REQ: specification of fan size

[CrackerJack]

Does anyone know what the actual specification is of the physical
dimensions of fans to be found in a PC?

There are fans whose nominal size is 60mm, 80mm, 92mm and 120mm.

This size seems to be the outer dimension of the physcial unit.
The mounting holes are a bit less apart from each other. Does
anyone have the correct figures (with any tolerances) for these
fans?

By the way, are these dimensions a metric equivalent to dimension
which were originally specified in inches?

 

[kony]

Does anyone know what the actual specification is of the physical
dimensions of fans to be found in a PC?

There are fans whose nominal size is 60mm, 80mm, 92mm and 120mm.

This size seems to be the outer dimension of the physcial unit.
The mounting holes are a bit less apart from each other. Does
anyone have the correct figures (with any tolerances) for these
fans?

By the way, are these dimensions a metric equivalent to dimension
which were originally specified in inches?

A PC may have any of those sizes, even all of them in the same system.
Some sizes are more common than others for specific uses though, you'd
need to consider the specific application. If you're only considering the
"most" common case fan, that's 80x25mm, but today many cases can or do use
92-120mm fans.

The size is the outer dimension, width, not a dimension of the mounting
holes, which are also standardized based on the width of the fan, but
nobody specs by the mounting holes unless those holes are abnormal. In
other words if you held up any two randomly selected fans the mounting
holes should be an exact match. The tolernace isn't all that significant
to consider, if you had a fan with holes that were out of spec enough to
be problematic the fan is almost certainly such low-quality junk that it's
not worth using at all, today's manufacturing is plenty precise that this
is not an issue. If for some reason you need the exact hole measurements
you can visit the website of any of the major fan manufacturer's and
consult the spec sheet(s).

The dimensions aren't a metric equivalent, rather the opposite, someone
converts the metric to english, making it slightly more difficult to
reconvert for anyone used to sizing fans. That is, the vast majority are
made in the orient, not US or England, as are most cases and soon... darn
near everything.

 

[Bagpuss]

Does anyone know what the actual specification is of the physical
dimensions of fans to be found in a PC?

There are fans whose nominal size is 60mm, 80mm, 92mm and 120mm.

This size seems to be the outer dimension of the physcial unit.
The mounting holes are a bit less apart from each other. Does
anyone have the correct figures (with any tolerances) for these
fans?

By the way, are these dimensions a metric equivalent to dimension
which were originally specified in inches?

Is it to take a strobescope mounting too?



Seriously though measure from hole to hole for the mount points. Of
course it depends on which fan you are replacing. Rear case fans are
often 80mm.

 

[Piotr Makley]

Is it to take a strobescope mounting too?

Ha ha!

Seriously though measure from hole to hole for the mount
points. Of course it depends on which fan you are replacing.
Rear case fans are often 80mm.

If I measure from hole to hole then I get rather less than the
nominal fan size.

I sometimes need to buy fans to unusual heatsinks and when I work
out possible anchor points on the heatsink then I need to know the
correct distance between the holes of a fan I might fit.

 

[Bagpuss]

Ha ha!


If I measure from hole to hole then I get rather less than the
nominal fan size.

I know it may be teaching you to suck eggs, but am I right to assume
you are measuring center to center of the holes diagnoally across the
fan?

I sometimes need to buy fans to unusual heatsinks and when I work
out possible anchor points on the heatsink then I need to know the
correct distance between the holes of a fan I might fit.

Its worth having a look at somewhere like Maplins (if one is near by)
they do coolmaster fans. At the minimum you can get them out of the
boxes and measure across the screw mount points.

 

[ric]

Does anyone know what the actual specification is of the physical
dimensions of fans to be found in a PC?

There are fans whose nominal size is 60mm, 80mm, 92mm and 120mm.

This size seems to be the outer dimension of the physcial unit.
The mounting holes are a bit less apart from each other. Does
anyone have the correct figures (with any tolerances) for these
fans?

By the way, are these dimensions a metric equivalent to dimension
which were originally specified in inches?

http://www.nidec.com/fanpdfs/c2003_2425.pdf
http://www.nidec.com/fanpdfs/c2003_3132.pdf
http://www.nidec.com/fanpdfs/c2003_3536.pdf
http://www.nidec.com/fanpdfs/c2003_4243.pdf