The focus of this paper is to survey recent patents related to mechanical tolerances. First, a general overview of tolerances is provided, followed by issues related to research in mechanical tolerances. Various research aspects of mechanical tolerances that are introduced are tolerance specification, analysis, allocation, synthesis, transfer and evaluation. Patents related to mechanical tolerances, issued since the beginning of the millennium, are selected for the survey. A comparison of the claims in the patents is provided, followed by the discussion of future research issues in mechanical tolerancing.