Cutouts in heavy aluminum

[Rip Van Woofer]

Any metalworking gurus here?

I'm building some plate amps for eventual integration into some powered DIY speakers, and the plate chassis will be 1/8" thick aluminum.

My problem: cutting reasonably clean small (about 1" x 2") rectangular holes in the aluminum without access to something like a Bridgeport milling machine. I tried a Dremel with a tungsten carbide bit allegedly for metal, and after nearly an hour had a very ragged cutout and two useless bits (at $14 a pop - one broke and one dull) for my trouble. I have to cut eight such holes.

Stuff's too thick for a manual nibbling tool.

 

[WmAx]

Any metalworking gurus here?

I'm building some plate amps for eventual integration into some powered DIY speakers, and the plate chassis will be 1/8" thick aluminum.

My problem: cutting reasonably clean small (about 1" x 2") rectangular holes in the aluminum without access to something like a Bridgeport milling machine. I tried a Dremel with a tungsten carbide bit allegedly for metal, and after nearly an hour had a very ragged cutout and two useless bits (at $14 a pop - one broke and one dull) for my trouble. I have to cut eight such holes.

Stuff's too thick for a manual nibbling tool.

There is a local shop that specializes in cutting. For plate like this, they use a laser cutter. It's not expensive, from my memory. See if you have such a custom cutting shop available locally. Seems easier than using a Dremel(!).

-Chris

 

[soniceuphoria]

Drill a hole in the plate and use a jig saw with a metal blade and cut out your squares. This should work for you and cost a lot less than taking it to a machine shop and paying $100/hr. for labor. I hope those amps work out for you Rip. Happy Listening.
Greg

 

[philh]

Any metalworking gurus here?

I'm building some plate amps for eventual integration into some powered DIY speakers, and the plate chassis will be 1/8" thick aluminum.

My problem: cutting reasonably clean small (about 1" x 2") rectangular holes in the aluminum without access to something like a Bridgeport milling machine. I tried a Dremel with a tungsten carbide bit allegedly for metal, and after nearly an hour had a very ragged cutout and two useless bits (at $14 a pop - one broke and one dull) for my trouble. I have to cut eight such holes.

Stuff's too thick for a manual nibbling tool.

Carbide bits do not like aluminum. Tends to gum up the teeth. HSS bit may have worked, but for as soft as Al is, it can be tough product to work with.

I like the drill hole then saber saw routine, just use a fine blade, 1/8 plate is not very thick.

 

[Mudcat]

I'll Seconded that motion

As Soniceuphoria said use a jig saw or more precisely:


http://www.homedepot.com/prel80/HDUS/EN_US/diy_main/pg_diy.jsp?BV_SessionID=@@@@1710452972.1118333577@@@@&BV_EngineID=ccdhaddelgdjfmgcgelceffdfgidgll.0&CNTTYPE=PROD_META&CNTKEY=Super Categories/Tools & Hardware&MID=9876&pos=p07[url] dam that's a long url

 

[MacManNM]

Any metalworking gurus here?

I'm building some plate amps for eventual integration into some powered DIY speakers, and the plate chassis will be 1/8" thick aluminum.

My problem: cutting reasonably clean small (about 1" x 2") rectangular holes in the aluminum without access to something like a Bridgeport milling machine. I tried a Dremel with a tungsten carbide bit allegedly for metal, and after nearly an hour had a very ragged cutout and two useless bits (at $14 a pop - one broke and one dull) for my trouble. I have to cut eight such holes.

Stuff's too thick for a manual nibbling tool.

Draw on them what you want cut out, mail them to me and I'll use my millng machine and cut the stuff out.
This will be done for a favor to be named in the future. jk

 

[mtrycrafts]

This will be done for a favor to be named in the future. jk

Ah, an open ended, unspecified deal?
Something like the godfather made?

 

[MacManNM]

Ah, an open ended, unspecified deal?
Something like the godfather made?

I tried not to make it too obvious.

