at 3:13 you calculated GD&T with bonus as .05. what value is this number? The part is already made? How do you tell if it is scrap or usable based on that number. 05?
Does GD&T possible with feature's tolerance more than true position tolerance? example circle is 1.500" ± .05" and asking true position from A AND B .025" NO MAXIMUM MATERIAL CONDITION. we can check this by using CMM but what if we want to design go/nogo gage (functional gage) does it possible with this tolerance of true position and circle it self?
Thank you for your suggestion. I realize that there were more comments requesting this. I am still thinking about what would be the best think to do. I think (unreasonably probably) that if one reads the text, they have a chance to stop and take some time to think about what is in the picture - analyze it. On the other hand, if I added voice, one could turn it down in order to not be detracted by my voice. Please give me some more time to research this. If I find that adding voice benefits the viewer, I will repost the relevant videos with voice comments.
Hello, let say the hole shift to the left. So the X minimum location is 0.99. When there is Maximum material condition, and the hole is at 1.52, so the X minimum location is 0.97 or still at 0.99. Thank you so much
I draw the circles according with you video, but I got a circle outside the original design...why should I accept the new circle?, can I send you an image?
For hole, you mentioned bilateral tolerance, since the basic size is 1.5 is it really possible during manufacturing of hole to produce hole of 1.48?? Plz reply
It is possible to produce any size hole, which includes nominal, oversized, undersides, and everything in between. However, as you ked me if a specific hole diameter can be made, it is very improbable due to uncontrollable process variables. This would include spindle run out, size of tool variations, and tool wear just to name a few. In conclusion, it is possible to make 1.48 diameter hole, but it would be hard, if not impassible, to make it on purpose. That is why we usually allow for range of sizes called tolerance. I hope this helps.
The actual tolerance could be obtained by many means. There are calculations taking in consideration other components of the assembly, and their tolerance.There could be some historical data to set the tolerance. The experience of the designer is important too. For me, combination of all these work most of the time. Whatever method you use, make sure that the tolerance is realistic and not tighten (made smaller) than it needs to be. The tighter the tolerance, the more difficult the manufacturing is, and hence, more expensive.
I think he means how is the True Position Tol Dia calculated from coordinate ±. Not how the value of the mfg tolerance is determined, established or created per machine/company...etc. I know that is a big deal, but I think most students are just trying to figure out how to calculate from ± to true tol Ø.
I have two answers depending on your background/knowledge: If the tolerance for the hole position is ±.005 in both vertical and horizontal position, then what is true position diameter tolerance? 1.) Rule of thumb: multiply (.005) x 2.828 = .0141. 2.) If you know algebra/geometry, then use pythag theorem to calculate the hypotenuse for a triangle with legs = .010. (it's not a complicated equation, but once you understand the set-up you will never be confused by rules of thumbs)
I sent this video to our engineers as part of a technical training bulletin because they're notorious for putting true position on everything without MMC/LMC on our drawings.
Hi, I have doubt on Positional tolerance when they are applied on length dimension..ex, a shaft with 10mm dia here OD is Datum B and one side face of the shaft is Datum A and other side face asked for 0.1mm position w.r.to A and B...and the length is 50mm basic dimension...Now what is teh tolerance to be applied for 50mm? Thanks in advance...if the question is not asked in clear... please give your mail id...I can mail you
Normally you would not dimension lengths (especially overall lengths) using GD&T. However, if you have to, the phi (diameter symbol) should not be specified in the tolerance box of the GD&T frame. You would use the A and B datums to constrain the part. The nominal plane of the length (50 mm) would be created from the base ( in your case datum A). Then you would offset this plain in either direction, along the axis of the part, 0.05 mm one way and 0.05 mm the other way thus creating a 0.1 mm tolerance zone. In this case, not having any modifiers, it would be like +/- tolerance; however the GD&T tolerance measurement value would be double of what the delta value is. So let's say you measured the actual length to be 50.005 mm - your GD&T measurement value would be 0.01mm. I hope this helps.
