How to Apply GD&T Position Tolerance to a Hole

[@axle102]

I love this teaching approach. So practical! I wish many of my courses in college were taught in this way.

[@hondroin]

Straight to the point, and straight into my head. RESPECT thank you for the simple explanation. For once managed to understand what annotations mean

[@SquishMe]

i could watch this guy explain GD&T examples for hours and hours

[@StraightToThePointEngineering]

Much appreciated Mario! I will continue to create more videos and work with everyone to understand GD&T. It ain't easy but with the right practical application approach I think it can be mastered! Thank you for watching and for the very kind, positive, and motivational words here in the comments! Have a fun rest of your evening!

[@MrMoeAl]

I absolutely agree! usually I skip but he is just so good ... he takes step by step and gets straight to the point!

[@crosshairjunkie6903]

@@StraightToThePointEngineering I hope you would come back to your channel and make more videos. They’re the most simple and straight forward ones I’ve seen yet!

[@inochi3000]

Best channel about GD&T on the internet so far. Please upload more. Thank you!

[@kanyinsola.a]

Thank you so much! This was so clear and understandable. Please don't stop posting videos. Thank you!

[@tjvanderloop1686]

The KZbin-video is great. GD&T is used as a Characteristic Control for Position for Assemblies. The instructor worked with basic dimensions an did a fine job explaining how holes are located with "GD&T" ASME Y14.5 Standards. T J (Tom) Vanderloop, Author, Mechanical Designer, & Consultant to Industry; ATEA, AWS, & SME-Leader/Membership

[@taylorjohnson8232]

this was the best GDT video I've ever seen

[@KKLL28456]

Thank you for the help! You 100% live up to the name straight to the point. Extremely concise, clear, easy to understand, and provide applications. Amazing 👏👏👏. I rarely comment, like and subscribe but I can’t help myself for this channel.

[@danielm.9431]

oh my god! Really helpful , thanks for sharing your knowledge :) , Greetings from Mexico

[@StraightToThePointEngineering]

dany m thanks for the support!

[@amolaegade5368]

Dear sir kindly explain on what basis did you chose 0.014 as the tolerance value...is it a general practice in engineering?...I don't understand that please reply

[@jalalsher]

You're the best! Your videos helped me to learn things that i could find anywhere else. Thank you!

[@carlosr6547]

Excellent bro, keep doing videos I will share them with my friends at college

[@StraightToThePointEngineering]

Thanks Carlos Reyes! I appreciate the feedback and the time you took to watch and comment, also, thanks for passing the videos along to your buddies! Hope these videos help and if you have any GD&T topic request just hit the reply button and let me know.

[@jessepartida9119]

Dude, you made this so simple to understand. Thank you and please be encouraged to do more. As Parvin Pandey posted especially on MMC and LMC. Again thank you.

[@StraightToThePointEngineering]

Hi Jesse, I really appreciate the positive feedback! Also, know that I just posted a video on how MMC is used with Clearance Holes. Also, know that I will be posting more GD&T videos on a regular basis due to the amount of positive feedback from the GD&T KZbin community from members such as yourself. Thanks again and have a fun rest of your Sunday!

[@edgarcarrillovazquez8576]

More videos man. Pleaseeee... You are the best

[@pravinpandey375]

Please make video on MMC and LMC relation with manufacturing.

[@StraightToThePointEngineering]

Hello Pravin, I am shooting a video about MMC here within a day or two and I will upload it!

[@Adam-pq2sp]

Thanks for the videos. Looking forward to more.

[@StraightToThePointEngineering]

Hey Adam, thanks for the positive comment! I have uploaded another video on how MMC works with Clearance Holes so check it out when you get a chance. Thanks again and have a great rest of your Sunday!

[@camjc1521]

Great video man, I’m an inspector from United Kingdom and this is such great work

[@vasimmansuri1939]

hello sir,from where we have got .014 value.did u follow any charts?

[@jonathancrist1456]

#3 on board says it is typical.

[@jasmine8847]

Exactly what I was needing help over in my IE 3351 Manufacturing class at Texas Tech University!

[@rahmenbelleili4119]

It is a wealth of knowledge thank you for sharing and teaching.

