On engineering drawings, we often see numbers like “±0.1” or “±0.05” written beside dimensions.These represent tolerance — the allowable deviation in size.But when a drawing contains hundreds or even thousands of dimensions, specifying every single tolerance individually becomes time-consuming and prone to error or omission. To help designers, manufacturers, and inspectors interpret allowable deviations consistently, the ISO 2768 international tolerance standard was created.

In many machines and structures, a spring pin is a fastener that relies on its own elasticity to fasten and locate parts.It is typically...

In many machines and structures, the cotter pin is a simple-looking part that provides crucial safety. Commonly used with nuts,...

In mechanical transmission and assembly, the parallel key  is a small yet crucial component that determines whether parts operate...