Hi Stefano,

Maybe someone else will have a better way to answer your question, but to me, it sounds like you're asking about the simplest way to cut holes to accommodate fasteners while allowing for standard clearances. If you already have a model of the fastener, then you could use it to cut the hole with a boolean diff but that hole would not have clearances which is why I offered the suggestion to create your own cutting object with the desired clearance.

> The post was also trying to indicate screws are pretty standard so even without a 3d model it
> would be interesting to understand how to pick a point and create the hole detail 1st, ideally in a click.

Given your solid bar, use the Cylinder command to create the appropriate sized cylinder, then use Construct Boolean Diff to subtract it from the bar. Or you could use Circle to create the curve, then Extrude it followed by the Boolean Diff.

--Larry