GD&T Tutorial 13A : Rule #1
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- Опубліковано 28 сер 2024
- GD&T Tutorial : Rule #1 : Part 1 - In this Video, You will get the explanation of Rule #1 in Geometric Dimensioning and Tolerancing Tutorial
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Rule #1 Statement
Where only a tolerance of size is specified, the limits of size of an individual regular feature prescribe the extent to which variations in its geometric form as well as in its size are allowed
Rule #1 is also called as
1. Perfect Form at MMC Rule
2. Envelope Principle
3. Individual FOS Rule
Rule #1 Requirements
1. The Actual Local Size of the regular FOS at each cross section shall be within the specified size tolerance
2. Where a regular FOS is produced at MMC. It must have perfect form
3. When the actual local size of a regular FOS departs from MMC towards LMC, a variation in form is all0wed equal to the amount of departure.
4. There is no requirement for a perfect form boundary at LMC. A part produced at its LMC limit of size, is permitted to have maximum form variation up to MMC Boundary
5. Rule #1 applies to regular Feature if size only.
Rule #1 Does not control the location, or orientation of feature of size, hence it is called Individual Feature of Size Rule.
Rule one is not applicable to the indicated dimension because the part produced at MMC should be in perfect form.
If I'm wrong please correct me
Partially Correct, Rule #1 can not be applied to Irregular FOS, the Arrow is pointing to Irregular FOS
@@PalaniKailash sir how can I know that the shown picture is having irregular FOS. because it is not showing any tolerance.
Please view my video on Feature of Size, in which i have explained about identifying irregular feature of size type A.
The arrow in the drawing is pointing to irregular feature of size type A in the question asked in this video.
How I have answered your question
@@PalaniKailash thank you for the quick response
I have watched the video.
So it can't be measured by using vernier caliper because it is not having a perfect circularity.
this is Irregular FOS because there are break in internal dia (regular FOS, ) by tooth.
You are doing great Job sir. I become your fan sir. 😊😁
Keep watching
Great sir thanks 👍🙂😀😃😊
HI Palani, I think the answer is no, because the indicated diameter is an irregular FOS and the rule # 1 only applied in regular FOS. I will appreciate your opinion or correction.
You are Right
Hope, now you have clarity on Rule #1.
I will upload video on Rule #2 Shortly
Feel free to ask for Any other topic
No rule 1 does not apply on this as there is no control of inner profile dia 59/61 with respect to outer diameter. So inner profile should be controlled concentrically from outer profile. Otherwise during its mating with mating part there may be problem and if it is not concentrically controlled then teeth size can vary because of shifting of centres.
Rule#1 doesn't apply to the figure shown in the question as it is an irregular FOS and rule#1 is applicable to regular FOS
You are right, Rule #1 does not apply
Answer is no, since it is not a regular feature of size.. Correct me if I'm wrong
Hi Sir, I think it is not applicable for Rule-1, as the feature is an irregular FOS type A and the Rule 1 is applicable for regular size.
Imagine a Dia 60 H7 ( 60.000 /60.045 ) hole is to be controlled for cylindricity. As per the rule 1, if the hole is at MMC, its form must be perfect. Further, if the hole departs from MMC, some deviation at cylindricity can be allowed depending upon the actual size of the hole, but not beyond 60.045. All this will mean that the second chamber of the feature control frame has to indicate 0.00 permissible tolerance with M modifier. But the M modifier is not allowed for cylindricity. This characteristic allows only RFS modifier. How to resolve this controversy ?
To answer the question at the end of this video: I think not - Simply because the Diameter of 69/59 is stated as a "Basic Dimension" and is not associated with a FCF denoting which tolerance type, I.E. Cylindricity, Circularity with any modifiers (or lack of) such as MMC or LMC - Assuming it is RFS is a bad assumption when the entire format is outside of a Feature Control Frame as a GD&T associated dimension should be -
Sir in the question the said feature of size can be measured by an vernier callipers. So how it is an irregular feature of size. we dont need an actual mating envelope to measure the diameter
can you be specific please, because, your question is not clearly understood by me
Your explanation good
Rule no 1 dose not apply in this because, this is not regular feature of size. Diameter can be measured at the tooth, but its not regularu.
the final ques- ans is no, rule #1 wont applied to that shape. because it is irregular feature of size and rule 1 applies to regular FOS
Answers in this video
ua-cam.com/video/SoEwGp1vHG0/v-deo.html
Hello sir,
Limit dimensions are given, it means rule no 1 is applicable. we can apply.
It will be nice if you could reference which statement/sentence/section was referred to for all the requirements stated in the video. Thank you for the videos. Good job.
Thanks for the suggestion, will consider in next coming videos
Because given geometry is not a regular feature of size
Rule no1 doesn’t apply in this case cause it’s not a feature of size.
NO...
and its a regular feature of size by seeing but it's a imaginary ( pcd ). rule no-1 does not apply on imaginary of feature of size
correct.. my answer
the question in this video is already answered, please see my previous comments
Rule one will not be applicable because it is irregular feature of size dimension
Since it is an Irregular FOS rule #1 can't applicable
thank you very much for the videos
👍
hi palani sir, as we know the feature (regular) can have maximum form deviation when it is at LMC, is it possible to have all the form deviations at maximum level in LMC, like max straightness error + max cylindricity error
if i have understood your question properly. for one limit of size dimension, if the size is at LMC, all the form errors will be at its Max condition
Great
Thank you so much for video
welcome
I think much more detail explanation of the statement would be better. If it hurts sorry for that
more information is given in part 2, hope you have over looked it while putting your comments
What if the part is completely straight with LMC. will this obey rule 1
Dose the Rule #1 applies to internal dimensions like holes, slots etc? If then things are opposite when it comes to FOS, MMC & LMC?
yes, Rule #1 applies to both external and internal FOS dimensions
The arrow show only feature not the feature of size. Rule 1 applied only to regular fos.
ua-cam.com/video/SoEwGp1vHG0/v-deo.html
check this video for answer
Any reply to my earlier query raised six months ago?
No bcoz its irregular shape.
Your answer is right but the reason is not right.
This is an example of Irregular Feature of Size and Rule #1 applies to Regular Feature of Size Only
Where can i get pure basic knowledge about Gd &t when i am not clear about what is meaning for feature,mmc,lmc.....please i want to learn from zero...
If you are looking for book
You can download from
prolotek.com/downloads/
If you are looking for training contact me on 9886371971
@@PalaniKailash sure sir..
Sir can you please leave the answer with video. Because I can't understand answer clearly
separate videos are uploaded for answers, please chck
Why MMC envelope is taken for Rule 1 ?
When there is no GD&T control applied, then with limits of size, if we have to ensure assembly between two mating parts, then that is possible only when we consider MMC boundary.
For Example:
Take two parts
01 Shaft with upper limit Dia. 20 - MMC will be 20
01 Bush with lower limit Dia. 20 - MMC will be 20
These two parts can be assembled with '0' clearance
If either the shaft or the hole exceed the MMC boundary, then assembly is not possible.
@@PalaniKailash great . Thanks sir
No