The most common method is to call them out to be masked but with no dimensions so we go with 1/4" or 5/16". Often, when I ask if a dimension is needed, they say to just ensure the bore is free. Next most common would be specific dimensional masking. I often get this from aerospace customers. The "newbies" to coating will often call out an exotic dimension that cannot be masked with a common sized, easily available tape-dot. Which substantially adds cost to have them custom cut. Functionally, if nothing metallic will be exposed, it doesn't matter how big it is. Lloyd Duso Diamond-MT (814) 535-3505 www.Diamond-mt.com On Thu, Jan 10, 2019 at 4:36 PM Jack Olson <[log in to unmask]> wrote: > Is it more common to conformal coat unplated mounting holes? > or designate a clearance diameter on the assembly drawing? >