Srinivas, I am not sure I understand the question. What do you mean by "that" in your first sentence? None of the information in this presentation effects the datums. There is a way to "float" the datums but this will be separated presentation. The tolerance is effected by applying either MMC or LMC. Please follow up if this does not answer your question.
I guess the question is "why do we need the datums?" The datums constrain the part in space. Imagine that you measure the distance of 1.00, in our example. If we are using, for example, a vision system and select the left edge, move over to the hole center to measure the distance, and the part was not aligned ( it was placed on an agle) with the linear movement of the inspection device, such as the vision system, the measurement would not be correct.
@@PawelGorka1 hi sir could you create a video with datums and little bit of knowledge in gd&t, suggest the good book of gd &t please sir Thanks & regards Pakala Srinivas
First, let's thnik about why we need the GD&T. It is used primarily in manufacturing so later during the assembly process and the use of the parts, they fit and work together reliably. GD&T helps us to make parts with consistent sizes and/or parts that consistently meet other specifications. In case of this video example, the bigger the hole the easier it is to insert the mating part, hence the hole can be off the perfect location more than if it was smaller. In other words, there is more clearance between the holes and the mating pins when the hole is bigger allowing to compensate for any misalignment. Ofcourse, the tolerances are calculated during the design process, and to explain how they are decided would be a different discussion. In order to further explain the changing tolerance concept we will look at an example. Let's imagine two square plates. Plate A has two holes, and plate B has two protruding pins. Now, we assemble these parts so that the plate B pins enter holes on the plate A. If the sizes of the holes are a bit large than the diameters of the pins, it is easier to mate these two parts.They fit together without any interfierance. But, why would we go to all this trouble of allowing for the tolerance to change? We want to make manufacture easy. In manufacturing, easy equals less expensive. In general, when we design parts we want to allow as much tolerance as possible; it facilitates the manufacture. It reduces the manufacturing costs. For example, with large tolerance, the machines used don't have to be very accurate, hence they are less expensive. Or, the process can be faster- time is money. I hope this helps. Let me know if you need more information.
The role of the datum in GD&T is to constrain (suspend) and align the part in the space for the measurements. By definition, the first datum (primary) is a plane, the second one (secondary) is a line, and the third datum (tertiary) is a point. Therefore, in the example provided in this video, the datum A prevents the part from moving up and down in the plane of screen along the datum B. It also prevents the part from rotating in the plane of the screen as well as in the plane of the face along datum B. Next, the datum B prevents part from moving left and right along the datum A in the plane of the screen. However, there is nothing preventing the part from moving in and out of the screen in direction parallel to the datum A. In addition, there is nothing preventing the part from rotating around the datum B (remember this is the secondary datum -a line). I admit that I did not put too much thought into placing these datums for this video. My concern was to explain the tolerance. However, you should use all three datums whenever it is possible. Imagine that this part rotates by an angle around the datum B. If you try to measure the 1.00 basic dimension while still looking at the part in the screen plane that distance will be considerably shorter than it is in reality (you could experience that using a vision system if the part does not sit flat on the table due to some burr or debris on the bottom face, for example). Even though it is very hard to account for every part and every design, once again, one should use all three datums whenever it is possible. However, there are instances where one could not use more than two datums. For example, imagine a tube with a hole drilled perpendicular to the tube’s axis, somewhere along the length of the tube. One end of the tube should be designated as datum A (this needs to be a face), datum B could be designated as the axis of the tube's inside or outside diameter (the secondary datum is a line). However, there is no third datum to be designated - there are no other features that could be used as a datum. I will try to add video on this subject; however, meantime, I hope this helps
I don't add sound to my videos, as I think it might be a destruction. When you read you have to concentrate. But it is not to say that I will change my mind in the future. I am happy you found it useful !
I am sorry, but I am not sure what you mean. If you asking for a true position example for a shaft or a pin, the concept is the same as the one for a hole. You just have to realize that the maximum material condition (MMC) for a shaft means that the shaft is at its largest diameter allowed by the tolerance.