[@alexpitt9636]

Great video thank you! Sorry if this is a dumb question: Does adding the box around the dimension link it to the geometrical tolerance call-out on the hole? In other words, is the box around the dimension "GD&T" code for "You need to look elsewhere in this drawing for the tolerance on this dimension."?

[@randatatang9222]

I think it just means it's basic dimensions since you don't intend to add any +- tolerances. So you're sort of correct coz seeing a box tells me it's a gd&t tolerance and we definitely have to look for a tolerance control frame.

[@hemanshpandya542]

Hii nice and really helpful video. Can you please tell what does "M" signifies in the symbol ?

[@mauriciocastro6363]

Thank you for the explanation, coud we use this same approach to position a 4 hole pattern in the same plate? What is better, do this single line position tolerance, or a composite tolerance?

[@andrewayer6932]

Great benefit for GD&T understanding

[@shrirambangalore6504]

Sir, How did you got the value 0.14?

[@liorlotr]

You need to divide the 0.014 tolerance by 3 because you have 3 datums?

[@ranjodhsingh8638]

I have a question please help. Can we give position tolerance for a hole on a PCD. If the job is round. Like circular flange. Can we take central axis as a datum to position the hole if not what is the correct way to place tolerance for the holes on pcd

[@kunalgavane4740]

Wow, Great videos. Quality over quantity. Thanks a lot. :)

[@kaiserrazzaq6865]

Hello, what is the purpose of the box dimension? basic dimension? If it's toleranced anyway by a feature control frame?

[@shlomobachar4123]

How do you give position tolerance to holes that are normal to and on a curved surface? For example set of holes that are on a cylindrical large tube (harder case would be holes on a double curvature surface)?

[@ram3208]

Sir, keep posting videos. Thanks for the video

[@pw604]

Very good explanation!!!

[@arronnunez7230]

Good day, Thank you for this video, teaching us GD&T, I would like to ask on how you come up with how much tolerance you put for the position? it is one thing I find hard on choosing the right tolerance for my drawing. thank you

[@jeslint8807]

Excellent. Thanks a lot. Have a great day.

[@saravananrameshjegan9606]

Buddy , your explanations are simple and clear....post more and more gd&t videos...if possible Strength of materials too.....

[@StraightToThePointEngineering]

Hey there Saravanan, I am very grateful for your positive and motivational comment! I have posted another video and will continue to post on a much more regular basis because of positive feedback from viewers like you! I am also seriously considering creating a Straight To The Point STEM channel where I present STEM topics like Strengths of Materials, Fluids, Statics, Dynamics, etc. Thanks again for watching and for commenting! I will look for you in the comments section of my future videos. Hit me up on Instagram @straighttothepointgdt as well if you want. Have a fun rest of your Sunday!

[@bornaleepaul1985]

Which gd&t should be applied if the hole is tapered position or profile? And how it will be inspected?

[@trexinvert]

BTW. This geometric characteristic "assumes" perfect form. The form/depth variation of the hole is covered in the topic "composite tolerancing". Where the top frame = location on the surface, and bottom frame = depth/form control. Do you have any plans to make a video on this? I'm sure a lot of engrs/students would be interested. Thx. Keep on.

[@StraightToThePointEngineering]

Hello there trexinvert! First off, thanks for watching for providing a great suggestion for a future video! GD&T does require perfect form when a feature is at its MMC size. As a feature's size departs away from its MMC size, the feature's form is allow to deviate equal to that amount of the departure. You have an interesting perspective on Composite Positional tolerancing. I'll be honest, I look at Composite Positional tolerance a bit differently. I look at it as a unique tool when dealing with a pattern of features located on a relatively large part or when the location of the overall feature pattern is not as important as the location of the individual features relative to each other within the pattern. For the first case, Composite Positional tolerance allows me to "loosely" locate the overall pattern relative to the overall part but then tightly located the features within the pattern relative to each other. I find this very useful when dealing with relatively large part where it would be difficult to control the tolerances involved with traveling a great distance from the edge of the part to the location of my feature pattern. However, once I get to that location, the distances between the features are relatively small and so it is much easier to control the location tolerances of the individual features within the pattern. For the second case, Composite Positional tolerance once again allows me to "loosely" locate the overall pattern relative to the overall part but then tightly located the features within the pattern relative to each other. Sometimes, on a smaller part, I need to VERY tightly control the relative location of each individual feature within a pattern relative to each other. However, the part function does not require that I apply the same VERY tight control to the location of the overall pattern relative to the overall part. Composite Positional tolerance allows me to break these requirements up and apply different tolerances to each. Let me know what your thought are. I am not sure I completely agree with your simplified assessment of the top portion of the frame only controlling location and the bottom portion only controlling depth and form. My understanding is that the top portion "loosely" controls the orientation and location of the overall pattern relative to the overall part. The bottom portion controls the feature-to-feature orientation and location of each individual feature relative to each other within the pattern. Once again, let me know if you disagree or if possibly we are saying the same thing but using different wording. Thank again for watching and for providing for a more in-depth conversation here in the comments section! Stay safe and healthy and have a great day!

