Does somebody know the type designation or standard of the M3-screws used to fasten e.g. a mainboard in place? I’m talking about the screws in the picture, hex-head with cross recess and flange.
Reason for asking this: I want to put them into my BOM for my 3D-printer.
@Steve_M Yeah, I know it’s M3 
My search results in something like ISO7380-2 but it’s still not exactly what I’m searching for…
oh I thought you were just after the size and thread pitch. Any reason a regular M3 philips screw won’t do? In fact I’d much prefer M3 hex screws (or allen head screws depending on where you’re from) since they don’t require any downward force to tighten.
The more I think about this, @Steve_M , the more I tend to normal M3-cheesehead screws, too. I already use many of them with TORX in my printer and they would probably do fine with the board, too.
If it’s to hold a PCB down, I’d be weary of some of those screws pictured if your board has traces near the screw holes. Some of them have serrated bits that bite into the motherboard since they’re usually grounded at the screw points.
@Steve_M To mitigate that, it might be a good idea to place a fibre washer between PCB and screw. It’s good practice to prevent grinding of the PCB surface.
I just mount my board with nylon screws. Double sided boards can have plating through the holes, fibre washer won’t save you if the screw touches the inside of the hole and rubs.
My 3drag board actually uses little plastic inserts that go all the way through the holes. I thought that was a good idea.
Standoffs
@Chris_Lyons read again 
That style of screw is known as a “phillips drive hex washer head machine screw” in the US. (also known as a flange head) There isn’t a DIN, ISO or ASTM spec specific for that head type in either my distributor’s catalog (both Grattan and PFC) or in the edition of Machinery’s Handbook I have. If it’s an M3 the threads with be defined by ISO 724:1993 and DIN 13 dimensionally. (pretty much all metric threads)
@Rene_Jurack Any Computer store will have them at least they will have an idea of what you are talking about.
nice printing
@Ashok_Gupta What do you mean?