1.48 is the minimum allowed diameter of the hole. Starting at 50th second of the video, there is the diameter identified with +/- tolerance. Also, at 3 minutes and 17 seconds of the video there is a call out identifying this number. Hope it helps.
I did this kind of on purpose. I thought that viewer will have a chance to concentrate more on the content. But I will experiment with sound once I have some time.
The only video that explains GD & T without confusing the hell out of me. Believe me I've looked at all other explanations. Well done & thank you!
I have watched 100 videos on gd&t but understand level is 0% after this I got some idea about position system. Thank you sir
Amazing explanation. Better than the 50-minute long explanation i got in class
Well done! This short video cleared up my confusion.
I am glad I was able to help
This is the best one among the videos available. Thanks a ton.
seems to be a very comprehensive and well edited Video - is it my computer or is the audio missing ?
Well explained never understand the MMC until I've watched this video thank you
Shuold explain the 14 geométric controls. You are great explaining .
🤩Great! Thank for the help!
Great video. Special thanks !!!
If the coordinate tolerance = ±.01, then true position Ø=(.01) x 2.828 = .028. Or, simply .03, I think the round "down" is confusing some watchers.
at 3:13 you calculated GD&T with bonus as .05. what value is this number? The part is already made? How do you tell if it is scrap or usable based on that number. 05?
Does GD&T possible with feature's tolerance more than true position tolerance?
example circle is 1.500" ± .05" and asking true position from A AND B .025"
NO MAXIMUM MATERIAL CONDITION.
we can check this by using CMM but what if we want to design go/nogo gage (functional gage)
does it possible with this tolerance of true position and circle it self?
Very useful.. Looking forward for more videos on gd &t and tol stack..
Thank you. I will try to add more once I am bit less busy.
short video but well explained, thank sr,
sir one suggestion
If you give an audio explanation .The understanding becomes more clear
Thank you for your suggestion. I realize that there were more comments requesting this. I am still thinking about what would be the best think to do. I think (unreasonably probably) that if one reads the text, they have a chance to stop and take some time to think about what is in the picture - analyze it. On the other hand, if I added voice, one could turn it down in order to not be detracted by my voice. Please give me some more time to research this. If I find that adding voice benefits the viewer, I will repost the relevant videos with voice comments.
Sir pls i need other GD&T symbols explaining in this similar fashion. You are best in explaining these without saying anything.
Hello, let say the hole shift to the left. So the X minimum location is 0.99. When there is Maximum material condition, and the hole is at 1.52, so the X minimum location is 0.97 or still at 0.99. Thank you so much
Wonderful video to understand.
Can you make a video with LMC
Thank you
@pawel Gorka ur videos sounds good. did u cover all GD&t parameters?
Very nice explanation Mr.powel
I draw the circles according with you video, but I got a circle outside the original design...why should I accept the new circle?, can I send you an image?
Yes my email is at the bottom of the vide.
thanks for the video, this is a perfect explanation
Many thanks, the best video for the subject
My pleasure. I am glad you found it useful!
the bonus tolerance will be applies to the mating pin right?
In this case, the bonus tolerance applies to the hole. This drawing does not provide any information about any mating components of the plate.
good explanation
Hi. How are you? Please how can I calculate the slot position? Can you make video?...tks
For hole, you mentioned bilateral tolerance, since the basic size is 1.5 is it really possible during manufacturing of hole to produce hole of 1.48??
Plz reply
It is possible to produce any size hole, which includes nominal, oversized, undersides, and everything in between. However, as you ked me if a specific hole diameter can be made, it is very improbable due to uncontrollable process variables. This would include spindle run out, size of tool variations, and tool wear just to name a few. In conclusion, it is possible to make 1.48 diameter hole, but it would be hard, if not impassible, to make it on purpose. That is why we usually allow for range of sizes called tolerance. I hope this helps.
it's called hole interpolation.
The TOP!
How do the GD&T tolerance zone of dia .02 calculated?
