Types Of Fits

Clearance, Interference & Transition Fits

Fit types vary based on how tight the fit is and how the parts are assembled.

Clearance fit means the hole's internal dimension is always larger than the shaft's external dimension. This creates a space or "clearance" between the two parts, allowing for smooth movement like sliding or rotating.

Slide fit involves two parts, a shaft and a hole, with a small, controlled clearance. This allows the parts to slide smoothly without too much play or resistance. Common examples include linear bearings and guide rails.

Interference fit, also known as press fit or shrink fit, happens when the shaft is slightly larger than the hole. This creates a tight fit when assembled, as the parts are forced together, forming a strong, frictional bond.

When choosing among these three types of fits, consider a few key factors. First, think about the application requirements. Do the parts need to move or bear loads? Clearance fit provides "breathing room" for free sliding or rotation. Slide fit ensures smooth gliding without excessive play. Interference fit offers a strong, secure connection for parts that need to be fixed together.

Material choice is also important, as different materials expand and contract differently, affecting the fit. Finally, consider manufacturing tolerances to ensure accuracy during assembly. By weighing these factors, you can select the best fit type for your design.

These three categories can be further divided into ten subcategories. For more details, please click the link below to view the original text.