Using a hole saw with aluminium

[AdamW]

I need to cut a hole in 2mm thick aluminium (A PC case). The aluminium is drilled with a lot of holes (it is a vent, but I need to make it less restrictive).

I have a set of wood holesaws. As I had a spare PC case lying around I tried them on that but as THAT case is steel, it barely scratched it. I wasn't really expecting it to cut it, but if it made more of an impact I would have tried it on the alu seeing as it is a softer metal.

So, what type of holesaw should I be looking to use on aluminium to make a hole around 10-12 cm in diameter?

 

[nstreet]

Get a decent electricians holesaw that is designed for the job of cutting metal. I assume you have a cheap job from the DIY shed's?

Why do you think the current vent is restrictive, what sort of mods are you carrying out?

 

[AdamW]

Ah, of course: they need to cut metal trays don't they.

Well, the reason is, the grille is quite restrictive.

That is a different model to my case, but the grille is of the same design. What you are looking for is the one in the centre of the picture with the plastic studs in the corners. It is more metal than air! You can feel (and hear) the turbulence around it when you have the fan running at a reasonable pelt. So, my plan was to take all the computer bits out of the case, mount a block of wood inside the case (held in place by screws in the fan-mounting holes), and drill from the outside. The wood block would only be there to avoid mangling the metal, and would be removed afterwards.

Yes, it is me with my obsessiveness on quiet computing again! It is the only fan in the whole computer. A fan at that location normally blows air OUT of the case, but this one sucks air INTO the case. It is then directed (via a baffle) onto the CPU heatsink. If I can make the vent less restrictive then I can have the fan running more slowly and therefore more quietly.

I have a Dremel, but that is dangerous enough when cutting straight lines, and I doubt it would be any good with circles.

 

[kevplumb]

bi metal hole saw

 

[AdamW]

Thanks for the suggestions guys. I've had a look at some bi-metal HSS hole saws now, they seem suitable. Pretty expensive to buy one in the size I need though (well, for cutting one hole anyway!), but my neighbour did once say that if I needed to borrow any tools to ask him (and he had quite a large holesaw in his hand at the time!)

 

[Sandy Beech]

Thanks for the suggestions guys. I've had a look at some bi-metal HSS hole saws now, they seem suitable. Pretty expensive to buy one in the size I need though (well, for cutting one hole anyway!), but my neighbour did once say that if I needed to borrow any tools to ask him (and he had quite a large holesaw in his hand at the time!)

Based, as you are, in the Holy City getting one the size you need should prove no problem at all

If instead you lived in Birminham you could get just what you need at a reasonable price from The Toolman of Yardley. I have no connection - don't even like the guy - but his prices are hard to beat!

 

[nstreet]

Adam W if you have a spare bay at the front of your pc, why not try putting a vent panel in instead of a blanking plate. This will improve the air flow By sucking air into the pc, you will actually warm it up, you are also creating positive pressure inside the case which makes it harder for the fan to get more air in. How does the hot air get out again?

 

[AdamW]

Here is a picture of a PC built with the exact same case as mine. Unfortunately I don't have a digital camera yet, but this illustrates it well.

As you can see, everything is arranged upside down in this design of case. PSU is bottom right of picture, hard-drives bottom left, motherboard mounted upside down. Now, the fan I am currently using is the one that is a couple of inches to the right of the CPU. I am using a large Zalman "flower" heatsink, and found that the location of the CPU fan meant that air really wasn't flowing very well. So, I got rid of the CPU fan and turned the case fan back to front so it now blows onto the heatsink via a ramp (tried a duct, but surprisingly ramp seems to work better!

Negative pressure was considered, and will be tried once I have cut a better hole, but I figured that pushing cool air from outside the case straight onto the CPU would be more efficient. There are plenty of places for air to escape (I can feel a breeze coming out of various cracks and holes), but I may try removing some blanking plates and see if that helps too. I know you are only trying to protect me from ruining my brand new expensive PC case!

My only "mod" so far is having to cut the PSU mounting plate, there wasn't room for my PSU heatsink to hang out the back (fanless one of those too!)

 

[ChrisR]

Worth a search for some hole-cutters which sound like Queue -max, actually spelled either Q-Max or Cu-Max. THough if you sharpen an HSS drill correctly for aluminium they would do a fair job.

 

[david and julie]

I would of thought a jig saw with a hacksaw blade would cut a hole that size. A hole saw and arbour that big will be quite dear for a single use.

I would cut a piece of plywood as big as possible and mark your hole on it. Then screw this to the job with small screws in the corners of the part you are keeping and also in the waste. This will stop the ally chattering about and also stop you slipping and damaging the casing.

Take your time and let the blade cool off occasionally because it will get hot.

I have just re read all your post and noticed you had already decided to use wood,must stop reading posts and watching telly at the same time.

Still think a jigsaw would do it though.

 

[chappers]

you will be much better off fitting another case fan and blowing the hot air out, cool air will come in through even the smallest of openings at the same rate

 

[AdamW]

Well, no-one round here has the necessary tool, especially the sheds! Builders' merchants offered to order one in but pro tools come at a pro-price, about £40 including the arbour

I may well try the jigsaw as I had already bought some fine blades for it, suitable for soft metals (I guess that includes aluminium). If it looks pants after an inch or so I will order a hole saw off the net. But I know Dave does stuff with metal (although usually with a lump hammer and blowtorch if I recall ) so I am sure the advice holds true.

Chappers, thanks for the suggestion. Problem is, the grille over the fan is so restrictive it means the fan has to be spinning really quick to get decent airflow. Quick fan = loud fan!

 

[petewood]

Havent got a screwfix catalogue handy but I'm sure you can get a single bi-metal holesaw with arbour for well under a tenner.

 

[breezer]

Havent got a screwfix catalogue handy

why bother, go online

 

[AdamW]

Yes, rather amazingly Screwfix don't stock them in the size I require, unusual for them! They do a 102mm, but I am informed that the ideal size of hole for a 120mm fan is 114-118mm.

I have found a few sites that do them for between £15 & £20 once you add the arbour, Bosch as well (presumably better quality than random Chinese-made stuff!)

Seeing as it is essentially a drill bit I might be pushing my luck, but I will try my local tool hire place as well. Seeing as I only want to use it once I would rather pay £5 than £20!