Heres the steps Mnpctech follows for installing an intake or exhaust fan in the floor of a computer chassis

Read more about the tools Mnpctech used in this guide, Recommended Tools For Case Modding

We first apply 3M Green (low tack) Painters tape before marking off the fan hole location. We’re using a 120mm steel fan guard as out template for the fan hole with a measuring square.

The fan guard allows you to mark the center of the fan hole.

Using hand punch to pin point center before using 1-1/2″ hole saw attachment to acommondate Greenlee Knockout shaft.

After cutting 1-1/2″ hole for Greenlee knockout shaft.

Greenlee Knockout Punch for 120mm fan holes

Tightening Knockout Punch with Socket Wrench

Removed portion of chassis (120mm hole)

Clean cut hole, no need to file edges

Using Roper Whitney Hand Punch to cut fan screw mounting holes

Another factory clean cut hole!

We’re now ready to install the 120mm cooling fan

You may need to raise your chassis with larger feet to improve airflow beneath it.

Depending how high you’ve raised your chassis, or if your Motherboard allows enough space inside, you can either mount the 120mm cooling fan inside or beneath the chassis. If you’re using the fan as an intake, (drawing cool air into chassis) you should attach a filter to the fan, otherwise your fan will draw in a lot of dust.

Utilizing 2, sets of Mnpctech machined Diamond Knurl Case feet to raise the chassis so we can install the 120mm cooling fan as an intake beneath the chassis.