[@benenglish4740]

Super helpful. Thanks for the concise video. Subscribed

[@praveens1516]

What happens if the pecking order of datums r changed?? And can we take the upper surface for datum A or opposite surfaces for other datums?? Is position tolerance applied only to holes and keyways??

[@randatatang9222]

Thanks but where did the fourteen thousandths come from. I would like to know how to come up with that

[@daltonmoree]

I love this video. Very informative and straight to the point as the title suggests. I have one question though; How are you indicating that the hole is drilled perpendicular to datum A? Do we not need to add a box indicating perpendicularity w/ respect to datum A? or does the fact that these datum are supposed to be perpendicular to each other suffice? The way I understand this, the drawing indicates that the cylindrical tolerance zone indicates the hole must lie within .014 of nominal Ø, but orientation of it's axis is not specified.

[@StraightToThePointEngineering]

Hi Dalton Moree! Thanks for watching! When applying various tolerances in GD&T, you tend to get some controls "for free" so to speak. If I control the cylindricity of a shaft, I get circularity and straightness for free. If I control the parallelism of a surface, I get flatness for free. The same thing applies when controlling the location of a hole whose axis is 90 degrees to the Primary Datum with a Position Tolerance. You get perpendicularity for free by virtue of calling out that primary datum. You are essentially controlling the orientation of the hole's axis relative to the Primary Datum by calling out that Primary Datum in the Feature Control Frame. FYI, if the hole is perpendicular (90 degrees) to the Primary Datum, then you do NOT need to state that on the drawing. It is assumed. However, if the hole is orientated at any other angle, then you need to state that angle and now the Position Tolerance controls the orientation of the hole at that stated angle rather than perpendicularly. I hope this helps! Feel free to comment with any additional clarifying questions. Thanks again for watching and stay safe and healthy!

[@oldschool1436]

@@StraightToThePointEngineering One thing I never understood (till now) was the purpose of datum A whenever I see a drawing like you have. An answer as simple as this made it all make sense. Datum A is there to lock in the hole's orientation.

[@robertrumfelt7843]

Nice and "straight to the point". However, you used 3.00 to illustrate the "boxed" dimension, then inserted 1.50 for the dimensions for locating the holes. I don't get it. Why did you "box" the 3.00 and what does it have to do, if anything, with the 1.50 dimensions?

[@TheSandeepypatil]

A NICE PRESENTATION AND EXPLANATION

[@meetshreepal3903]

well you did not explained why you pick 0.014 ? why not 0.016?

[@warandv6614]

Brilliant explanation

[@stevenbrown6717]

Awesome! Thanks for the tips, Caleb

[@StraightToThePointEngineering]

Steven Brown Hey Steven! Thanks for checking out the video! I'll be adding more on GD&T and other topics all the time going forward.

[@EnvoyofCthulhu]

Man I wish you taught my college classes, your tutorials are so easy to understand. Thank you!

[@ushapotbhare5599]

Hey video is good and I also one question because I give interview in Mercedes Benz r&d and they given me same part you shownbinvthis video but they also correct me on the hole also get seperate gd and t for not get inclined.

[@ben10_prvn]

how did you get the 0.014 tolerance, can u plz explain to me? and explain modifier too.

