I need a mounting hole for a #4 screw. I’m using Eagle.
I see a library “holes” with MOUNT-HOLES, with various size holes in mm, but what size should I use for a #4 screw?
With a little surfing it looks like a #4-40 screw and a 3.2 mm hole size would work. (7 mm keep out size).
So, I experimented with MOUNT-HOLE3.2, but I’m not sure that’s what I want.
First, the tdocu and bdocu layers have shapes that look like they are indicating plated through holes. I don’t need a plated through hole, just a mounting hole.
When I run DRC (using Sparkfun DRC rules) I get a “stop mask” error.
When I move the hole over traces, no additional errors are generated. I would have expected additional clearance, etc errors to have been generated.
Finally, the keepout area seems huge. The web source showed 7 mm for a 3.2 hole while MOUNT-HOLE3.2 has 8. It also shows plated through holes for a #4-40 screw with a 3.2 mm hole, a 5/6/7 mm “pad size” for stand-off/lock washer/flat washer.
So, can I use MOUNT-HOLE3.2 and just ignore the stop-mask error? Should I use top and bottom metal for a plated through hole? Is there something else I should use instead.
I plan to use BatchPcb.
Thanks,
Dave Thomas