Thank you , though I know these topics . There is something missing in my mind .i waited for the right person(videos in CZcams) who can make me understand. Your videos made me to understand the missing points.i thank you and CZcams for making people with diff IQ levels ,understand topics from experts around the world.take care .. inspire us .. teach us ..be happy bro.
Hello sir,Thanks for the wonderful explanation,i was attended stack analysis training in my office bu that didn't help me to learn much even in basics,i got some over view after watching this video..Thanks for teaching us..
Hello sir, Wonderful! I was always confused with this concept. You were flawless in your explanation. Even though I'm a Automotive engineer pursuing my MS in USA, I'm very humbled to have learnt this concept from you. Kudos to your effort put in! Wish you all the best in all your endeavors.
In last example slot for 1st part is 24+/-2 For 2nd part dim is 20+/-3 So, If 2nd part is produced at dim 23. Then interference will happen. Suppose we need clearance fit, 1) should we adjust our tolerance to 20+/-2 OR 2) Should we change slot width as 24+/-1 Please let me know 1st option or 2nd option is correct. Or else please correct me if my thought process is wrong Sir. Thank you
AT 7:30---It is not sliding fit but a transition fit as shaft & hole diameters are at same dim. We can characterized it as H1h1 Wheareas Min Clearance 0 & max 0.003.
@@TheEssenceofknowledge But dear sliding fit fall under clearance fit. So i doubt it is a transition fit... By the way thanks for uploading good content :)
Thank you very much sir.... I got some basic idea about stack up.. I am expecting more classes and examples like used in real time... Hope you will be uploaded.... Once again tq.....
Great Video Sir! Small doubt- In last eg 27:17 there will not be any effect of perpendicularity tolerance in vertical direction but you considered it. Why?
Why Chain dimensioning not provided with a close loop? Why the dim 10+-0.5 is not useful in determining the thickness? For vertical gap: 6+-3 i.e gap is between 9 to 3mm and horizontal gap: 3+-3, i.e gap is between 6 to 0mm. In the last example with GTol. it shows interference of 1mm, how to avoid the interference in such case?
Hi Parag, any dimension system that give more tolerance deposit to a important feature should not be used. From start of loop to close loop, what ever dimension given in drawing must be used, using excess dimension will result wrong analysis. Yes correct, you can check last video in stack up series for solution and another example to solve. If any interference, it can be eliminated by making more precise dimension or best is to change any dimension if we are in design phase. let me know if this clarifies.
Hi, one doubt in 29.00 part using perpendicularity in stack up, Perpendicularity make sure a surface is perpendicular to datum hence does not affect the vertical dimension so how can it be considered in this stack, If your find the stack up in horizontal direction then it perpendicularity of the surface affect you gap
Hello Sir, sorry to say but maybe I have confusion I have gone through your video wherein you said that VC for shat is the worst condition as it is the biggest size of the shaft but as I know biggest dia of the shaft is not the worst scenario if dia of shaft is larger then you can reduce it to required size as there is a material available for machining. The worst situation will occur if the shaft is manufactured at LMC, as there is no material is available for machining further.so instead of saying the VC is the worst situation for the shaft, I would say it is a good scenario for the shaft. might be I am wrong, It would be great if you clear this doubt. have a good day to you, sir.
Tolerance stackup is done for assemblies. And worst case for assembly will be shaft bigger and hole smaller. Tolerance stackup is study when u dimensioned the component and completed the design, it will check if there will be any issue during assembly even all component with in their tolerance zone.
@@TheEssenceofknowledge Thank you very much, sir, for your valuable revert. if still there is any I will come back to you. I have doubts still of Bonus tolerance and its addition into the RC when the modifier is added to the tolerance zone.
thank you very much.. I have completed welding lecture, 2 lecture of GD&T and 2 lecture of Stack-up one by one and keep going. I want to tell you your video gave me confidence to learn these topic which i was thinking to learn from last 1 yr and always thought that these topics can not be understand by me as i have no practice knowledge etc. Thank you sir again, i will complete all videos soon. Please guide me how can i get knowledge of material, machining process etc as i have 4yr experience in Designing software only but 0 in practical experience. I got stuck and no way to come out everyone needs the practical and other knowledge n experience even to get start in manufacturing industry :(
Trilok, For material knowledge, just start exploring whatever material you get through. Just read it's properties, go through alloying elements like nikel adds toughness and thermal resistance, cobalt adds red hardness etc.. reading 30 mins a day will make you more confident.. let me know if you need anything specific.. thank you for watching videos..