[@StraightToThePointEngineering]

Hello there Benny! I actually have two videos that talk about both of your questions. The first video which explains why .014 is a great starting point when selecting a practical position tolerance can be found at: kzbin.info/www/bejne/oaHCaXx9qp2Fm9k The second video which explains how and why MMC is used when controlling clearance holes can be found at: kzbin.info/www/bejne/i4m9m4eYaL-Ih6s Thanks for watching and for the great questions. Let me know if these videos did a descent job at answering your questions. Please stay safe and healthy and enjoy your day!

[@bharatbauskar369]

Thank you very much sir for your efforts. Sir, can you make a video on "How much mm gd and t is given to a specific part?

[@Dubconnectgang]

That really helped me a lot!

[@magoadicto1]

i work in a metrology lab and i use a faro arm and a cmm machine , my trouble is when i need to use the GD&T evaluation , sometimes when i put , true position against abc, the nominal measurement sometimes is 2,000mm for example, but if i evalu bca the nominal position its okay, Why is this happening ?, thanks for your time

[@StraightToThePointEngineering]

I am having a bit of trouble understanding your question however from your description I have one possible suggestion. The order in which the datums are listed and which surfaces they are associated with are very important. During inspection the first listed datum will require three points of contact with the inspection equipment surfaces. The second datum listed will require two points of contact with the inspection equipment surfaces. The third datum listed will only require one point of contact. If you are evaluating the position of a feature, you need to be sure you are correlating the correct datums to the correct surfaces and also that you are establishing the correct order of the datums both within your physical inspection setup as well as within your inspection software. Feel free to comment back if you wish to discuss this further and attempt to work out a clarification.

[@ganeshnikamgn3263]

thanks Jonny bhai💥

[@Simon_B]

What is the importance of boxing the dimensions 1.500?

[@StraightToThePointEngineering]

Hello Simon, the importance of boxing the 1.500 dimension is to let the quality inspector know that the dimension is what we call a "basic" dimension. In this case the quality inspector uses that basic dimensions to locate the .014 tolerance zone precisely 1.500 away from the datum. Then he/she will probe the hole, find the actual axis of the hole, and then make sure that axis falls within the .014 diameter cylindrical tolerance zone. I'm sure you're used to seeing the location tolerance given to the machinist as part of the location dimension itself. GD&T removes the location tolerance from location dimension and instead gives the machinist tolerance through the use of the positional tolerance callout (the .014 value). Think of it like this, we use a perfect "basic" dimension to locate the .014 tolerance zone, then the axis of the hole feature has to fall inside that .014 tolerance zone. So your location tolerance is no longer a rectangular shape dictated by your +/- location dimensions but rather its a "basically" located cylinder with a diameter of .014.

[@Simon_B]

Great thank. How would the inspector report out the measurements? For example if A was 0.004, B was 1.514, C was 1.510? They are all in tolerance but would the inspector just report out the maximum so 0.014?

[@StraightToThePointEngineering]

Hi Simon, you can quickly determine how far off in the X and Y (B and C respectively) the hole is by using the formula (X-Drift^2 + Y-Drift^2)^0.5. You could also restate the formula like this: (B-Drift^2 + C-Drift^2)^0.5. The X-Drift is the absolute value of |1.514 - 1.500| = .014. The Y-Drift is the absolute value of |1.510 - 1.500| = .010. Then you plug in those values to the equation (.014^2 + .010^)^0.5 = .0172. So .0172 is your total hole shift. If I was generating the inspection report I would report those three values (X-Drift = +.014, Y-Drift = .010, Total Hole Drift = .0172). To continue further, since .0172 is greater than .014 then initially I would suspect this part to be bad. However, since Maximum Material Condition (MMC) was listed in the Position Tolerance I would then need to know what the actual measured hole diameter is. Once you know what the actual measured hole diameter is you can determine whether or not .0172 violates the allowable Position Tolerance. I actually just posted a video on how MMC affects Positional Tolerance so check that out to better understand why you would need to know the actual measured hole diameter. Now for the "0.004" value you listed relative to Datum A. You would need to know what that value means. Is it an declination angular value or a is it some sort of location measurement? If it's an angle measurement, then would .004 be too large of an declination relative to Datum A. Its hard to say without the inspection software providing some insight. But to be clear, you need more information to know how to list the ".004" value in an inspection report. And you need more information overall (hole diameter, .004 declination interpretation relative to Datum A) to make the decision on whether the part should be accepted or rejected. Thanks and feel free to respond to this with questions for clarification or if you have more insight. Have a great rest of your Sunday!

