Answer: Drafting conventions are the standard rules and guidelines for creating technical drawings. They help to communicate the design intent and specifications clearly and accurately. Drafting conventions cover aspects such as drawing orientation, layout, symbols, material indications, line types, dimensions, drawing scale, diagrams, notation, and cross-referencing.
According to the drafting conventions, the drawing you have sent has some mistakes. Here are some of them:
The rectangle should be drawn with a continuous thin line, not a dashed line. Dashed lines are used for hidden features or outlines of adjacent parts.
The dimensions should be aligned with the dimension lines, not placed above them. The dimension lines should have arrowheads at both ends and should not touch the object. The dimension text should be horizontal and readable from the bottom or right side of the drawing.
The units of measurement should be indicated with the dimensions, such as mm for millimetres or in for inches. The units should be consistent throughout the drawing.
The scale of the drawing should be stated in the title block or near the drawing. The scale should be written as a ratio, such as 1:10 or 1/4" = 1’. The scale should be appropriate for the size of the paper and the level of detail required.