Best way to cut holes in aluminum chassis?

Russtafarian · « **on:** 25 May 2006, 03:58 am »

I just got a nice aluminum chassis for my UCD amp project. What's the best way to cut 1" holes in the back panel for mounting XLR and Speak-on jacks? Is there a certain kind of hole saw for this?

My next challenge is to cut a rectangular opening for the IEC power inlet. Any ideas on how to do that?

Thanks,

Russ

Gordy · « **Reply #1 on:** 25 May 2006, 04:06 am »

Hi Russ,

For the XLR and Neutrics use something like this... http://cgi.ebay.com/3-Pc-HSS-Titanium-Step-Drill-Bit-Tool-Set-Auto-Mechanic_W0QQitemZ7622170678QQcategoryZ67240QQssPageNameZWDVWQQrdZ1QQcmdZViewItem They're available at Lowes etc. and do a beautiful job. For the IEC it'll depend on how thick the Al. is... ?

Russtafarian · « **Reply #2 on:** 25 May 2006, 04:21 am »

Thanks Gordy! I can certainly pick up one of those bits.

Any ideas on the IEC would be greatly appreciated. The back panel aluminum is .09" thick.

Gordy · « **Reply #3 on:** 25 May 2006, 04:39 am »

If you cover the surface with masking tape you can sketch out your rectangular hole and then drill small holes in each corner... then use a key hole saw to cut from hole to hole... clean it up with a file afterwards! Well, I always have to anyway

It's four sided and not six sided?

JoshK · « **Reply #4 on:** 25 May 2006, 01:53 pm »

Here is another solution that I prefer to the step drill. The step drill works fine, but these are a little faster and easier to set up. If you are just looking for neutrix type hole punching you only need one, maybe two of these, which makes them inexpensive. I bought one of each.

25mm drill bit is what you need, iirc

I abandoned IEC, preferring to use powercon connectors instead for a variety of reasons, which makes punching holes easier too. Blue Circle also uses them now, so even some commercial acts are doing it.

Gordy · « **Reply #5 on:** 25 May 2006, 02:22 pm »

Those do look nice Josh and you can't accidently go to the next larger size hole, not that I've ever done something that duum.

The Neutric Powercons are excellent, I used them on my amps and the solid locking connections are much more secure than IEC's which seem to have very wide tolerances and very non supportive of heavier cords.

Russtafarian · « **Reply #6 on:** 25 May 2006, 08:23 pm »

Thanks for the help.

bluesky · « **Reply #7 on:** 11 Jun 2006, 11:47 pm »

Dear Russtafarian

The following are my two cents worth after making a few chassis:

First off ALWAYS measure twice or three times and then come back later and measure again!

get an automatic centre punch to mark drill holes, this stops the drill bit from wandering at the start,

get some cutting lubricant, any hardware shop should have some, it really helps the drilling process and provides cleaner cuts.

an automatic centre punch for marking holes,

a nibbling tool is great for making IEC holes etc,

a deburring tool to get the burrs off after drilling,

lastly, Morgan Jones is emphatic that any holes above 9mm should be made with chassis punches, however I can't afford these so what I do is to cut holes a couple of millmetres smaller and enlarge then with a file and sanpaper which is part of finishing anyway.

A great source for drill bits is Ken from VT4C, Ken has a good range of affordable bits plus a whole host of other delectable audio stuff. I have found Ken (Chung) to be a gentleman of integrity and recommend him wholeheartedly. Here is the link:

http://www.vt4c.com/shop/program/main.php?group_id=8

Best regards

Bluesky

JoshK · « **Reply #8 on:** 11 Jun 2006, 11:58 pm »

bluesky, those are the ones I linked to, they are very nice and affordable. I like them alot. I have dealt with Ken a number of times and even though it is an int'l transaction, it is a pretty easy one. The only pain is you have to add up the total weight for self estimating the shipping.

He sells good stuff at affordable prices.

Doublej · « **Reply #9 on:** 12 Jun 2006, 01:34 am »

I am not an expert here but I think the "best" way is a computer guided plasma cutting tool. No mistakes with this puppy.

If you live near the OCC perhaps you can convince them to give you a few cuts and cameo in exchange for showing off your kick ass stereo.

