Square holes in aluminium... - Page 4

kruesi · 21st November 2009, 11:02 PM

Laser? EDM? CNC mill?

I usually mark it out, drill near the corners, and file, file, file. Nice job when I'm done, but there's GOT to be a better way. Takes forever and calls for a lot of patience. Out of all the things that are done by drilling/filing, the IEC 320 mains connector thing turns out to be the most difficult for some reason.

For larger rectangular holes, I drill near the corners and use a sabre saw with the finest blade obtainable, going very slowly, giving the edges a wide berth and taking care not to mar the finish (if BOTH sides have to be finished, this is a BAD IDEA!). In any case, this requires great care to avoid marring the surface with the saw's sole plate. Beats anything else I've tried for larger holes, (6-8" square or larger)

For smaller square holes (1/2"), I just drill the largest hole I can and file the edges square.

I'll admit to sometimes drilling a series of close-spaced holes (3/16 or 1/4), using dikes or a fire-ax or something to break the "web" between holes, then file, file, file. Good for odd-shaped holes of medium size, say 2-3" -or narrow slots. Have bandages handy.

Nibbling tools- I have to really consider if there might be a better alternative- and there usually is. They tend to mar the surface about 1/8" on either side of the slot they cut. Still need to file or otherwise finish. And for VERY large holes, my hands give out before the slot is cut. I generally agree- these instruments of torture offer only false hope, and should be banned.

A set of high-quality, perfectly clean and SHARP files is invaluable.

cddeluca · 9th January 2010, 09:47 PM

Buy an IEC extension cable: the male end accepts the female end of a regular IEC cable. Cut the end and connect it to the amp via a round hole and grommet. I'm not sure what makes an IEC connection so desirable - all my pro amps have little pig tail sort of cords on them, like a toaster. I don't se what's wrong with that approach for DIY too.

Fuling · 9th January 2010, 10:05 PM

From now on: EDM. My brother owns two Agiecut 100 wire EDMs. This technology is absolutely "the ****" when it comes to cutting non-circular holes in sheet metal...or in 10" thick blocks of hardened steel for that matter.

drspiff · 21st February 2010, 07:52 PM

Here is something that will make the filing easier. Put pieces of wood on both sides of the panel and clamp them in place with a couple of C clamps. Make sure the wood edges are lined up on your target line. Then file away.

Putting these pieces on either side of the panel makes the panel stiffer and makes the filing much faster. They also serve as guides to keep you filing flat and to tell you when to quit.

Dr. Spiff

tinitus · 21st February 2010, 08:27 PM

I dont know if its been mentioned
But files fore alu are made with a very special "cut"
They really are way more effective than ordinary ones
Especially if a lot of material is to be removed, or fore massive alu
Fore the last finer work, ordinary files are ok

Fore thin alu sheet I have also used a slim(5-10mm) and very sharp carpenters chissel, and a hammer

and its important to remember hardwood as backing, or it will bend

What I find the hardest is to avoid scratching the surface

9th January 2010, 09:47 PM	#32
cddeluca diyAudio Member Join Date: May 2009	Practical but not pretty Buy an IEC extension cable: the male end accepts the female end of a regular IEC cable. Cut the end and connect it to the amp via a round hole and grommet. I'm not sure what makes an IEC connection so desirable - all my pro amps have little pig tail sort of cords on them, like a toaster. I don't se what's wrong with that approach for DIY too.

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21st November 2009, 11:02 PM	#31
kruesi diyAudio Member Join Date: Oct 2009 Location: Chicago - Gritty, Grey and Windy	Laser? EDM? CNC mill? I usually mark it out, drill near the corners, and file, file, file. Nice job when I'm done, but there's GOT to be a better way. Takes forever and calls for a lot of patience. Out of all the things that are done by drilling/filing, the IEC 320 mains connector thing turns out to be the most difficult for some reason. For larger rectangular holes, I drill near the corners and use a sabre saw with the finest blade obtainable, going very slowly, giving the edges a wide berth and taking care not to mar the finish (if BOTH sides have to be finished, this is a BAD IDEA!). In any case, this requires great care to avoid marring the surface with the saw's sole plate. Beats anything else I've tried for larger holes, (6-8" square or larger) For smaller square holes (1/2"), I just drill the largest hole I can and file the edges square. I'll admit to sometimes drilling a series of close-spaced holes (3/16 or 1/4), using dikes or a fire-ax or something to break the "web" between holes, then file, file, file. Good for odd-shaped holes of medium size, say 2-3" -or narrow slots. Have bandages handy. Nibbling tools- I have to really consider if there might be a better alternative- and there usually is. They tend to mar the surface about 1/8" on either side of the slot they cut. Still need to file or otherwise finish. And for VERY large holes, my hands give out before the slot is cut. I generally agree- these instruments of torture offer only false hope, and should be banned. A set of high-quality, perfectly clean and SHARP files is invaluable.

9th January 2010, 10:05 PM	#33
Fuling diyAudio Member Join Date: Aug 2001 Location: Sweden (Mora)	From now on: EDM. My brother owns two Agiecut 100 wire EDMs. This technology is absolutely "the ****" when it comes to cutting non-circular holes in sheet metal...or in 10" thick blocks of hardened steel for that matter.

21st February 2010, 07:52 PM	#34
drspiff diyAudio Member Join Date: Jun 2006	Here is something that will make the filing easier. Put pieces of wood on both sides of the panel and clamp them in place with a couple of C clamps. Make sure the wood edges are lined up on your target line. Then file away. Putting these pieces on either side of the panel makes the panel stiffer and makes the filing much faster. They also serve as guides to keep you filing flat and to tell you when to quit. Dr. Spiff

21st February 2010, 08:27 PM	#35
tinitus diyAudio Moderator Join Date: Nov 2005	I dont know if its been mentioned But files fore alu are made with a very special "cut" They really are way more effective than ordinary ones Especially if a lot of material is to be removed, or fore massive alu Fore the last finer work, ordinary files are ok Fore thin alu sheet I have also used a slim(5-10mm) and very sharp carpenters chissel, and a hammer and its important to remember hardwood as backing, or it will bend What I find the hardest is to avoid scratching the surface

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