How to cut slits in aluminum?

[sneakthief]

I'm going to buy a cutoff disk and stick it in my circular saw and I have some smaller aluminum panels I can do a couple of tests with.

I bet I could cut all 16 slits and deburr the edges in about 2-3 hours.

Pics will be taken, of course!

[TheAncientOne]

An old engineer's trick is to make a 'start slot on each slit, by drilling 3 or 4 holes, then joining them with a file, then to take 3 or 4 hacksaw blades, align their teeth the same way, thread them through the slot created, and lock them into the saw, (I've always managed to get 2 or 3 on the pins in my hacksaw, some saws struggle with 4). You now have a custom width slit saw. Cut the slot, and repeat. Not that fast, but less error prone and relatively cheap. If you want to improve your accuracy, clamping the panel down with a piece of wood batten, or mild steel strip to one side of the slit will give you a cutting guide.

I once, in my earlier days, did a 24 channel mixing desk this way, making sub panels to hold cheap sliders until we could afford the P&G ones, which came with a bezel.

Another useful tool is called an "Abrafile" or tension file: a circular abrasive blade that fits into a hacksaw frame with two special clips. Not expensive, and can cut curves.

There are 'slotting tools' for alloy, but the hand type will struggle at front panel thickness's.

A 'RotoZip' type, or mini router cutter will work, though again, you'll need to work out a guide block, because they have a tendency to make curves, used freehand. A variable speed one would be best, because the standard high RPM's are only good for wood, plasterboard or some plastics. Try a cutting lubricant, like ROCOL 'Ultracut' to stop the cutters clogging.

Problem with nibblers is getting one thin enough.

Abrasive wheels and alloy are not a good mix; they tend to clog with the soft metal and jam, you can burst a disc that way, and get quite seriously injured.

A 'Dural' type alloy cuts way cleaner and better than pure aluminium, which has a somewhat 'cheese' like texture.

Just a few thoughts.

Mike

[diablojoy]

with the abrasive type disc's and aluminium
true not a good mix however you can vastly improve the cutting
by adding wax to the disc , even simple candle wax will do the trick
IMHO a router is still the best way to go though for diy .

[julian]

If you have a drill press with suitable bearings, you can hold the job in a, umm, i forgett the proper name - movable vice? One that has two axis... (and then load the drill with a milling cutter)

Before i started doing CNC work, however, i used to just print out a CAD file with a load of center marks on the line, punch them, drill them, and then, as people have suggested, file them.

The trouble with a lot of approaches (ie jigsaw etc) is that its so easy to damage the surface of the metal whilst you are working on it.

[daverj]

[julian]

I would imagine the savings with FPD would be minimal at best.

If you think about it, there would be a small ammount of machine time saved, but all the other costs (processing, metal, preparation, clamping, tool loading, cleaning, packing, posting, etc.) would still be fixed.

(i realise not all of these are itemised in the FPD quotes)

[sneakthief]

I found this 3U Schroff enclosure and a virgin front panel for 13 euro (!) including shipping on ebay.de and decided to finally go for it after thinking about this for a couple of years.

Now I'll admit, I like things a bit quick & dirty. Although perfection isn't my goal, I also want to have a modicum of respect with my modular even though I want to spend the least amount of money.

Went to the local hardware store and picked up a metal cutting disc for 1,65 euro. It would have been better if the diameter was smaller so I could get a cleaner cut, but this was the only thing that fit in my circular hand-saw. The weight of the saw and the guides made things quick and painless.



I spent about 2 hours last night setting everything up and cutting and maybe 30 minutes filing the burrs away.

Drilling the rest of the holes and deburring took me another 2 hours today.

I lay out everything in photoshop, print out the page and tape it to the panel.

I drilled holes at the end of each slit for the slider screws. This helped even out the ends of the slits:



Next item is spray-painting everything black to cover the little marks I make during drilling ...and also to match the rest of my modular

Observations: well, the lines aren't perfectly straight because the saw wiggled a little bit without a proper jig. It will barely be noticeable when painted black.

Also, the aluminum between the slits bent in about .5mm at some spots because of the pressure of the saw. This too won't be noticeable.



Holes - 116
Slits - 16
Total time for the entire front panel machining - 4 hours
Money spent - 14,65 euro
Feeling so far - very satisfied

[emdot_ambient]

Nowhere near as bad as I would have done it!

Of course I would have had to spend a lot more than that since I don't have a drill press or a saw like yours...but neither do I have the inclination to want to have to do all that by myself. I really dislike doing the mechanical parts of DIY. Designing and soldering I like. Drilling and all that? Not for me.