Sizing Cylinders and Hole Dimensions in Technical Drawings

Technical drawings are a common language among engineers who are dealing with some professions. If an engineer or technician creates a detailed technical drawing of a part, another engineer or technician will understand all the information on that paper regarding that part, on the other side of the world. A good engineer must know this common language! 

But this technical language has its common characteristics and rules just like other languages. You can find instructive content about technical drawing on! 

How To Size Cylindrical Dimensions in Technical Drawings?

In most technical and engineering structures, cylindrical shapes are very common such as crankshafts of vehicles, storage tanks, gear mechanisms, etc. 

When you are showing these cylindrical shapes, these rules are important; 

  • It’s very important to show the diameter rather than the radius of the cylindrical shape. 
  • Show the size of the dimension in the view where the cylindrical shape appears as a rectangle. 
  • Use the diameter symbol(⌀) before giving the size. 

How To Size Hole Dimensions in Technical Drawings?

First of all, you need to understand the difference between holes and cylinders in technical drawings. You are sizing the external surface of the cylinders and the internal surface of the holes in technical drawings. 

When sizing the straight hole dimensions in technical drawings; 

  • Use diameter symbol(⌀) again just like in cylindrical dimensions, and show the size after that. 
  • Unlike the cylindrical shapes, you must give the dimension leader on the round view. The leader must be centered in the center of the hole. 

As you understand, technical drawing has so basic rules. If you obey these rules, you will create technical drawings under international standards. 


Dimensioning the cylindrical shapes and holes in technical drawings is like this. 

Do not forget to leave your comments and questions below about the dimensioning holes and cylinders in technical drawings. 

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