Feiltolerant

Feiltolerant is a term used in engineering and manufacturing to describe a design, component, or process that can accommodate material removal by filing during finishing without compromising function, fit, or safety. The concept emphasizes forgiving tolerances and intentional allowances that allow manual finishing to bring parts to their final dimensions or clearances.

Etymology and usage. The word combines the German feile (to file) with tolerant, reflecting its origins in discussions of finishing practices. It is not a formal standard term and remains relatively uncommon in official specifications, but it appears in some technical writings and industry discussions as a way to describe parts that can be adjusted by hand during post-processing.

Applications and design guidance. Feiltolerance can be relevant for prototyping, repair work, or low-volume production where precise machining is impractical. Design guidance typically includes providing modest finishing allowances, selecting materials that respond predictably to filing, and ensuring geometric features allow controlled material removal without creating functional or safety issues. Examples include brackets or housings designed with extra material for hand finishing to achieve a precise fit, or connectors that require small adjustments to achieve proper alignment.

Limitations and considerations. Relying on feiltolerance can increase variability if not managed, and excessive filing can weaken parts or alter performance. It is less appropriate for high-precision, high-stress, or safety-critical components where strict, verifiable tolerances are mandatory and post-processing must be controlled by machine processes.

See also. Tolerances, post-processing, hand finishing, design for manufacturability.