 

[Buckeyefan 1]

As Soniceuphoria said use a jig saw or more precisely:


http://www.homedepot.com/prel80/HDUS/EN_US/diy_main/pg_diy.jsp?BV_SessionID=@@@@1710452972.1118333577@@@@&BV_EngineID=ccdhaddelgdjfmgcgelceffdfgidgll.0&CNTTYPE=PROD_META&CNTKEY=Super Categories/Tools & Hardware&MID=9876&pos=p07[url] dam that's a long url[/QUOTE] How about renting a 35 amp plasma cutter?

 

[Tom Andry]

How about renting a 35 amp plasma cutter?

That just sounds like fun!

 

[yelo]

Use that Dremel with the cutoff blades....they break alot but the're REALLY cheap and will cut through 1/8" aluminum very easily (I just finished a project that required almost identical cutouts to yours...this worked GREAT for me)

 

[brian32672]

Use that Dremel with the cutoff blades....they break alot but the're REALLY cheap and will cut through 1/8" aluminum very easily (I just finished a project that required almost identical cutouts to yours...this worked GREAT for me)

Yeah, I used the cutoff blades for 1/8 steel. Damn it took a lot of patience and time. But it will work fine. You will still want to slightly file or use a drum sander in the dremel to slightly clean up edges. My use was not for a amp, but rather computer case modding. (Not a aluminum case) I have also seen this done with diamond plate, once again a lot of time and patience, also use the fiberglass reinforced blades over the thin composite blades.

 

[rasman]

Working with Aluminum

Working with aluminum is mostly a pain because of jamming. Too much heat, too little heat, not sharp enough all are part of the cutting of alu. You can cut or mill aluminum if you keep it lubed and cool. A-9 cooling agent, or even kerosene can be used to cool so cutting or milling can be accomplished.
Now for cutting squares, drill and jigsaw can work. Make sure the jigsaw blade is of proper teeth per inch and coating with a something to keep it from jamming. The old method is to rub chalk, or soapstone on the blade, that will reduce jamming with particles. This dry method stays away for wet lube which may cause problems with electrical power tools. Just rub chalk or soapstone on the blade, cut for awhile, repeat when neccessary.
Using a Drill press with a two way vise can work but may be a more complicated depending on plate.
There are other home methods.
If you were going to cut alot and I do mean alot. Have the plate water jet cut, fast smooth and is programmed with computer mapping. I would recommend it over CNC because of finish.
rasman

 

[AverageJoe]

How 'bout a Greenlee knockout punch? This one's for a 5/8" square, but they make larger ones.

http://cgi.ebay.com/GREENLEE-KNOCKOUT-PUNCH-625-15-9mm-square_W0QQitemZ270010208700QQihZ017QQcategoryZ73116QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

I've never tried it on aluminum, but I've used them on steel pedestals and electrical panels.

 

[majorloser]

Plasma cutters leave a jagged hole requiring cleaning. Jig saws will leave a hole you'll have to sand and finish. A knock-out will bend the edges of the hole.

The best cut will come from a water jet. Because it uses an abrasive in the water it sands the edges smooth. The finished product will be so nice you could even powder coat it with little to no prep work. There should be a shop in you area you can take it to for cutting. It will take them more time for them to program the pattern than the actual cutting.

BTW- I think I'd go for a heavier material, like 3/16" or 1/4". 1/8" alluminum becomes weak with large holes.

EDIT: Here's an example: http://www.waterjetservices.net/

 

[highfihoney]

hi rip,i dont think its the fault of the dremel or the cutting bit, most likely its the heat caused by cutting aluminum,you can buy several products like TAP MAJIC or COOL TOOL at industrial machine supply stores like MACHINE TOOL SUPPLY,if i remember right your in michigan & these chains of supply houses are all over the state,the one that comes to mind is on telegraph just south of I 96.

I used to own a bridge port & a metal lathe & that is where i bought all my gear at,if i remember right i believe that they also sell cutting bits that will fit into a standard router.

 

[Johnd]

Old school is soapstone or chalk...just reapply every couple of minutes to keep the bit cool.

 

[Johnd]

You can also purchase a spiral carbide router bit and route the holes (if you have a powerful enough router). With a pattern jig, the finish should be good enough where you will not require additional finishing.

 

[j_garcia]

Why not just DRILL holes instead of rectangular cuts? Could always drill two holes about 2" apart and then use the dremmel to connect them.