Berndt · « **Reply #10 on:** 12 Jun 2006, 03:56 am »

If you are trying to freestyle the hole with a hand drill not a drill press a step drill will be easiest. I use sharpy for a easy blueing and lay out with a ruler and scribe, or calipers if you have them.
I use wd40 on Al for coolant/lubricant as it is clean and available.
I get the most consistent deburing results with a half round jewlers file if I am looking for the best finish, this is more evident with a black anodized case albiet you can doll up scratchs on black anodizing with aforementioned sharpy.

MauiMods · « **Reply #11 on:** 2 Aug 2006, 05:55 am »

Mouser sells a knockout Die (knockout , I think).
You drill a small hole where a bolt will got threw with the die on each side of the metal you want to punch a hole threw. It gives a OEM style look. I wish they had on for IEC's though... well here is a link to the tool... only draw back, it is expensive..
if your going to use it for one hole... the brand is Greenlee if the link goes bad.

http://www.mouser.com/catalog/627/1753.pdf

JohnR · « **Reply #12 on:** 2 Aug 2006, 01:48 pm »

Check EBay for Greenlee punches before forking out for new ones...!

MauiMods · « **Reply #13 on:** 2 Aug 2006, 02:03 pm »

John, Do you know where I can get IEC punch like Greenlee operates?

Quote from: JohnR on 2 Aug 2006, 01:48 pm

Check EBay for Greenlee punches before forking out for new ones...!

JohnR · « **Reply #14 on:** 2 Aug 2006, 03:12 pm »

Hm, don't know about that. I use a square punch, a file, and "enthusiasm"

BTW I think the OP was asking about a 1" punch, here's one

Without looking into it I'm pretty sure that the "radio" or "chassis" punch is what's requried, the "knockout" punch is something different

Vinyl-Addict · « **Reply #15 on:** 16 Aug 2006, 11:27 pm »

Here's a tip if you ever drill a chassis or thin sheet metal in general. Back up the chassis or sheet metal piece with, at the very least a flat piece of wood. Clamp, iff possible the workpiece to the backing plate. Rigid setup is critical if you want a round hole. Don't drill a pilot hole. If you do, expect an oblong hole.

A drill point has an included angle of 118 or 135 degrees. If you don't back up the workpiece, the drill point will break through the thin chassis and have no contact with anything to keep it going straight so you end up with an out of round hole. If you back up the workpiece, the drill point breaks through the chassis and then makes contact with the backing plate to keep it going straight.
If you follow these directions for drilling a thin sheet metal workpiece, you'll achieve a round hole.

Wardsweb · « **Reply #16 on:** 25 Aug 2006, 10:06 pm »

Regardless of what method you choose, if you choose drilling or machining, do yourself a favor and get some Tap Magic for aluminum. I swear by this stuff. It even allowed me to use a hole saw in a drill press and get a clean hole. No binding, no chatter, just a clean cut. Now I don't normally use hole saws for metal but in a crunch once I drilled a 2-1/2" hole some 1/4" 6061 plate and the only thing that made it possible was the Tap Magic. I will also 2nd the use of uni-bits for smaller holes. Of course if you have a machinest buddy, an end mill is hard to beat unless you have a CNC machine.

Berndt · « **Reply #17 on:** 26 Aug 2006, 12:30 am »

Tap magic is great, but everyone has a can of wd40 about, and it will do the job fine.
It cools, clears the chips and though it might not have the lubricity of tapmagic it is easier to clean up.
I use wd40 when I table saw aluminum. I have cut up to 2" al plate on a table saw. Hole sawing is limited by the gullet depth on the hole saw, anything more than the gullet depth and you have to peck every few revolutions.

JoshK · « **Reply #18 on:** 26 Aug 2006, 05:34 am »

Quote from: Berndt on 26 Aug 2006, 12:30 am

Tap magic is great, but everyone has a can of wd40 about, and it will do the job fine.
It cools, clears the chips and though it might not have the lubricity of tapmagic it is easier to clean up.
I use wd40 when I table saw aluminum. I have cut up to 2" al plate on a table saw. Hole sawing is limited by the gullet depth on the hole saw, anything more than the gullet depth and you have to peck every few revolutions.

Actually just last night I was drilling a 3/4" hole in 1/4" aluminum faceplate. I used wd40 for lubricant and it was a real PITA and wasn't getting anywhere....but it was cool. Second hole I had to do I tried without the wd40 and it was easy as butter...but it made it a lot hotter. It was like the wd40 was lubing it too much and it wasn't grabbing and cutting and instead just sliding.