[@ash_deol]

Very nice Sir👍

[@vijaymerni]

Why the Datum A using this condition for position tolerance.As per the reference we have already 2 datums fixed as B and C ?How this condition we can use Datum A? if we are using perpendicularity we can use datum A rit! Please explain..

[@StraightToThePointEngineering]

Hi there Vijay, we first want the tolerance zone to be perpendicular to the Primary assembly surface because it is a clearance hole for a fastener. So we list Datum A first to Orient the tolerance zone perpendicular to Datum A. Then we list the following two Datums B and C to Locate the tolerance zone from the Secondary and Tertiary assembly surfaces. So to be clear, we list Datum A to orient the tolerance zone and then we list Datums A and B to locate the tolerance zone. Feel free to respond with additional questions or comments and thanks for watching!

[@vijaymerni]

@Straight To The Point : Thank you very much. So we can use the all datum for position tolerance rit at any situation? If u don’t mind please send me u r mail I’d for if have any further doubt I will contact you..thank for the reply sir..

[@StraightToThePointEngineering]

Hi again Vijay. I hesitate to say that something can be absolutely used in "any" situation. I would say that what I have posted in this video is a very common design scenario that can help guide you in your situation. My email is [e-mail] If you have a specific design application question you can contact me through that email. Thank you again for watching and engaging in the comments section.

[@vijaymerni]

@Straight To The Point : Thank you very much sir.. I am sorry if I am wrong.. sure definitely please support me. Please put video other symbols tolerance usages also.thanks for the reply.

[@nickritter1992]

good video straight and to the point

[@StraightToThePointEngineering]

Thanks for positive comment Nick! Have a great week!

[@CesarLopez-qt9mo]

-Very good explanation. Follow uploading videos, thanks a lot.

[@StraightToThePointEngineering]

Hey there Cesar! Thank you for the positive feedback! I will continue to create new videos and together we'll kick GD&T in the rear! Thanks again and have a great rest of your evening!

[@shiwangijaiswal1606]

Hi, I really like your tutorials. Request you to please also explain RFS.

[@rishivanth5012]

Sir what is feature condition modifier and datum condition modifier

[@StraightToThePointEngineering]

Hi Rishi Vanth! First, let me be very clear that placing the MMC modifier next to the tolerance zone size is very different from placing it next to a datum listed in the Feature Control Frame. Placing it next to the tolerance zone size tells the machinist and inspectors that as the hole size increases (moves away from the MMC size of the hole) you are allowed to add that amount of hole size increase to the tolerance zone size. So in this example the hole size at MMC is .529. Say the hole was drilled by the machinist and then it was inspected and the actual size turned out to be .536. This is an increase of .007 inches. If MMC was used then you can take that .007 and add it to your positional tolerance size. So your positional tolerance allowed would now be .014 + .007 which is .021 inches. This is a concept that should NOT be necessarily used with every hole but it can be used when your hole is a clearance feature for some hardware or part that is being inserted through it. You should always look at the function of your part and your features when deciding if you should use the MMC modifier. As for placing a MMC modifier next to a datum listed in the Feature Control Frame. This is also a concept that should NOT be applied in every situation. Instead, the function of the part and the feature will determine whether or not to use this. Also, you should only place MMC next to a datum that is referencing a datum feature that is a "feature of size". By placing MMC next to a datum feature of size you are telling the inspector that they are allowed to use what is called a "fixed" gauge. A fixed gauge has one size and is not adjustable. When a part is placing in or over a fixed gauge, the part can potentially move around a bit since the fixed gauge will not expand or contract to fit the exact size of the part. This part movement is called "shift" or more specifically, "datum shift". This datum shift during inspection will allow some features or patterns of features that would normally be out of positional tolerance to come back into tolerance as the part is allowed to shift within or on the fixed gauge. This is a concept that is better explained in-person and with visual aides. However, some research can be done. There is an excellent pdf out there by Applied Geometrics Inc that talks about this concept towards the end of the document. Here is the link: members.marticonet.sk/jkuba/normy/ASME_Geometry_Dimension%20and%20Tolerances_Handouts.pdf

[@Hallowed1907]

Sir U r a Sniper

[@StraightToThePointEngineering]

Amit, seeing you again here in the comments section. Much appreciated man! I will continue posting more videos on a much more regular basis so keep on the lookout!

