Working with downloaded or imported models can create a situation where multiple pairs of holes cannot be mated concentric although there is no problem fitting manufactured components. SOLIDWORKS 2018 misaligned concentric mates option can account for this small difference in hole distances.
When the option ‘Tools > Options > System Options > Assemblies > Allow creation of misaligned mates‘ is enabled:
A conflict in concentric mates allows using a misalignment option as shown in the screenshot below:
In the PropertyManager for the concentric mate, offset can be applied to the first or second set of holes, or equally split between two sets.
Maximum deviation can be set when the option ‘Use Document Property’ is disabled.
Misaligned mates are shown in a separate mates folder.