The actual tolerance could be obtained by many means. There are calculations taking in consideration other components of the assembly, and their tolerance.There could be some historical data to set the tolerance. The experience of the designer is important too. For me, combination of all these work most of the time. Whatever method you use, make sure that the tolerance is realistic and not tighten (made smaller) than it needs to be. The tighter the tolerance, the more difficult the manufacturing is, and hence, more expensive.
I think he means how is the True Position Tol Dia calculated from coordinate ±. Not how the value of the mfg tolerance is determined, established or created per machine/company...etc. I know that is a big deal, but I think most students are just trying to figure out how to calculate from ± to true tol Ø.
I have two answers depending on your background/knowledge:
If the tolerance for the hole position is ±.005 in both vertical and horizontal position, then what is true position diameter tolerance?
1.) Rule of thumb: multiply (.005) x 2.828 = .0141.
2.) If you know algebra/geometry, then use pythag theorem to calculate the hypotenuse for a triangle with legs = .010.
(it's not a complicated equation, but once you understand the set-up you will never be confused by rules of thumbs)
How tolerance zone became 0.06
I sent this video to our engineers as part of a technical training bulletin because they're notorious for putting true position on everything without MMC/LMC on our drawings.
Hi, I have doubt on Positional tolerance when they are applied on length dimension..ex, a shaft with 10mm dia here OD is Datum B and one side face of the shaft is Datum A and other side face asked for 0.1mm position w.r.to A and B...and the length is 50mm basic dimension...Now what is teh tolerance to be applied for 50mm?
Thanks in advance...if the question is not asked in clear... please give your mail id...I can mail you
Normally you would not dimension lengths (especially overall lengths) using GD&T. However, if you have to, the phi (diameter symbol) should not be specified in the tolerance box of the GD&T frame. You would use the A and B datums to constrain the part. The nominal plane of the length (50 mm) would be created from the base ( in your case datum A). Then you would offset this plain in either direction, along the axis of the part, 0.05 mm one way and 0.05 mm the other way thus creating a 0.1 mm tolerance zone. In this case, not having any modifiers, it would be like +/- tolerance; however the GD&T tolerance measurement value would be double of what the delta value is. So let's say you measured the actual length to be 50.005 mm - your GD&T measurement value would be 0.01mm. I hope this helps.
For those interested in a handheld probe that measures hole location on the shop floor, check out ruclips.net/video/HrooZ1jfkT0/видео.html
Amazing
Sir what does that mean for Datuns A,B,C and tolerance valve please sir reply
Srinivas, I am not sure I understand the question. What do you mean by "that" in your first sentence? None of the information in this presentation effects the datums. There is a way to "float" the datums but this will be separated presentation. The tolerance is effected by applying either MMC or LMC. Please follow up if this does not answer your question.
@@PawelGorka1thanks sir reply my question . Yes sir you said correct , create one sir with tolerance and datums ,why should take datums, thanks sir
I guess the question is "why do we need the datums?" The datums constrain the part in space. Imagine that you measure the distance of 1.00, in our example. If we are using, for example, a vision system and select the left edge, move over to the hole center to measure the distance, and the part was not aligned ( it was placed on an agle) with the linear movement of the inspection device, such as the vision system, the measurement would not be correct.
@@PawelGorka1 hi sir could you create a video with datums and little bit of knowledge in gd&t, suggest the good book of gd &t please sir
Thanks & regards
Pakala Srinivas
Please explain Why tolerance zone increases with hole size ?
First, let's thnik about why we need the GD&T. It is used primarily in manufacturing so later during the assembly process and the use of the parts, they fit and work together reliably. GD&T helps us to make parts with consistent sizes and/or parts that consistently meet other specifications. In case of this video example, the bigger the hole the easier it is to insert the mating part, hence the hole can be off the perfect location more than if it was smaller. In other words, there is more clearance between the holes and the mating pins when the hole is bigger allowing to compensate for any misalignment. Ofcourse, the tolerances are calculated during the design process, and to explain how they are decided would be a different discussion.