[@shalottradingacademy919]

Sir, make a video on basic GD&T

[@Zakariae92]

Thank you very much, it's very helpful. Even though I don't see why we use datum A. B & C are enough in this case I guess to locate the hole center.

[@StraightToThePointEngineering]

Hello Wasfi Zakaria! First, thank you for watching and for taking the time to comment. Second, I completely understand your dilemma. It didn't make sense at first to me either. However, the first datum A provides two important pieces of information that has nothing to do with locating the holes in an X and Y plane that we typically would think of. The first important piece of information is that it lets the machinist know what surface the hole should be drilled perpendicular to. This helps them create their machining setup. The second piece of information it provides is to the inspector. It helps establish what is called the Datum Reference Frame. Think of it like this, you have this part that was just machined and you send it to the inspector for inspection. The part is technically floating in space and it has 6 degrees of freedom until you provide explicit instructions to the inspector on how to place the part in their inspection setup. Datum A is the “primary” datum and it tells the inspector what part surface should come in contact with the inspection equipment first. This eliminates three degrees of freedom (1 translation degree and 2 rotation degrees). Datum B is the “secondary” datum and it tells the inspector what is the next surface that should come into contact with the inspection equipment. This eliminates two degrees of freedom (1 translation degree and 1 rotation degrees). Datum C is the “tertiary” datum and it tells the inspector what is the last surface that should come into contact with the inspection equipment. This eliminates one final degree of freedom (1 translation degree). So now let’s think about this from a practical application perspective. By listing A, B, and C, the inspector knows to place the part surface designated as datum A down on their inspection equipment first. Then they know to slide the part to the left and make datum B contact their inspection equipment. Then they know to finally slide the part down to make datum C contact their inspection equipment. By doing this the part is becomes completely engaged by the inspection equipment and no longer has any movement that would need to be controlled. This is typically what you shoot for with your datum callouts. You want to call out the functional surfaces of the part that you want the inspector to engage with their inspection equipment which will lock down the part’s movement or degrees of freedom. After they place the part in the inspection setup using the “instructions” you provided by listing the datums, they will then inspect the location of the hole using the datums and location dimensions you specified. I hope this helps. If you are fuzzy on portions of this, feel free to reply. Thank you for watching and have a wonderful week!

[@milindparsoya]

@@StraightToThePointEngineering I searched so much on the internet only to find an explanation here! Finally! Thanks a lot! (Why is the information around GD&T so unorganized and why isn't it taught in mech degrees!!!!)

[@GrumpleslamAlabaster]

Awesome Video!!!

[@mukeshkumarcap4139]

Easy to learn 👏

[@nikhilkulkarni5370]

What happens when our tolerance in only negative side ??

[@StraightToThePointEngineering]

Hey there Nikhil, no worries. When you calculate total hole drift from the B and C axis, the formula will square the negative values which will eliminate the negative sign. A negtive sign simply tells you what direction the hole is out of true position. The formula to calculate the total hole drift is Total Hole Drift = (B-Drift^2 + C-Drift^2)^0.5 so as you can see a negative value is not an issue. However, here's a quick tip, if you are consistently receiving negative values when you are machining holes using a particular setup, then you might want to look at the backlash compensation of the machine you are using. It may need adjustment to start bringing your location values a little closer to the nominal true position. Thanks for watching and thanks for commenting! Have a fun rest of your Sunday!

[@Mech.Masters]

You missed to explain about Modifier 'M'.

[@StraightToThePointEngineering]

Hello there Mech E, I have just uploaded a video that explains how MMC works with Clearance Holes. Check it out and provide feedback in the comments if you get a chance. I would be interested to know you thoughts on it. Thanks again for participating in the comments section and have a great rest of your Sunday!

[@joseoropeza8495]

Good explanation!!

[@StraightToThePointEngineering]

Thanks Jose, much appreciated!

