What Is a Transition Fit?

A transition fit prevents parts in a manufacturing product assembly from excessive overlap, allowing for either clearance or interference of the parts being assembled. The engineer adjusts the shaft of parts so they fit together as tightly as possible, using a specific type of transition fit.

A transition fit allows for maximum accuracy in how parts fit together. Engineers use either hole or shaft basis systems when determining what type of transition fit to use. The clearance and interference for each part are different depending on the type of system used in the manufacturing process, so engineers analyze the parts to decide which transition fit to use to ensure precision of the final product.