Blowhole guide

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Even with a decent case there are times when you get the urge to improve ventilation, or add a radiator. Must admit to having had both urges , so hope this guide will help

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Hole saw Sizes

Hole saw needs to be smaller than width of fan, these are about the optimum sizes for the corresponding fan size :-



Examples
Silverline Bi-Metal Hole saw 114mm
Silverline Hole saw Arbor 30 - 150mm with Pilot Drill, Hex Shank

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Other Tools

4x No8 2.5" wood screws any length > about 1.5” will do, I just had these. They fit well in the fan mounting holes & if tapped with a hammer give the exact centre point for the case fanhole position.

4~5mm / 3/16” drill bit for fan screwholes

Variable speed power drill .(about 3~4A power)

Half Round File*
Has a D Profile Flat side & arched.
Round File*
Fully round file.
*File prices vary greatly I got a kit of 3 from focus for about £3~4, so look around, or knick someone else’s

Centre Punch

Hammer

1st aid kit you need to take care, plastic goggles are a good idea

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Cover the area your working on with masking tape.

This provides 2 things:-
1) Helps reduce potential skidding of drill bits or hole saw.
2) Enables drawing and marking of any lines or holes.



Tips:
Always ensure that the metal being cut/drilled is supported on the underside to prevent the metal being bent / bulged from the pressure of the hole saw or drill bit.

Here i have a block of wood bolted through the fan holes, which will support the pressure of the hole saw which will be cut from the other side.

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If the hole is to be in the top of the case, i usually work with the case inverted on bench / block of wood. so work from the inside of the case & prepare it with masking tape.

I use No8 2.5" wood screws to help mark the position of the holes.


Best results I find is to drill a hole at a time as:-

Identify where you want to put the 1st hole.
1) Use the fan with the screws in as shown & lightly tap the head of the screw.
2) Remove fan, use the Centre punch and hammer, to create a start point for the drill bit over the mark created in 1)
3) Using a 4mm / 3/16” drill bit put the bit in small indent created in 2) have the speed setting to high & drill hole.
4) Place bolt or screw through new hole and fan & repeat from step 1).

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Place bolts or screws through the 4 screw holes you just made.

Use 2 elastic bands as shown to locate the centre.

Mark the centre and use the centre punch and hammer again to create the start point.

Drill the hole using the pilot bit that comes with your arbor.

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1) Mount Hole Saw on Arbor and attach to drill. It's worth using some lubricant on the cutting edge of the hole saw

2) Try to get the case on a level surface, this helps ensure an even cut.
This was my 1st hole, you can see the cut is uneven due to an uneven floor, leaves more filing and smoothing to do.


3) Set the drill speed to around 2/3 maximum power. Too slow and you get too much torque that risks burning out your drill, too fast and handling can get difficult, making things unsafe.

4) Ensure hole saw and arbor are straight by turning on drill, there will be a little lateral wobble, but not much. If you do feel it wobbles to much remount hole saw and arbor.

Place pilot bit in centre hole , gradually let the hole saw move onto case. There is no need for any downward pressure the main thing is to keep the case still. There case tries to rotate in the same direction a the hole saw, this movement needs to be stopped. I find it easier to have the case between my knees, a bit like sheering sheep

Keep your finger on the trigger and be ready to release trigger whenever you feel uncomfortable. The process can be done in several short runs should you wish it. re-lubricate if you want , but generally a single lube is enough.

Once the cut is done you can remove the supporting wooden block , and admire your handiwork.

This was my 1st hole which as you can see had 2 issues :-
1) Scratch , from saw slipping , I was using too low a speed.
2) Poor cut through , due to uneven floor.

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Whilst looking pretty bad initially, both these issues were easily remedied.

Use a round and half round files to remove any sharp or uneven edges.

With a black case a permanent black marker can be used to cover any scratches. I was very skeptical when told this, but very pleasantly surprised when it worked.

The hole to the front is the original scratched blow hole.
Did a better job with the second hole added for a radiator. If you can it shows that a practice run can be worthwhile if practical.

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By comparison drlling holes into the side panels are a breeze

SidePanel holes for twin 120 intake fans covering Memory & CPU

[death]

reall nice guide m8 great work