seen in some blue prints asking profile with MMC !! seeking for your answer.
Hi Raghu, Thanks for watching and commenting.
There are two modifiers that use the same symbol, 'Maximum Material Condition' and 'Maximum Material Boundary'; they use the symbol of an upper case 'M' in a circle. A profile tolerance is subject to MMB, this means that a surface is being treated as a boundary or datum feature (secondary or tertiary). This gives information to the engineer on how to design the gauge (datum simulator) so that the maximum material is accounted for.
You can get more information on this from "Ultimate GD&T Pocket Guide" - 2nd edition on page 38.
Hi sir,
So how bonus tolerance will add to the profile tolerance when some features called for profile with MMC.
Very informative video..!!! Thanks for posting it
Thanks for watching!
Hi Professor Cummings at minute seven you talk about the 321 rule and you have 3A, 3B, 3C. you seem to refer to them as three datum planes…when actually they are the same datum planes… so why would you call them ABC when they’re all co planer?
Thanks for the video. Could you explain those datums and how to select those datums ?
Great videos man, great explanations.....my GD&T instructor is too wordy and doesn’t simplify. Thank you, thank you!!!
thank you great video
Thank you for sharing this!
How come the dimensions do not start from datum planes? They're all from the opposite plane. Don't all dimensions have to originate from or be traceable to datums?
WHY are None of the dimensions given in relation to Any Datem??
The "A" has no relevance to the hole position, the "10" is on the far side from the "C" and the "16" is on the far side from the "B".
Makes no sense to me.
I agree completely with Edd
First thing, that most of the information for that part is left off. I assume that was done to leave only the symbols that the Prof. wanted to focus on.
My understanding of how "A" applies to the hole position, is that because the hole is actually 3 dimensional (a cylinder), the axis of the cylinder is to be perpendicular to plane "A". It made no sense to me until I got away from the idea that the view was a 2 dimensional drawing.
Edd is spot on. Terrible example "Professor" shame on you for adding to the confusion of GD&T. The primary "A" datum controls perpendicularity of the holes (cylinders), the "10" and "16" should be located from the datums B & C (or the datums need to be on the opposite sides where the dimensions are located from). it's fine that the "10" is not "Basic" and therefore it would be the drawing block tolerance which would apply not the positional tolerance, but for this basic lesson it probably should have all been basic dimensions located from their respective GD&T datums. It then would have been a worthwhile lesson . In the real world as presented it would force a call to the engineer and drawing change.
A,B,C in respect to What??
Nice explanation sir.
Why we have to include the datum planes in control frame. What is main purpose of it and how to read them
The control frame and the order of the datums show you the priority of the different datums as well as how the features relate to each each datum. This will inform the operator/inspector how to restrain the part.
Datum Scheme is simple. Typically A|B|C = X|Y|Z X= FORE/AFT Y= CROSSCAR AND Z = ZED(UP/DOWN). Understand this first along with this video and you will get very basic knowledge. The fun stuff comes with datum targets, local alignments, and theoretical datum assignment for parts that are NOT round, flat, or square for example: an airplane blade or a shaving razor. Its called Curve.
Video AT 4.43 SEC, why basic dimension is not given from the datum. I believe the basic dimension to the hole should be given from the datum
Hi Subdash,
You're very observant, the drawing is not perfect, but my hope that there is enough information to help people to understand how the datums are applied to the control frame.
Thank you for the reply.
They don't have to be dimensioned from Datum Feature. If the other side had basic from Datum Feature you could just subtract it.
GD&T cleans up linear dimensions. Thats the idea.
I have such doubts too. For example in the control frame, when tolerance is mentioned and later 3 datums are shown, doesn't it mean the tolerance is for the dimension w.r.t. the three datums? Sorry if I sound foolish. I''m learning
👍
One other thing that minute 951 you said that putting the part on the three points eliminates the ability to go up and down it actually only illuminates the possibility of going down you can still go up, so could you explain that please
Thank you so much sir, you are a life saver.
Thanks for watching!
Sir ,the datums A , B, C are planar surfaces of the equipment.which has to be used for simulation.The points 3, 2,1 are the minimum ponits of contacts which the part shall have when it sets up on the inspection ot manufacturing equipment .This is what you are saying or I am wrong?thanks.
Thanks, you do a great job of teaching
Thanks! I'm glad it was helpful.
Great video learnt lots.
Great info. Thank you
Very clear and informative. Would you suggest any textbook(s) for GD&T (whether one of the 3 in amazon's top 30 in Drafting and Mechanical Drawing or some other)?
Yes, a good book is called, "GD&T Application and Interpretation" by Bruce A. Wilcox
is it always necessary to set the part for machining w.r.t datums because sometimes for example in case of a bearing journal and shoulder we machine them together while holding some other features but in drawings we still give perpendicularity for shoulder wrt the journal, probably a similar video for parts like a casing with bearing could solve my doubt.
Amazing why cant you be my professor mines suck do you teach at any cuny schools in ny like the way you teach is so intresting catches my attention and goes straight to the point
Hello Adel the turtle! Thanks for the compliment! I currently teach in Cincinnati, Ohio. Its good to know that you got something out of this video!
Infinity MFG thank you so much we need more professors like you can you do more videos on this topic showing more tolerance and dimensioning and charts and explain tbe signs like for ex the m or L and stuff like that and practice problems would be nice
Hello sir,
very good & important information
very helpful video, but i wanna know the practical use of gd&t.
plz share a kind of video in which i can learn gd&t practically through engineering drawings.
That's a good idea. I wanted to lay a foundation of the basic rules and then add to the series by apply it to a practical example. thanks for watching and the feedback!
Good job thanks.
Very Good
Great video. This was very clear and informative