What is the term for the necessary clearance between meshing gear teeth?

Backlash refers to the necessary clearance or distance between meshing gear teeth that allows for slight movement without binding. This clearance is crucial in gear systems to accommodate thermal expansion, ensure smooth operation, and compensate for manufacturing tolerances.

When gears rotate, any type of friction or misalignment can cause the gears to become less effective if they are too tight, leading to increased wear and potential failure. Backlash allows for free movement between the teeth, facilitating better operation and longevity of the gears.

The other terms listed have different meanings in mechanical contexts: gap generally refers to any space between two entities, play often indicates excessive movement in a mechanism, and lashback is not commonly used in gear terminology. This distinction emphasizes the importance of understanding specific mechanical terms to effectively communicate and troubleshoot engineering concepts.