I looked at some posts and videos about making mounting holes but it’s not clear to me what the best way is. In pcbnew I put the component MountingHole_3.2mm_M3. By default there is a narrow exclusion zone right around 3.2mm.
I am using metal posts and screws so I need quite a bit more non-conductive clearance around the hole (about 7mm diameter). Some people suggest to adjust the pad size as shown here
This will create a copper pad around the hole with a narrow area around the pad size that has no copper, i.e. the black area here:
I guess this is functional and I have seen plenty of PCBs that have copper around the mounting holes which never made much sense to me (maybe there is a reason).
As you can see, I have a copper field and some people suggested to increase the minimum distance between copper field and components/traces. However, in most cases I want to keep this distance small, i.e. much smaller than the ~2mm I am trying to create around the mounting hole.
I experimented with a few more parameters and think the “Net pad clearance” might do the trick. I set this to 1.9mm because I want 7mm diameter clearance. The hole has a radius of 1.6mm (M3, 3.2mm hole). 7mm diameter clearance = 3.5mm radius. 3.5mm - 1.6mm = 1.9mm.
This results in the following:
This looks pretty much what I was looking for, i.e. a 3.2mm hole for a M3 screw and 7mm diameter clearance without any copper. Will this work or did I miss something that might create a connection to the copper field or any components?