Can someone help me ?

JPB

Diamond Member
Jul 4, 2005
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89
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Ok, I am making a custom case. And running into a few problems along the way. Now...I usually use 80mm fans. The fans I have here are supposed to be 80mm...but they are measuring differently. As if it is a 96mm. Now, can someone tell me how big to cut the hole for a 80mm ? And a hole for a 120mm ? Or can someone direct me to a site that has actual fan size or something of the sort ? Also, when measuring a fan, do you measure the inside of the casing ? The outside ? Or the blade itself ? Thank in advance




Edit : The fans ill be using is 3 5/8 on outside casing.

Inside the casing is 3 1/2

The holes are 3 2/8 from the left to right

John
 

Zepper

Elite Member
May 1, 2001
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The size of a fan is measured across the fan from one side of the frame to the other. FYI: They aren't metric fans - the metric number used like 80, 92, 120 (even 120 is an simplification for 119) are approximations. 3-1/8"~80, 3-5/8~92, 4-3/4~119 - the true fan measurements are english. Fan makers like NMB and Sanyo Denki provide mounting diagrams on their sites that show cutout diameters, etc.

So you have a "92mm" fan there. A cutout hole of approx 3-1/2" is good. Optimum would be a "squared circle" of 4" at the corners flatted to 3-1/2" on the sides. Or you could just cut a 4" hole and flatten the sides with tape on both sides of the metal.

.bh.
 

SparkyJJO

Lifer
May 16, 2002
13,357
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I believe when I measured an 80mm fan it was 80mm from center of hole to center of hole.
 

Zepper

Elite Member
May 1, 2001
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80mm fan is 4" (102mm) on center across the diameter 2-13/16 (~72mm) on center on the sides.

.bh.
 

Baked

Lifer
Dec 28, 2004
36,052
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The size of the hole you want to cut for 120mm fan is exactly the same as a CD. Do you have a drawing for the case w/ measurements? I'd go w/ 120mm fan(s) for the best cooling/noise ratio.
 

JPB

Diamond Member
Jul 4, 2005
4,064
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Thanks for the replies, they were very helpful, and come to find out, I did have 92mm fans...and not the 80's. I managed to cut the two holes perfectly. Each is 3 1/2 in