foreign hello newtonians in this video we are going to learn about dimensions on engineering drawing we are going to look at what dimensioning is what are the elements of the dimensions and what rules for dimensioning are furthermore we are going to look into dimensioning methods and look what functional and non-functional dimensions are imagine that you are buying a new cabinet online you are looking at the pictures of the cabinet and you are satisfied with its form and Aesthetics and you would like to buy it as you are limited with the space you are looking for the dimension of the cabinet to see if it will fit in your space at least what you will look for is width depth and the height of the cabinet the next logical step is to measure your free space and compare it with the defined cabinet dimensions if the cabinet does not fit in your free space you will not purchase this cabinet the similar thing we are doing with the components that we are Manufacturing when we create a drawing of the 3D object we create all the necessary views orthographic views and or pictorial views for its unambiguous representations and we add Dimensions to it then we send a strong to our supplier to manufacture it after components have been manufactured we would or our supplier inspect the component's dimensions to see if they are created according to our drawing specification in case some of the dimensions are outside of the specified Dimension supplier we'll have to rework the component or create a new one properly defined Dimensions ensure that everyone involved understands the size shape and tolerances of the object being depicted furthermore they guide machinists and fabricators in determining the appropriate tools techniques and tolerances required to produce the part accurately accurately defined Dimensions help convey the design intent it provides information about critical features relationships between different parts and important geometric characteristics dimensioning for those reasons is the most important part of the drawing creation the dimensioning can get very complex as the complexity of our product gets higher you could have 10 or more different components as a part of one complex assembly these components could be fixed to each other while others could move in respect to each other defining proper Dimensions to be inspected and defining the proper tolerances is one of the hardest parts of creating the engineering drawings these Concepts will be explained in another video because they are so important that they will need a few videos to be completely clarified but before we go to these complex topics first we must learn the basics elements of dimensions as we previously mentioned mentioning is necessary to define the shape and form of an engineering component in other words with the use of dimensioning techniques on the engineering drawings we Define physical boundaries of the component like size and location of the different features on a drawing of thin lines with the arrows on the sides and the number in the middle or on side is how we represent dimensions on the engineering drawings the rules for the dimensioning are defined by ISO 129 to 1 2018. in the real world most engineering companies use CAD software for Designing products and for creating engineering drawings most of CAD software already contains different standard rules for creating drawings with that being said we will not dissect every rule to its core at this point I think that it is good enough for you to learn the basic terminology of dimensioning and then move to perfect your craft of dimensioning drawings unambiguously extension line Dimension line nominal value and terminators let us now look at the most important elements of dimensions extension lines are drawn perpendicular to the feature that is being dimensioned Dimension line the dimension line is perpendicular to the extension line and above this line the nominal value is shown nominal value represents the nominal value of the dimension I.E it represents a physical value of the feature in specific units the nominal value is always above the dimension line and it isn't a natural scale one colon one the tolerances are always added to the nominal value terminators on the engineering drawing we are using Terminators to clearly represent the end of the dimensional lines in ISO 129 to 1 2018 you can see recommended types of Terminators as you could imagine the sizes and shapes of all of these elements are defined by ISO 129 to 1 2018. but as I already told you all of these rules are already Incorporated in the CAD software and as long as you choose your preferred standard in the software settings you should be fine in addition to the elements mentioned before we can also encounter the following elements leaderline used to direct a dimension note or symbol to the intended place on a drawing reference line is created in conjunction with the leader line property indicators symbols are used to replace words to simplify the drawing property indicators symbols are diameter radius square spherical diameter spherical radius Arc Length thickness of thin objects depth cylindrical counterbore and countersink reference letter is used when we have alternate dimensions for the different usage for example we have the exact geometry of the plate with two different hole diameters in that case we don't have to create a new drawing with the different hole sizes but we can mark this Dimension with the capital letter then the letter would be placed in the table and the values for the different hole sizes rules for dimensioning while defining dimensions on the drawing we should keep in mind rules for dimensioning all dimensions on the drawing should be in the same specified units example millimeters if we use other units for specific features the corresponding unit should be written with the nominal value all the relevant dimensions of the object should be defined on the drawing each feature is dimensioned only once on the drawing if we need to Dimension something twice for informational purposes we can use auxiliary dimensions the auxiliary dimensions are placed into parenthesis the comma should be used as a decimal separator dimensioning methods now when we understand the basics let us investigate the methods we can use when we are dimensioning the shape and form of our objects chain dimensioning chain dimensioning is the method where dimensions are placed from one feature to another feature this method is commonly used we should keep in mind that each tolerance Builds on the next one this method is usually used when the parts function requires that the features are related to each other when using chain Dimensions it is important to provide clear references and maintain a logical and consistent order proper alignment and spacing of dimensions are essential to avoid confusion and ensure the accurate interpretation of the chain of dimensions parallel dimensioning in the parallel dimensioning method all the dimensions originated from the same base this method is commonly used for machine parts also it is used when the size or feature should be controlled from a common reference plane and less tolerance buildup IS desired when employing parallel Dimensions it is important to ensure that the dimension lines are not excessively long or extend beyond the feature being dimensioned proper spacing alignment and consistent placement are key considerations to maintain a clear and organized drawing running dimensioning the running dimensioning is exactly the same as a parallel method but a different graphical representation is used dimensions are placed in a continuous manner along an uninterrupted length or feature typically along the edge or Center Line of an object running dimensions are commonly used for Dimensions along linear features such as lengths widths and Heights it is particularly useful when there are numerous repetitive features or when Dimensions need to be placed in a compact and organized manner the starting location of the dimension is defined with the origin symbol combined dimensioning the combined method is the practice of utilizing multiple dimensioning methods within a single engineering drawing by combining different methods within the drawing we aim to optimize Clarity readability and space utilization while providing comprehensive and accurate dimensions for different aspects of the design equally spaced features by combining different methods within the drawing we aim to optimize Clarity readability and space utilization while providing comprehensive and accurate dimensions for different aspects of the design when features are equally spaced we can simplify dimensioning one and write how many times it is repeated repeated features when we have multiply features with the same dimensions we can Dimension only one feature and note how many times this Dimension is repeated symmetrical object when we have the dimension symmetrical object we can simplify the drawing by creating only half of the object and indicate the symmetry line dimensioning of restricted areas when we need to Define special requirements to a restricted portion of the feature for example surface hardening we have to indicate that area on the drawing dimensioning chamfer functional and non-functional dimensions when we are dimensioning an object naturally some Dimensions will be more important than others some Dimensions will be critical to the correct functioning of the component and these are called functional dimensions other dimensions will not be critical to correct functioning and these are called non-functional dimensions functional dimensions are obviously the more important of the two and therefore will be more critical when making decisions about the dimension value dimensioning on the engineering drawing is probably the most challenging part of the drawing creation you can see that there are many dimensioning basic rules and that is not even the hard part the next step to upgrade your dimensioning skills is to learn about the tolerances with time and practice these rules will embed in your work routine and you will not think about them when that happens make sure to re-watch this video as a real expert you want to make sure that you are communicating the right message every time someone checks your drawing you are not only communicating design details on your drawing you also communicate your expertise and your company brand with that being said make sure that you always communicate the right message did you learn anything new in this video let us know in the comments below do you like our videos then give us a thumb up comment and share with your friends colleagues and on your social media channels and if you want to become a part of the newtonians make sure to subscribe to our Channel