[@robinsingh9191]

What is significance of datum

[@StraightToThePointEngineering]

Hello Robin, a datum is a reference surface or feature. The designer needs to establish a surface or feature to begin locating and orienting other features from that surface. An example would be a hole. It is not enough to specify the size of a hole. The designer must also locate the hole relative to some other reference surfaces. Those reference surfaces would be what we call "datums". A note of caution, as a designer you need to select reference surfaces or "datums" that mimic how the part interacts within the higher level assembly. In other words, do not pick arbitrary surfaces to locate holes from but rather pick surfaces that dictate how that part will fit into the higher level assembly. To reference back to my hole example, always pick datum surfaces to locate the hole in a way that ensures it correctly lines up with the feature that it is supposed to interact with in the higher level assembly.

[@drakecage1544]

Good video but the plane of the first datum A is located parallel to the holes' center axis and not perpendicular as you mentioned. But simple and straight forward explanation btw.

[@StraightToThePointEngineering]

drake cage Hello and Good Morning! Thanks for watching and commenting. I think have to disagree with you on this one though, the hole's center axis is orriented 90 degrees with respect to that bottom surface of the plate which I am calling out as Datum A. That makes it perpendicular to that surface. Feel free to respond with more details if you feel I am still in error. I really enjoy learning and I would be very interested in your perspective! Thanks again!

[@drakecage1544]

Thanks for pointing this out. I got a bit confused after watching once. From a second look, i now agree with the perpendicularity of both features.

[@StraightToThePointEngineering]

drake cage Thanks for the honest reply, that doesn't happen very often on KZbin. You're a stand-up guy! Have a good one!

[@sibimurugesh2565]

Sir but the G.tol is greater than size it's break Rule1 please explain about it

[@StraightToThePointEngineering]

Hello sibi murugesh! Let me explain a bit how this type of tolerancing scheme works. In this situation both tolerances actually work together to completely control every geometric aspect of the hole. To start, the Size and Form of the hole's surface are controlled by the .012 size tolerance in combination with Rule #1. After that, the Location and Orientation of the hole's axis relative to the specified datums are controlled by the .014 Position tolerance. To be clear, the .014 Position tolerance does NOT in any way allow the hole feature to deviate in size or form in a manner that would violate Rule #1. The .014 Position tolerance ONLY specifies the diameter of the cylinder that the axis of the hole must reside in during inspection. Let me put it in a practical scenario. After this part is machined, the quality inspector would first inspect each local size of the hole throughout the thickness of the part to ensure that it falls within the .012 Size tolerance specified. Then they would make sure the Actual Mating Envelope of the hole does not violate the .012 size tolerance specified. Finally, the inspector would locate a theoretical .014 diameter cylinder at True Position relative to the datums specified by the Feature Control Frame and then they would make sure the axis of the hole resides in that .014 diameter cylinder. Hopefully I've made it clear from this explanation that the inspector uses both tolerances together to fully inspect the hole while knowing that each tolerance is independent of the other and each tolerance controls a separate portion of the hole's geometry. To summarize: the inspector first uses the .012 Size tolerance to inspect the Size and Form of the hole's surface and then they use the .014 Position tolerance to inspect the Location and Orientation of the hole's axis. As a final note, I did include the MMC modifer next to the .014 Position tolerance. This means that if the inspected hole size deviates away from its MMC size towards its LMC size, that amount of size deviation can actually be added to the .014 Position Tolerance as a sort of "Bonus" Position tolerance. This addition can only occur up until the point where the hole reaches its LMC size. Any more deviation in size beyond LMC would mean that the hole no longer falls within the specified size range and so the part would fail inspection at that point. Thank you for watching the video and participating in the discussions! Hope this explanation helps and feel free to respond to me with any comments or questions you might have!

[@sibimurugesh2565]

doesnt the geometrical tolerance of position should be within the size tolerance of the feature ?

[@StraightToThePointEngineering]

No, not at all. The Positional Tolerance in this case only defines size of the cylindrical tolerance zone that the axis of the hole must lie within during inspection. It does not have any relationship to the actual form or shape of the hole itself. Positional Tolerance is not a form or size control. It only controls the location of the axis or centerplane of the feature it is applied to. I think you might be thinking of form tolerances such as cylindricity which requires that the tolerance be smaller than the size tolerance specified.

[@seenivasanr5213]

Thank you so much sir

[@josepharulraj2924]

Good video. Kindly increase the audio level.

