Best way to Cut a hole in case for fan?

[GI_JONES]

As the title says, I'm looking for the best...or actually the easiest way to cut a hole in the top of a case for a 120mm fan? This is just a spare system I am messing around with. I may end up cutting out the side panel for a window I scavenged out of another old case too. I considered a router with carbide bits but decided that cutting steel at 28,000 rpms would probably be dangerous. Would a jig saw be the way to go? I have a decent Dewalt one, and also have a small drill press with various sanding and rotary file attachments I could use to clean up the hole after jig sawing it. Not sure how well that method would work for a window though.
Thanks for any ideas

 

[Outlander_04]

Whenever Ive tried to cut a hole in sheet metal with a jigsaw its be slow , painful and messy . The metal gets bent unless its really well supported and you can control the jigsaw perfectly .

I havent done this to a case but you could try using a grinder . A 4 inch model might be idea. Angle it slightly and try and cut down in to the case . Maybe also the heat would warp things

Either way, I love my grinder

 

[GI_JONES]

I have a Dremel Tool also, but trying to cut a circle with a cut-off wheel, free hand doesnt sound like it would turn out well. I do have a couple of basically scrap cases I can practice different methods on.

 

[Outlander_04]

the cut off wheel is round. Hold it so its spinning horizontally and tilt it slightly so one edge just touches and its going to produce a fairly round hole

 

[photonboy]

Just FYI, but my Antec case came with two 120mm fans built in and was on sale at the time for $45.

 

[Onus]

I'm not sure I've seen a hole-saw big enough for a 120mm fan; that would be the quickest way to do it, using a drill press from the underside. In the absence of such a large hole-saw, use a compass to clearly mark the hole. Drill or cut well inside it, use a Dremel with a grinding attachment to get close, and finally file by hand to go out to the mark.

 

[jasont78]

there are whatever size holes saws you want, i use up to 5 inch ones all the time at work and thats the size you want for a 120mm fan

 

[jasont78]

As the title says, I'm looking for the best...or actually the easiest way to cut a hole in the top of a case for a 120mm fan? This is just a spare system I am messing around with. I may end up cutting out the side panel for a window I scavenged out of another old case too. I considered a router with carbide bits but decided that cutting steel at 28,000 rpms would probably be dangerous. Would a jig saw be the way to go? I have a decent Dewalt one, and also have a small drill press with various sanding and rotary file attachments I could use to clean up the hole after jig sawing it. Not sure how well that method would work for a window though.
Thanks for any ideas

if you cant get the holesaw do what u have mentioned and to finish it up use a drum sander, proper ones are on like a rubber door stop with a bolt running thru it and like a washers on each side with a nut to tighten it all up the idea is you put a cylindrical (drum shaped) sand paper on the rubber drum and by tightening the washers on the rubber it pushes it outward holding the sanding drum tight. if you can get that and want to make some thing up get something round that u can glue sand paper on to the larger the diameter the better finish u will get and put a bolt thru the centre of it to hold it with what ever tool u use and spin it on a drill, die grinder, dremel what ever you can get ur hands on

 

[Onus]

Ok then! Do it from the underside for neatness. You may still want to use the file on the edges.

 

[GI_JONES]

Best answer selected by GI_JONES.