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.

spring pin 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 a slotted, cylindrical pin that expands against the hole after insertion, creating a tight fit that prevents loosening. This property lets spring pins both withstand shear and absorb vibration, making them an indispensable “invisible guardian” in many systems. --- How to Determine the Right Spec？ When selecting a spring pin, the

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

Parallel Key In mechanical transmission and assembly, the parallel key is a small yet crucial component that determines whether parts operate securely. Installed between the shaft and hub (such as gears, pulleys, and couplings), it transmits torque and prevents relative sliding. If the size is chosen incorrectly or installed improperly, it can lead to loosened parts, reduced mechanical precision, or even shaft damage. --- How to Select Parallel Key Size Selection is mainly ba