Very useful video for beginners like me. But I do not understand the example at the end. I understand how GTOL can enlarge outer boundary for block/shaft at MMC, and that represents VC - that's ok with me. But Sir, how GTOL can reduce the size of block/shaft at LMC (that is how you explain RC)? It will never happen if we produce part with respect to drawing requirements. Parallelism tolerance 1mm do not allow us to produce part 17mm if we have dimension tolerance 20+/-2 In your example max gap would be 26-17+9. But that is not the truth, as I understand
It is a RC and VC both virtual boundary only. At any cross section size tolerance must be followed. Suppose the saft, vc condition is what is worst case hole diameter needed to accommodate when it is at MMC and dislocated by Gtol. Hole size required will be MMC shaft +Gtol to accommodate it any scanario. Parallelism can affect boundary if applied to feature of size otherwise it do not controls location. Next week I have webinar on this.. I will share to you if you wana join. 🙏Thank you
In case of geometric tolerance , please confirm it applicable when modifier is given because when modifier is not given it is af RFS. Waiting for your reply.
When modifier given it gives additional bonus tolerance and if no modifier it is based on RFS but both must be considered in tolerance stack up analysts. Let me know if it clarifies. Please let me know further queries.
Rules.. The dimensions which we define in drawings can only be used in stackup. It should be in one direction horizontal or vertical. To go from one component to other there must be surface to surface contact or hole aligned.
Hello Sir, thanks for the video, just one question, I didn't understand how the perpendicularity feature affected the length of the block (during the stack up analysis) using the "A" datum at the bottom of the piece, probably the A datum should be placed in the vertical face to consider it? thanks in advance.
Alfredo Gutierrez , yes correct. The datum is on vertical face. Not on the face on which it is resting. Otherwise it should be parallelism. My mistake, it seems it is on bottom face. Sorry for misunderstanding. Thanks you!!
Dear sir, could you please provide a solution for the example that you have shown in later part of this session which is for exercise. I wish to compare it with my results. Thanks in advance!
Nilesh, please try to go through Gd&t Lecture 10. It explains LMC modifier. In that case we get additional tolerance when feature departs from LMC and we get max bonus at MMC.
@@TheEssenceofknowledge Thank you sir! What about the perpendicularity tolerance in the above example. It doesn't affect the size. Then why do we calculate VC and RC?
@@nileshrathod3153 yes it should have been parallelism tolerance here. But it doesn't means if there is tolerance of orientation no need to calculate vc rc. We need to do so. As these tolerances are applicable at RFS and mmc lmc bases. Please see GD&Tlect 7for more clarification. Please let me know further queries.
In the given example that was asked to practice there are both vertical and horizontal dimension. so, do i need to take two tables for calculating or in one table it need to done? if in one table it need to be calculated then how can i co-relate the tolerance values to the dimension. please clarify.
Please give more examples of stack calculation with GTOL applied.How to find VC and RC in case of modifiers(MMC,LMC) used and different GTOL symbols like profile tolerance,runout. Also let us now the effect of Datum shift in our calculation.Looking forward to your Reply.
Dear Sir, Great video. More information in a sharp manner. God bless you for sharing the knowledge. Have a doubt, in How GTOL affects the Stack up Analysis - normally in GD&T, Virtual Condition and Resultant condition are used in FOS (Shaft, Hole, slot) & not in planner surfaces. Since its for Stackup do we use VC & RC here?
We calculate VC and RC case to case.. it depend on the Gtol and how it is used. VC is most important aspect. We need min hole equal to VC of the shaft. And VC is MMC + Gtol for shaft and same for shaft. Let me know if this helps..
It can't change hight but if it applied at mmc or RFS basis, form can go beyond Limit of size. In that cases we need to consider that. In this example I have just shown how to consider gtols in stack. I am about to post orientation tolerances in GD&T series of lectures. You will get to know more. Let me know if any more questions and and you need more explanation about it.
Hi good video thank you for your clear explanation...i have a dout when FOS deflects from MMC/LMC bonus tolerance is available to which the bonus tolerance is added...
