DIY - Over Bunk Fans

DIY - Over Bunk Fans

When it's very hot & humid at night it can be difficult to sleep.  Next morning you feel exhausted and grumpy.  Just moving the air around you is often enough to let you drift away provided the fan is not too loud.

We use 6” computer case fans (12v) mounted on home made swivel brackets over each bunk. Look for fans that are 18db or less as these are almost silent in operation.

They are very simple to make, here's how to do it:

You will need the following bits:

  • An Ultra Quiet Computer Case fan such as the 6" Alaska from Maplins
  • about 500mm of aluminium bar20mm by 2 or 3mm
  • an in-line switch
  • a length of 2-core 12v wire
  • 2-  5mm pan-head machine screws each about 25mm long
  • 1   -  20mm x 5mm pan-head wood screw and washer
  • Electric Drill with 3, 4 & 5mm drill bits and a countersink bit
  • 5mm Tap with Tap Holder
Look for a 6" case fan that is 18dbA or less.  The quieter the better

Look for a 6" case fan that is 18dbA or less.  The quieter the better

Mark the centre point on each side of the fan and drill a 3mm pivot hole.  Ease the edges of the hole with a countersink drill bit.

Mark the centre point on each side of the fan and drill a 3mm pivot hole.  Ease the edges of the hole with a countersink drill bit.

Cut and bend the aluminum bar to be a snug fit around the case fan.  You want no more than 3mm clearance at the sides so the fan can swivel freely.  Leave about 15mm above the fan so the fan wiring doesn't catch the swivel arm and trim the bar so that it extends a further 15mm beyond where the pivot hole sits in the case fan.  Drill a  5mm  hole in the centre of the top section .   Position the bracket carefully around the fan, mark and drill  4mm  holes opposite the pivot holes in the case fan sides.

Cut and bend the aluminum bar to be a snug fit around the case fan.  You want no more than 3mm clearance at the sides so the fan can swivel freely.  Leave about 15mm above the fan so the fan wiring doesn't catch the swivel arm and trim the bar so that it extends a further 15mm beyond where the pivot hole sits in the case fan.  Drill a 5mm hole in the centre of the top sectionPosition the bracket carefully around the fan, mark and drill 4mm holes opposite the pivot holes in the case fan sides.

Slide the fan into the swivel arm to check a good fit and mark the side holes.

Slide the fan into the swivel arm to check a good fit and mark the side holes.

Carefully Tap a 5mm thread into the 4mm drill hole.  The aluminium is soft so take your time to get a good clean thread.

Carefully Tap a 5mm thread into the 4mm drill hole.  The aluminium is soft so take your time to get a good clean thread.

File the end of the 2 small 5mm pan head machine screws into a point that will fit comfortably into the countersunk pivot hole drilled into the fan sides.  The screws need to be about 20mm long.

File the end of the 2 small 5mm pan head machine screws into a point that will fit comfortably into the countersunk pivot hole drilled into the fan sides.  The screws need to be about 20mm long.

Thread the machine screws into the bracket ends.  They can be adjusted in and out to allow the fan to tilt easily but stay in the position set.  Don't over- tighten or the thread will strip.  If it does you will have to use a lock nut or make a new bracket.

Thread the machine screws into the bracket ends.  They can be adjusted in and out to allow the fan to tilt easily but stay in the position set.  Don't over- tighten or the thread will strip.  If it does you will have to use a lock nut or make a new bracket.

Place a large washer between the bracket and the ceiling or wall too allow the bracket to swivel freely without marking its surroundings.

Place a large washer between the bracket and the ceiling or wall too allow the bracket to swivel freely without marking its surroundings.

The case fan usually has 3 wires and comes with a small connector to 4 wire adapter.  The Red is battery +ve the Black is -ve.  You can snip away the yellow and black pair as they are not needed for this purpose. 

The case fan usually has 3 wires and comes with a small connector to 4 wire adapter.  The Red is battery +ve the Black is -ve.  You can snip away the yellow and black pair as they are not needed for this purpose. 

Wire it up like this and you are good to go.  I usually try to pick up 12v from a local over-bed light.  The fan draws almost nothing in current so the lighting circuit is fine.

Wire it up like this and you are good to go.  I usually try to pick up 12v from a local over-bed light.  The fan draws almost nothing in current so the lighting circuit is fine.

 

 

 

 

 

 

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