Motherboard screws

[Evan007]

Hello,

I'm building my first computer and have a question about what type of machine screws to use to install the motherboard in the case.  The case came with brass standoff nuts that are threaded but they didnt pack the screws with it.  I went out to buy machine screws that would fit but could only find steel screws.  My motherboard manual says not to have any metal components on the motherboard or in the case that could cause a short circuit.  Does that also apply to the screws?  I think it is ok to use but i want to make sure.  Otherwise you would have to use plastic screws...

Thanks,
Evan

[camerongray]

You can use metal screws yes.   You can probably get some screws designed for motherboards quite cheaply online.

[Salmon Trout]

Brass or steel screws are the usual type. The type is determined by the standoffs you are using. There are two main screw types, "6-32" (most common) and "M3" (less common). Practically every electronic/computer parts store will sell bags of 50 or 100 of these for small change prices. Or you can get them online. A store may allow you to take along a standoff and try which thread type 6-32 or M3 you need, although standoffs are very cheap too.



If you look at each screw hole on the motherboard you will probably see a ring or circle of trace metal designed to contact the metal screw for earthing/grounding purposes.

[Evan007]

Thanks, I figured it was OK.  I actually went down to the local hardware store in my parents town and they had the 6 32 screws.  I thought those little dots around the screw holes might be related to grounding.

[DaveLembke]

I thought those little dots around the screw holes might be related to grounding.

They are for grounding. The board has a ground plane that is joined to the chassis ground via the mounting screws. If you used plastic screws you could run into a floating ground issue. I'd advise using metal screws that have a cap/head that do not exceed the circled area of mounting. Some screws that may be perfect thread size and length may have an unusually larger cap/head to them which can make contact with component leads or traces near by and cause problems. as long as the screw top does not make contact with component legs and you dont see any traces running under them that the mask gound become damaged and short to ground, you should be all set.

In the motherboard mounting hole picture that Salmon provided you see a white circle around the mounting hole, as long as the screw top ( cap/head ) doesnt overhang out of this circled area then your good to go. *Also do not over tighten the screws as for you can crack the PCB material damaging the board.