Answer
Installation of multi-turn springs into deep blind bores requires precise alignment to prevent 'shingling' or overlapping of turns, which can lead to uneven load distribution. The primary challenge is the 'spring back' or radial expansion that makes insertion difficult. Using a tapered mandrel or assembly sleeve is critical. The sleeve's OD should be slightly smaller than the bore ID, allowing the spring to be compressed radially as it is pushed into position. In automated automotive assembly lines, load-cell monitoring is used to detect 'snags' during insertion; a sudden spike in force indicates the spring has caught on a groove or transition edge, which would result in a damaged spring and a non-compliant preload in the transmission clutch pack.