[@StraightToThePointEngineering]

Hi Joseph, I am working on improving the audio and presentation format. I have incorporated a microphone and will introduce a new presentation media in my next video. Keep watching and thank for the words of encouragement! Have a wonderful rest of your evening!

[@vaibhav033]

Hello, I have position frame from very old drawing, which is quite difficult to understand. Can you share your email so that I can show you the frame.

[@YousingBD]

Very good video for sleep

[@ergun_keskin]

Please go ahead with GD&T

[@StraightToThePointEngineering]

Roger that Ergün! I will proceed! Thanks for watching and commenting. Check out my latest videos if you want some more practical GD&T guidance! Have a good day!

[@SkodaTk88]

Why such precision? No table drill or boring machine will make a proper hole anyway?

[@alexanderjack5937]

To the point!! Like for you

[@StraightToThePointEngineering]

Alexander, thank you Brutha! I will keep posting more on a regular basis now that I am getting positive feedback from "most" of my viewers! Have a great rest of your Sunday!

[@farmerking1135]

great content

[@jaredbee8133]

This is great.

[@rev2889]

why would an engineer use .000" for a tolerance?

[@Donzaloon]

The tolerance would look something like .000, +.010.. so for instance if you wanted a hole at .30 you are telling the machinist that he can't go under .30 at all but he can go over by + .010. So your tolerance would be .000 +.010 instead of your traditional +/-

[@rev2889]

@@Donzaloon they really want zero tolerance. I finished the parts. Did best effort and of course it worked. And got paid. Thanks for the vid.

[@deanwatts5919]

@@rev2889 I am wondering if an M or an L in a circle followed that tolerance of zero? If so, that is the best way to assign tolerances. The tolerance that could have been included before the M (MMC) or L (LMC) modifier is then to be moved up to the size tolerance, to provide a situation for which the most parts can be accepted. If just saying that a larger size tolerance is provided, so the overall objective is to accept the most functional parts possible is not making sense, then please reply. Also, see ASME Y14.5-2009 paragraphs 7.3.4, and 7.3.5.3 on pages 110 and 114.

[@rev2889]

@@deanwatts5919 it was least material condition. Which was plus .0005 minus nothing. I'll send you the drawings if you want to look it over. I finished the job customer was happy.

[@deanwatts5919]

@@rev2889 - So the size tolerance was plus .0005 minus nothing and there was also a position tolerance of zero at LMC? If so, that sounds like a really tight combination of tolerances. If the feature was a hole, so the LMC size limit was the plus .0005 limit, then if the hole's diameter was as far from that limit as possible, so very near the "minus nothing" nominal size value, the additional/bonus tolerance you would have would give you a position tolerance of up to .0005. The entire approach of the language having M or L modifiers after tolerance values is kind of convoluted, since there's a surface method (often called a surface interpretation) that can also be used.

[@theCPadministration]

Thanks

[@StraightToThePointEngineering]

Hey Christian, thanks for watching and for the straight to the point comment :;)

[@ehsanmofrad5389]

thank you

[@ObelixCMM]

Don't mix up Datums and Datum Features, those are Datum Feature symbols not Datum symbols. Datum Features are not assigned by machining procedure but by their use in application of the part. It is Feature Control Frame not GD&T symbol.

[@anthonykennedy7497]

New Mexico State Alumni!!

[@mrdiv8418]

Love it!

[@shokhnurrizakulov5096]

excellent

[@Dubconnectgang]

Thx

[@paymanmohammadrezaei2947]

tanks

[@garchah1]

Legend!

[@prabhudattadash2131]

Please work on your Audio Quality... It's poor

[@componentengineeringqualit4337]

For those of you looking for True Position hole position measurement, check out the TruPosition probe kzbin.info/www/bejne/fqPSoI1nn8ueipI

[@ARentertainment4264]

Nice

[@abhishekr177]

Thanks allot

[@michaely9877]

Tertiary is always based on the primary.... the fuck?

[@montluelweg1753]

Thxxxx

[@marktrotter6930]

"Boxed dimensions" should be "Basic dimensions".

[@beatsbytex]

I can tolerate this

[@joshjosh4716]

Your voice is a little bit low.

[@montluelweg1753]

Cool

[@farhadkarami8927]

👍🙏