Question When to use long screws and when to use shot screws to mount case fans?

[anandtechreader]

Hi, I have seen both long and short screws coming with case fans made by different manufacturers. When do I use the long ones and when do I use the short ones?

 

[Mr Evil]

The short screws pass through the panel that the fan is mounted to, and screw into the frame of the fan itself. The long ones pass through the fan and screw into the panel that the fan is mounted to (or into a nut behind it).

So, if you want to insert a screw from one side of a panel into a fan on the other side, and the panel has unthreaded holes, use the short screws. This will almost always be what you want.

 

[aigomorla]

the long screws are used when mounting a fan though a radiator for a watercooling set.
I have no idea why they would give you those screws as the other side would need to be threaded, which i have almost never seen a case with threaded holes unless its for motherboard standoff's.

The short ones are direct screw, you put them through the fan holes and the teeth grip on the edges of the fan though the holes.

The short ones are the ones you will mostly use, the long ones will only be used when you have a threaded hole and you need to screw the fan direct.