Suppose we have given position tolerance .1 to a hole at mmc modifier. Hole size 10+-1. When hole will be at mmc i.e. 9 it become critical and its axis can move only .1 diametrically. If it departs from mmc to lmc ie from 9 to 11. It will have have bonus positional tolerance. Suppose manufacture dim is 10 hole axis can move 1.1 diametrically. 1 is amount of departure and .1 is positional tolerance.
Thanks for your responce Simply can we say that the amount of deflected value should add to geometrical tolerance present in FCF.please correct me if iam wrong...
enaganti purushotham , suppose you given base line or chain dimension on drawing. You can give xy as reference dimension not a strong dimension as drawing is already fully defined. While you assembly the component, in a case suppose the xy play a role. It has seating face. Then xy may matter. It is just a example of tolerance sink. When we give feature dimensions, it's tolerance going to dump on a feature. In that case we require to control that. Let me know further query.
@@TheEssenceofknowledge vertical i am getting answer 6(+or- 3)...Horizontal i am getting 3(+ or -3)....From this answer hw can i find stack gab ie 6-0 in horizontal and 9-3 in vertical???
6+/-3 in vertical direction &
3+/-3 in horizontal direction
Correct
Values after doing the stackup for given assembly are: 6+/-3 in vertical direction &
3+/-3 in horizontal direction
Yes correct.
Vertical slot 6+/-3
Horozontal slot 3 +/-3
Thanks you very much sir
Correct
Thank you , though I know these topics . There is something missing in my mind .i waited for the right person(videos in CZcams) who can make me understand. Your videos made me to understand the missing points.i thank you and CZcams for making people with diff IQ levels ,understand topics from experts around the world.take care .. inspire us .. teach us ..be happy bro.
Thank you!
Hello sir,Thanks for the wonderful explanation,i was attended stack analysis training in my office bu that didn't help me to learn much even in basics,i got some over view after watching this video..Thanks for teaching us..
good....
Hello sir,
Wonderful! I was always confused with this concept. You were flawless in your explanation. Even though I'm a Automotive engineer pursuing my MS in USA, I'm very humbled to have learnt this concept from you. Kudos to your effort put in! Wish you all the best in all your endeavors.
Aditya, Thank you!!
In last example slot for 1st part is 24+/-2
For 2nd part dim is 20+/-3
So, If 2nd part is produced at dim 23. Then interference will happen.
Suppose we need clearance fit, 1) should we adjust our tolerance to 20+/-2 OR
2) Should we change slot width as 24+/-1
Please let me know 1st option or 2nd option is correct.
Or else please correct me if my thought process is wrong Sir. Thank you
Nice, no such videos available on CZcams. Thank you very much.
Thanks for the simplest and easiest way for explaining
AT 7:30---It is not sliding fit but a transition fit as shaft & hole diameters are at same dim. We can characterized it as H1h1 Wheareas Min Clearance 0 & max 0.003.
Yes, that is why it is sliding fit fit me otherwise could have been a clearance fit.
@@TheEssenceofknowledge But dear sliding fit fall under clearance fit. So i doubt it is a transition fit... By the way thanks for uploading good content :)
@@CadCamCaeWithYogesh thank you, I will keep this in mind. Thanks.
Rhe variances add as the sqrt of the sum of the squares of the variances... And variance can be assumed to be 1/6 of the range of each dimension/
Work case has been explained here
Thank you, I will understand the stock up analysis.
Thank you for this session. It was very informative in understanding Tolerance Stackup.
Thank you very much Brother ,now i clearly understood the concept of stock up analysis.
Thank you
Thank you very much sir....
I got some basic idea about stack up..
I am expecting more classes and examples like used in real time...
Hope you will be uploaded....
Once again tq.....
Sure
Very good explanation with examples sir...
Great Video Sir!
Small doubt- In last eg 27:17 there will not be any effect of perpendicularity tolerance in vertical direction but you considered it. Why?
Yes, it should have been parallelism.
correct...I have the same doubt...No effect of perpendicularity
28:13 what is the difference of applying gdandt below dimensions and attach with extensions line of dimensions
Very clear and simple explanation, easy to understand. Thank you
sreejith pv Thanks, Let me know if any query.
Like toh banta hai
Why Chain dimensioning not provided with a close loop?
Why the dim 10+-0.5 is not useful in determining the thickness?