In order to further explain the changing tolerance concept we will look at an example. Let's imagine two square plates. Plate A has two holes, and plate B has two protruding pins. Now, we assemble these parts so that the plate B pins enter holes on the plate A. If the sizes of the holes are a bit large than the diameters of the pins, it is easier to mate these two parts.They fit together without any interfierance.
But, why would we go to all this trouble of allowing for the tolerance to change? We want to make manufacture easy. In manufacturing, easy equals less expensive. In general, when we design parts we want to allow as much tolerance as possible; it facilitates the manufacture. It reduces the manufacturing costs. For example, with large tolerance, the machines used don't have to be very accurate, hence they are less expensive. Or, the process can be faster- time is money.
I hope this helps. Let me know if you need more information.
I really appreciate your answer...
I have another question that
Is there any necessity of third datum and when it is necessary?
Please explain me
The role of the datum in GD&T is to constrain (suspend) and align the part in the space for the measurements.
By definition, the first datum (primary) is a plane, the second one (secondary) is a line, and the third datum (tertiary) is a point.
Therefore, in the example provided in this video, the datum A prevents the part from moving up and down in the plane of screen along the datum B. It also prevents the part from rotating in the plane of the screen as well as in the plane of the face along datum B. Next, the datum B prevents part from moving left and right along the datum A in the plane of the screen. However, there is nothing preventing the part from moving in and out of the screen in direction parallel to the datum A. In addition, there is nothing preventing the part from rotating around the datum B (remember this is the secondary datum -a line).
I admit that I did not put too much thought into placing these datums for this video. My concern was to explain the tolerance. However, you should use all three datums whenever it is possible. Imagine that this part rotates by an angle around the datum B. If you try to measure the 1.00 basic dimension while still looking at the part in the screen plane that distance will be considerably shorter than it is in reality (you could experience that using a vision system if the part does not sit flat on the table due to some burr or debris on the bottom face, for example).
Even though it is very hard to account for every part and every design, once again, one should use all three datums whenever it is possible. However, there are instances where one could not use more than two datums. For example, imagine a tube with a hole drilled perpendicular to the tube’s axis, somewhere along the length of the tube. One end of the tube should be designated as datum A (this needs to be a face), datum B could be designated as the axis of the tube's inside or outside diameter (the secondary datum is a line). However, there is no third datum to be designated - there are no other features that could be used as a datum.
I will try to add video on this subject; however, meantime, I hope this helps
very usefull, thank you very much
My pleasure Charles. I am very happy if I was able to help.
great job. thanks.
Thank you!
great vid
Thank You.
Thanks, this is really worth giving video I got,but no sound.Please add sound.
I don't add sound to my videos, as I think it might be a destruction. When you read you have to concentrate. But it is not to say that I will change my mind in the future. I am happy you found it useful !
Hello Sir, can you please make it in case of a Pin/Shaft. It will be very useful.
I am sorry, but I am not sure what you mean. If you asking for a true position example for a shaft or a pin, the concept is the same as the one for a hole. You just have to realize that the maximum material condition (MMC) for a shaft means that the shaft is at its largest diameter allowed by the tolerance.
Hey man u r hero
(1.51-1.48)+.02.........From where 1.48 Comes Can any one tell me Please. I am Confused.
1.48 is the minimum allowed diameter of the hole. Starting at 50th second of the video, there is the diameter identified with +/- tolerance. Also, at 3 minutes and 17 seconds of the video there is a call out identifying this number. Hope it helps.
MMC of is wrong so one more you clarify me
SUPER sir
yep
No sound.
I did this kind of on purpose. I thought that viewer will have a chance to concentrate more on the content. But I will experiment with sound once I have some time.
+Pawel Gorka
he ment explanation
thanks XD
My pleasure!
MMC is the stupidest thing in American made drawings.
The only video that explains GD & T without confusing the hell out of me. Believe me I've looked at all other explanations. Well done & thank you!