The followings would be the normal symbols for geometric tolerance shown from the drawings of iron and steel castings. We simply shortly introduce their definitions, and hope they could be helpful for buyers and suppliers to better understand the drawings.
Right straightness, indicating the tolerance for straightness to at least one edge or to one line.
Flat flatness, indicating the flatness to a single area. Higher level means the top needs to be really flat. Often this tolerance is actually for the harsh area of material castings.
Round ovality, showing how round for just one circular surface. If circular tolerance is high, then it means the ellipse and unusual circle won’t be allowable.