Various laboratory methods for measuring chip resistance were compared and found to rate different finishes in different orders.
A field survey showed that a gravelometer using gravel rather than other media correlated well with actual service results.
The necessity of preparing chip resistance test panels which very closely duplicate the actual finish obtained on cars was shown.
The nature of chipping has been studied and improved rating systems developed.
Detailed drawings, test procedures, and rating systems for the SAE gravelometer have been proposed for publication.