For vertical gap: 6+-3
i.e gap is between 9 to 3mm and
horizontal gap: 3+-3,
i.e gap is between 6 to 0mm.
In the last example with GTol. it shows interference of 1mm, how to avoid the interference in such case?
Hi Parag, any dimension system that give more tolerance deposit to a important feature should not be used.
From start of loop to close loop, what ever dimension given in drawing must be used, using excess dimension will result wrong analysis.
Yes correct, you can check last video in stack up series for solution and another example to solve.
If any interference, it can be eliminated by making more precise dimension or best is to change any dimension if we are in design phase. let me know if this clarifies.
Good learnings for beginners, Thank you.
Thank you
Hi, one doubt in 29.00 part using perpendicularity in stack up, Perpendicularity make sure a surface is perpendicular to datum hence does not affect the vertical dimension so how can it be considered in this stack, If your find the stack up in horizontal direction then it perpendicularity of the surface affect you gap
Yeah...I too have same doubt
Great Video !! clearly explained right from basics...
Why you have changed tolerance from 1.5 to 1.
In chain dimensioning.
I have not changed that.. it is 1.5 only but just compared to base line dimensioning in which tolerance was 1 for same length
Thanks a lot sir, its very much helpful...
Hello Sir,
sorry to say but maybe I have confusion I have gone through your video wherein you said that VC for shat is the worst condition as it is the biggest size of the shaft but as I know biggest dia of the shaft is not the worst scenario if dia of shaft is larger then you can reduce it to required size as there is a material available for machining. The worst situation will occur if the shaft is manufactured at LMC, as there is no material is available for machining further.so instead of saying the VC is the worst situation for the shaft, I would say it is a good scenario for the shaft.
might be I am wrong, It would be great if you clear this doubt. have a good day to you, sir.
Tolerance stackup is done for assemblies. And worst case for assembly will be shaft bigger and hole smaller. Tolerance stackup is study when u dimensioned the component and completed the design, it will check if there will be any issue during assembly even all component with in their tolerance zone.
@@TheEssenceofknowledge Thank you very much, sir, for your valuable revert. if still there is any I will come back to you. I have doubts still of Bonus tolerance and its addition into the RC when the modifier is added to the tolerance zone.
Yes sure.
Thanks sir
Nice explained the whole concept
Thank you so much for your videos!
@27:14 the answer for example is 6+/-3 (vertical) & 3+/-3 (horizontal) .. Is it right sir?
Correct
Great video, thanks for sharing your knowledge...
Thank you so much sir... 🎉
thank you very much.. I have completed welding lecture, 2 lecture of GD&T and 2 lecture of Stack-up one by one and keep going. I want to tell you your video gave me confidence to learn these topic which i was thinking to learn from last 1 yr and always thought that these topics can not be understand by me as i have no practice knowledge etc. Thank you sir again, i will complete all videos soon. Please guide me how can i get knowledge of material, machining process etc as i have 4yr experience in Designing software only but 0 in practical experience. I got stuck and no way to come out everyone needs the practical and other knowledge n experience even to get start in manufacturing industry :(
Trilok, For material knowledge, just start exploring whatever material you get through. Just read it's properties, go through alloying elements like nikel adds toughness and thermal resistance, cobalt adds red hardness etc.. reading 30 mins a day will make you more confident.. let me know if you need anything specific.. thank you for watching videos..
Answer for given example is 6 plus or minus 3 mm.
Correct
Excellent
Excellent sir
Very useful video for beginners like me. But I do not understand the example at the end.
I understand how GTOL can enlarge outer boundary for block/shaft at MMC, and that represents VC - that's ok with me.
But Sir, how GTOL can reduce the size of block/shaft at LMC (that is how you explain RC)?
It will never happen if we produce part with respect to drawing requirements.
Parallelism tolerance 1mm do not allow us to produce part 17mm if we have dimension tolerance 20+/-2
In your example max gap would be 26-17+9. But that is not the truth, as I understand
It is a RC and VC both virtual boundary only. At any cross section size tolerance must be followed. Suppose the saft, vc condition is what is worst case hole diameter needed to accommodate when it is at MMC and dislocated by Gtol. Hole size required will be MMC shaft +Gtol to accommodate it any scanario. Parallelism can affect boundary if applied to feature of size otherwise it do not controls location. Next week I have webinar on this.. I will share to you if you wana join. 🙏Thank you
@@TheEssenceofknowledge Thank you for quick response and your willingness to help. I will appreciate advantage of taking part in your webinar.
