Modding an aluminum case

[BMORIN]

How do you get perfect 80mm & 92mm holes in an aluminum case?

[Random Nonsense]

buying a set of holesaws is the only way you can get DIY perfect circles, jigsaws never quite manage and you end up filing for hours!

[BMORIN]

How do I know what size bit for holesaw to work for 80 or 92mm?

[Staz]

3" hole saw for 80mm. It makes it a little small byt not much. 3 1/2" hole saw for 92mm, same as above.

3 1/2" is hard to find. It is a nonstandard size.

[Random Nonsense]

Must suck being in america where you cant find metric sizes no matter what, here we can get anything, both metric and imperial are common

[drow_elf]

i've managed pretty good holes with a jigsaw.. the trick is to make a lot of "triangles" (hard to describe, the idea is to make room for the blade to turn so that you dont end up with a bunch of straight cuts)

[The Spyder]

Originally posted by Staz
3" hole saw for 80mm. It makes it a little small byt not much. 3 1/2" hole saw for 92mm, same as above.

3 1/2" is hard to find. It is a nonstandard size.

Realy? Because Homedepot, harborfrieght, lowes has em here in oregon....

[Staz]

Originally posted by The Spyder


Realy? Because Homedepot, harborfrieght, lowes has em here in oregon....

Really. Home Depot and Lowes don't carry a 3 1/2" hole saw here. It goes from 2" to 2 1/2" to 3" straight to 4". I didn't check with Harbor Fright. Local truevalue had one but by the time you bought the mandrle and the blade it cost about $56

[cloasters]

Hole saw, shmole saw. Always these Americans throw money at a problem. Just draw a hole in ink on the inside surface of a case cover, using the inside "circle" of the fan as a template. Or use a compass.

CAUTION. I've only done this with STEEL cases and case covers! Aluminum may easily be too wussed to handle this dare I say, inner city method.

Then use a slow turning power drill with a 1/8" bit to drill closely spaced holes around the circumference of the circle. WARNING- aluminum binds drill bits with a passion.

It's best to practice this on an extra case cover first! One snag of the drill can dimple or bend a case cover, just like that. You need to learn how to hold the drill in relation to the circumference of holes. A center punch is needed--otherwise the drill bit will wander. Did I say center punch? I mean a nail or a screw. A small chisel is needed to break the "spider web" of metal that's left between the ~50, 80 or 100 holes around the circle. I mean small screwdriver, of course.

A half-round file is a necessity. The teeth around the circle are nasty.

[stigweed]

I've found that taking your time wiht a jigsaw and always cutting within the circle so you can go and neaten things off afterwards works best. If its not quite straight - a little blowhole rubber surround with a grill on top of it smooths the curve and looks the dog's b*110cks.

I tried using a holesaw I picked up at work once. Size was perfect but steel ground the teeth down in the 20 minutes it took to scratch the surface. Gave up, drilled a hole and jigsawed it in about 5 minutes. Was a good quality holesaw as well good job I got it for free. It'll only eat wood from now on

[Holst]

I use a good quality drill press and use whats known as a "tank cutter"

Basically a blade on an arm that goes into your drill (a bit like a giant compass.

Quite a dangerous way to do it, but you can ajust the hole from 40mm to over 120mm and its allways perfectly round.
You need a good solid drill press and clamps to do it or you just get loads of vibration and a crappy cut.

[Holst]

Oh, tank cutter only cost me £8, so its cheap.

[Random Nonsense]

Originally posted by Holst
Oh, tank cutter only cost me £8, so its cheap.

I think thats what I would call a fly cutter... brilliant things, but need a pillar drill to use them safely

[Staz]

Originally posted by Holst
I use a good quality drill press and use whats known as a "tank cutter"

Basically a blade on an arm that goes into your drill (a bit like a giant compass.

You mean one of these?

Looks sweet.