How to shape aluminum?

smitty2k1

King of Cable Management
Original poster
Dec 3, 2016
967
492
I've got an aluminum case that has an opening in the back for various connectors. I need to enlarge one by 3mm (height) in order to fit a power connector. I tried using my Dremel with a grinding attachment but the grinding wheel just gets gunked up with aluminum and doesn't grind properly. Any suggestions on how to enlarge this in a reasonable manner?

 

theGryphon

Airflow Optimizer
Jun 15, 2015
299
237
I did something similar using a drill and a metal drilling bit. Instead of drilling, use the bit to grind on the metal but gently, in and out with short strokes. No need for a lubricant. If you push it too hard, the bit may break or get stuck in the metal. Sorry for sounding pornographic, lol.
 

smitty2k1

King of Cable Management
Original poster
Dec 3, 2016
967
492
Use cutting wheel instead of grinding tool?
I don't really think there is room for a cutting wheel.

I did something similar using a drill and a metal drilling bit. Instead of drilling, use the bit to grind on the metal but gently, in and out with short strokes. No need for a lubricant. If you push it too hard, the bit may break or get stuck in the metal. Sorry for sounding pornographic, lol.
Yeah I was thinking maybe just getting an oversized drill bit and seeing if that works.
 

blubblob

SFF Lingo Aficionado
Jul 26, 2016
104
127
If you have a drillpress to align and fix the workpiece in relation to the drill you could just drill a fine line of connected holes and file down the rest for a nice finish with a metal rasp.

Considering the softness of aluminium, that the case is probably only a few mm thick and you only want to remove 3mm it would probably be only 20 minutes of work just using the metal rasp, completely forgoing the drilling. The grinding bit of a dremel is just to fast.
 

smitty2k1

King of Cable Management
Original poster
Dec 3, 2016
967
492
If you have a drillpress to align and fix the workpiece in relation to the drill you could just drill a fine line of connected holes and file down the rest for a nice finish with a metal rasp.

Considering the softness of aluminium, that the case is probably only a few mm thick and you only want to remove 3mm it would probably be only 20 minutes of work just using the metal rasp, completely forgoing the drilling. The grinding bit of a dremel is just to fast.

Ah a metal file, why didn't I think of that?? Thanks!!!
 

SFF EOL

Cable-Tie Ninja
Dec 9, 2018
154
36
Dremel do a special drill bit, it isn’t particular to Dremel though, they just do dinky versions. The problem is you use it with a drill press. You move the drill bit laterally and it works a bit like a milling machine. However, you’d need that plate off the back or a much better drill press (to clear the back of the case)- the drill bits are widely available and obviously with a ‘grown-up’ drill press and drill you can do more with MOR POWA! Dremel is great but I find it underpowered above 1.5mm and the benefits of a Dremel are somewhat lost once you put it in a drill press.


The drills will break/blunt but it is a sort of cheats version of machining. Many years ago, I was into model engineering (model trains) and it was a common cheat for those of us who couldn’t access the ‘proper’ equipment.


Another one I have learned. Someone asked me to make motherboard trays out of 3mm guillotine cut aluminium recently- as you guys will know that is quite easy. I just ordered 200mm square sheets. However, they weren’t happy as they wanted a lot of cut outs and they wanted the trays smaller. I used a tile cutter to reduce them down and it works. By tile cutter I mean the flat bed electric thing with a grinding disk, they are sub £100 in the UK and I had one. The disk was about £3 for a decent one. You wouldn’t want to do it all day and obviously the grinding disk doesn’t last for ever with aluminium- but it works for straight cuts. Because the tile cutter is relatively small you can fit smaller disks- you do need to let the disk run up to speed on mine as the torque is very low.

Also it files it down really well as it is abrasive. The disks are 3mm thick, maybe 2.8mm. You can get thinner but I didn't.