@@tomaszz4807 thanks, it's on 3rd August. I will share the link.
teams.microsoft.com/dl/launcher/launcher.html?url=%2F_%23%2Fl%2Fmeetup-join%2F19%3Ameeting_ZTc5NWQ5YWQtNjMwZS00OTE2LWE4OWEtM2IwMDBhMTU4NGQz%40thread.v2%2F0%3Fcontext%3D%257b%2522Tid%2522%253a%2522b0f69cc7-03f1-42a0-8032-afbc4ed9fca8%2522%252c%2522Oid%2522%253a%2522d57eabca-c42a-418c-a55d-cb2a912b5338%2522%257d%26anon%3Dtrue&type=meetup-join&deeplinkId=055c3bd1-b2ec-4067-8603-058df0803a75&directDl=true&msLaunch=true&enableMobilePage=true&suppressPrompt=true
Microsoft Teams Link for tomorrows Webinar, 7.00 pm IST
very nice...
u r a legend
Hello Sir, If there is variation in center to center position of mounting holes and it goes out of tolerance limit in such case what should be done?
Thank you, it is very good explanation
In case of geometric tolerance , please confirm it applicable when modifier is given because when modifier is not given it is af RFS. Waiting for your reply.
When modifier given it gives additional bonus tolerance and if no modifier it is based on RFS but both must be considered in tolerance stack up analysts. Let me know if it clarifies. Please let me know further queries.
can please explain why should i consider loop A material in baseline dimension, when i can close the loop from X to Y.
Rules.. The dimensions which we define in drawings can only be used in stackup. It should be in one direction horizontal or vertical. To go from one component to other there must be surface to surface contact or hole aligned.
Hello Sir, thanks for the video, just one question, I didn't understand how the perpendicularity feature affected the length of the block (during the stack up analysis) using the "A" datum at the bottom of the piece, probably the A datum should be placed in the vertical face to consider it? thanks in advance.
Alfredo Gutierrez , yes correct. The datum is on vertical face. Not on the face on which it is resting. Otherwise it should be parallelism. My mistake, it seems it is on bottom face. Sorry for misunderstanding. Thanks you!!
Thank you Sir for your quick response, Kind regards from Mexico!
Welcome and greetings from India :-)
Good catching...
The Essence
Wow tq sir
Very good and detailed lecture 👍😊
Thanks you!!
Hi please clarify me is our VC size and functional gauge(mating part) size are both same.
VC of shaft is functional guage size for go gauge for required hole.
Nicely explained, thank you
Thank you so much,you shared good stuff.....
Dear sir, could you please provide a solution for the example that you have shown in later part of this session which is for exercise. I wish to compare it with my results. Thanks in advance!
Sujay, if you want solution early please share your mail id. I will provide the solution. Or will create a video of solutions.
@@TheEssenceofknowledge sujaybhudhar@gmail.com
I have sent you the details. Please let me know queries if any.
great explanation sir, keep it up
Awesome..
Very good
Thank you the lecture was very good 👍
sir can you explain how LMC modifier for shaft will give bonus tolerance? and how LMC modifier requires variable gauging?
Nilesh, please try to go through Gd&t Lecture 10. It explains LMC modifier. In that case we get additional tolerance when feature departs from LMC and we get max bonus at MMC.
@@TheEssenceofknowledge Thank you sir! What about the perpendicularity tolerance in the above example. It doesn't affect the size. Then why do we calculate VC and RC?
@@nileshrathod3153 yes it should have been parallelism tolerance here. But it doesn't means if there is tolerance of orientation no need to calculate vc rc. We need to do so. As these tolerances are applicable at RFS and mmc lmc bases. Please see GD&Tlect 7for more clarification. Please let me know further queries.
In the given example that was asked to practice there are both vertical and horizontal dimension. so, do i need to take two tables for calculating or in one table it need to done? if in one table it need to be calculated then how can i co-relate the tolerance values to the dimension. please clarify.
When direction changes loop diagram changes. So we need to do two tables.
Please give more examples of stack calculation with GTOL applied.How to find VC and RC in case of modifiers(MMC,LMC) used and different GTOL symbols like profile tolerance,runout. Also let us now the effect of Datum shift in our calculation.Looking forward to your Reply.
