NPTH Mounting Holes ... AAAaarrgh! Or, how to get them right the first time

[Rene_Poschl]

Well to be honest it is quite a long post and i didn’t read it the first time round.

Now a long answer to your long post:

@Sprig

3. Notice that in the “Move and Place” section, the “Lock Pads” option is selected. Change that selection to “Free”; then click “OK”.

I was confused by that. Is it correct that you do that because you lock the component and don’t want to get a warning everytime you move it? The problem here is that if you only move the pad, your fab and courtyard layer markings do not move with them. (I have placed components to close to mounting holes before. I would strongly advice you mark the needed space on courtyard and fab layers and check if you violate them.)

@Sprig

5)In the “Pad Type” drop down menu, select “NPTH, Mechanical”.

There are plenty of mounting holes with none plated through holes in the library you mentioned.
Example: MountingHole_3.2mm_M3 (or just look in the preview. The footprints without a copper ring are the npth type mounting holes.)

I am also convinced that it might be a good idea to create a custom footprint if none of the footprints in the library fulfill your requirements. (Why? because you will need mounting holes on all of your pcbs. And i’m sure that a lot of them will be mounted in the same manner.)

As said above i would also show the outline of the screw or whatever you use to mount your board on the fab and crtyd layers. (You will thank me sometime in the future for this advice.)
Don’t forget that you will need space for your tools. (The fab layer has the outline of the screw head the crtyd layer the outline of the tool plus a bit extra.)

@Sprig

9. Notice that in the “Move and Place” section, the “Free” option is selected. Change that selection to “Lock footprint”; then click “OK”.

Very good idea if you don’t have the mounting holes in the schematic. Also very usefull for stuff like logos. They also vanish if you are not careful when importing the netlist. (or when using the new tool update pcb from schematic that is available in nightly)
But as said above this creates “problems” if you want to move the part. I would suggest you place the mounting holes where you need them and after that you do this.

A hint from my side: If you place the mounting holes use a grid that is as large as possible. This way you get nice measurements for the mounting hole distances. I normally use 0.5 or even 1mm grid for placing mounting holes and for the board outline. (The mechanical engineer that designs your housing will thank you for that.)

If you have external constrains on mount hole placement this thread has a quite good solution by @Joan_Sparky:

Import dxf of holes for precise mounting hole placement

I do the same. The dxf import has got very tiny marker holes in it (0.4mm) and the footprint for the NPTHs has got a cross hair. The hole from the dxf file that’s on the edge.cuts layer will ‘vanish’ in the drill hole definition that way, but I can leave it there for reference (surely could go for 0.1mm or less even). Considering the tolerances of the fab house for drilling the placement at 0.01mm grid is better by a factor of 10 or more. [image]