Mrinal Singh , yes sure.
Hi Sir, i have a question how to solve cumulative tolerance by sure fit law and truncated normal law
I will get back on this soon
Dear Sir, Great video. More information in a sharp manner. God bless you for sharing the knowledge.
Have a doubt, in How GTOL affects the Stack up Analysis - normally in GD&T, Virtual Condition and Resultant condition are used in FOS (Shaft, Hole, slot) & not in planner surfaces. Since its for Stackup do we use VC & RC here?
We calculate VC and RC case to case.. it depend on the Gtol and how it is used. VC is most important aspect. We need min hole equal to VC of the shaft. And VC is MMC + Gtol for shaft and same for shaft. Let me know if this helps..
tutorial answer are 6-0 and 9-3 horizontal and vertical respectively.. its correct?
thanks for great lecture..
abdullah shaikh, yes you are correct.. nice
I can't get horizontal value 9.
Can you please explain
Laxman Rangisetti, Please give me your mail id.. I will share you snap..
laxmanrangisetti@gmail.com
Laxman, I have shared you the details.
it was nice explanation but one thing bothering me is that, How does the perpendicular Gtol affects the height of the part ?
It can't change hight but if it applied at mmc or RFS basis, form can go beyond Limit of size. In that cases we need to consider that. In this example I have just shown how to consider gtols in stack. I am about to post orientation tolerances in GD&T series of lectures. You will get to know more. Let me know if any more questions and and you need more explanation about it.
Thank you sir for clearing the doubts..
Thank you!
fabulous!
Thanks
super knowledgeable sessions bro
Thanks
Need more lectures on stack up analysis.
Sure will do. If you have any example of suggestion i can plan on that
Hi good video thank you for your clear explanation...i have a dout when FOS deflects from MMC/LMC bonus tolerance is available to which the bonus tolerance is added...
Suppose we have given position tolerance .1 to a hole at mmc modifier. Hole size 10+-1. When hole will be at mmc i.e. 9 it become critical and its axis can move only .1 diametrically. If it departs from mmc to lmc ie from 9 to 11. It will have have bonus positional tolerance. Suppose manufacture dim is 10 hole axis can move 1.1 diametrically. 1 is amount of departure and .1 is positional tolerance.
Let me know if this answers your question..
Thanks for your responce Simply can we say that the amount of deflected value should add to geometrical tolerance present in FCF.please correct me if iam wrong...
@@SudheerKumar-ie4ep yes correct.
sir,how to decide linear tol valeu...like as here you have taken .like .05mm
Hi Vasim, sorry for late response. I did not got your question. Would you please clarify more. Thanks
Hi, Sir... Can I know why you have calculated xy value on component ? How it will effect manufacturing ?
enaganti purushotham , suppose you given base line or chain dimension on drawing. You can give xy as reference dimension not a strong dimension as drawing is already fully defined. While you assembly the component, in a case suppose the xy play a role. It has seating face. Then xy may matter. It is just a example of tolerance sink. When we give feature dimensions, it's tolerance going to dump on a feature. In that case we require to control that. Let me know further query.
how do i put tolerance for individual part by stack up.?
Sankar S, we need to convert all tolerances to symmetric system and put them in to stack up table. Let me know if anything specific.
super bro
Hi sir, when you are uploading lecture 3 & 4.
Basavaraj Suma , it will be within 2-3 days. In process.
verry nice
needs volume
This is very nice. In ur example Horizontal stack gab is 6-0 and vertical is 9-3... is it correct r not
saran S , it is correct.. nice
thanks to reply
Hi machan...
@@TheEssenceofknowledge vertical i am getting answer 6(+or- 3)...Horizontal i am getting 3(+ or -3)....From this answer hw can i find stack gab ie 6-0 in horizontal and 9-3 in vertical???
@@SabariPrabakaran3434 6+3 = 9 and 6-3 = 3 same for other
Anyone working with simtol...... ❤
hi sir need solution for the problem
Your mail ID please , I will forward solution.
Hi, Sir... If you don't mind please give practical examples...
Sure, will do that.
Thank for reply and will be waiting for your practical examples...
can you speak english please?
That is good.. I have failed multiple time in English. Can you be my teacher.
Thank you sir