Precise holes in a premade aluminum box, what's the best approach? - Page 1
Forum section: electronics / beginners

author: A_Ghost
author_rank: Newbie
timestamp: March 31, 2025, 08:13:24 pm
content: I've been researching the best way to tackle this for a while now, and I'm hoping you fine folks can help steer me in the right direction.The box (victim) in question.https://www.mcmaster.com/75895K54/I need to modify 10+ of these for a work project, so I'm trying to avoid as much manual labor as possible (especially considering how my prototype ended up looking).These are my current potential solutions.A CNC mill would be ideal(?), but it is cost-prohibitive to purchase, and the closest local business that offers custom service is over an hour's drive from work.A CNC router is much more attainable cost-wise, but I haven’t researched enough to know which would be a good fit for this application. Also, since the box is 10 inches tall, it seems like most of the CNC routers wouldn’t be able to fit it. Though, I’m sure there is a way around the height restriction.3D printed guides for a router or dremel. I’ve read a lot of conflicting discourse over if a dremel/router is a good tool for this. I know they’re not the “right” tool for the job, so any thoughts or insights on this are very welcome.Drills, files, jigsaws, nibblers, oscillating tools, etc. I can make it work with these as I’ve already prototyped one box with this method, but it’s pretty time-consuming and I know I’ll never get the quality I’m aiming for.If I missed anything, I’d love to hear it, or if there’s a different approach entirely that I’ve not considered.Thank you for your time.

author: TimFox
author_rank: Super Contributor
timestamp: March 31, 2025, 08:21:21 pm
content: Please specify the hole you need.Precision round holes can be obtained using a reamer after the appropriate standard drill.

author: A_Ghost
author_rank: Newbie
timestamp: March 31, 2025, 08:36:49 pm
content: Sorry! I should've been more clear. There's a handful of circular holes ranging from 3mm to 16mm, which aren't an issue. The real problem is the 2 rectangular cutouts. I don't have the sizing with me right now, but I'll add a picture and update the post with the sizing when possible.If I had to guess, I'd say they're roughly 90mm x 45mm and 50mm x 35mm.

author: Analog Kid
author_rank: Super Contributor
timestamp: March 31, 2025, 08:56:03 pm
content: I don't know a whole lot about this technology, but I've heard that water-jet cutting is very precise and maybe not too expensive. (I'm thinking for the rectangulare holes; the other ones could probably be just drilled.)You could look into whether there's a local machine shop that has such a cutter. I know where I used to live (SF Bay Area), there was at least one maker space that had a water-jet rig.

author: langwadt
author_rank: Super Contributor
timestamp: March 31, 2025, 09:03:39 pm
content: carbide wood tools usually work just fine with aluminium, so router with guide bushing and a template should work

author: Smokey
author_rank: Super Contributor
timestamp: March 31, 2025, 09:14:52 pm
content: 10+ as in you need to make 11 pieces one time then never again, or like some a month forever?That is a pretty basic box design. If this is a reoccurring thing, you could have a sheetmetal shop just make you a custom box of similar design with the holes already cut.

author: Analog Kid
author_rank: Super Contributor
timestamp: March 31, 2025, 09:36:09 pm
content: Quote from: langwadt on March 31, 2025, 09:03:39 pmWellll, yes and no.You can certainly cut aluminum safely with carbide tools; clean cuts are another thing, though.Depending on the specific cutter used, you're likely to end up with a lot of burrs and roughness that will have to be cleaned up. Because aluminum is so soft it tends to spall rather than cut cleanly.

author: themadhippy
author_rank: Super Contributor
timestamp: March 31, 2025, 10:01:25 pm
content: If its ally just get yer hacksaw and file out

author: audiotubes
author_rank: Regular Contributor
timestamp: March 31, 2025, 10:10:41 pm
content: Quote from: A_Ghost on March 31, 2025, 08:13:24 pmWhat about something likehttps://www.mcmaster.com/products/square-hole-knockout-punches/

author: Analog Kid
author_rank: Super Contributor
timestamp: March 31, 2025, 10:42:08 pm
content: Quote from: audiotubes on March 31, 2025, 10:10:41 pmProbably not, as the OP mentioned this about their holes:QuoteOther than that, those punches are very good tools to make clean holes in sheet metal.

author: langwadt
author_rank: Super Contributor
timestamp: March 31, 2025, 10:47:36 pm
content: Quote from: Analog Kid on March 31, 2025, 09:36:09 pmyou must be using dull tools

author: vk6zgo
author_rank: Super Contributor
timestamp: March 31, 2025, 11:13:28 pm
content: Quote from: audiotubes on March 31, 2025, 10:10:41 pmSuch things were widely available way back in the 1950s (probably 1940s), when the default way of building electronics was to use a metal chassis.There are probably still some gathering dust at the back of old electronics hobbyist's tool cupboards,

author: TimFox
author_rank: Super Contributor
timestamp: March 31, 2025, 11:27:24 pm
content: Quote from: vk6zgo on March 31, 2025, 11:13:28 pmRound-hole punches are readily available at reasonable prices, but rectangular and D-shaped punches are far more expensive.

author: Analog Kid
author_rank: Super Contributor
timestamp: March 31, 2025, 11:34:37 pm
content: Quote from: langwadt on March 31, 2025, 10:47:36 pmNope. Sharp tools.Try it yourself: use a good (fine-tooth) carbide blade in a table saw and cut some aluminum. It'll make a mess.Same with router bits. The metal's so soft that instead of forming proper chips, it bends and deforms. Plus it tends to "grab" the blade.

author: anvoice
author_rank: Frequent Contributor
timestamp: March 31, 2025, 11:59:20 pm
content: Snapmaker sells the A350T 3 in one 3d printer router engraver which should fit your box, but it's expensive ($850). You might be able to get away with something likethis. It's a cheapish CNC router with from what I can see no guides or ballscrews below the base, so you could remove said base and fit your box underneath.Finally, if you have access to a 3d printer, you could print a thicker guide, tape/glue it to the box temporarily, and use a cheap hand router to make the cuts against the guide.If (I doubt it) you need perfectly square holes (that is, no rounding at the corners), it's either an expensive machining process or a square file and some effort.

author: jpanhalt
author_rank: Super Contributor
timestamp: April 01, 2025, 12:02:25 am
content: Any small mill with a modern DRO and a mounting jig (bars clamped to the table) on the table could easily do 10.Edit: corrected spelling of jig.

author: temperance
author_rank: Super Contributor
timestamp: April 01, 2025, 12:18:30 am
content: A carbide tool made for wood spinning 15...30K revs/min to cut into 1 or 2 mm aluminum...Because of the sharp cutting angle of carbide tools made for wood the cutting tool will try to cut trough the aluminum at once the moment the tool touches the aluminum. Good luck, and make sure the emergency number is dialed in because the router will work with you instead of you working with the router when the cutter slams trough the aluminum in a microsecond. Those routers are over 500 W (mine is 700 W). You can't stop those when they grip into something.

author: fourfathom
author_rank: Super Contributor
timestamp: April 01, 2025, 01:12:29 am
content: Quote from: Analog Kid on March 31, 2025, 11:34:37 pmI'm using a Shapeoko CNC mill to cut holes, relief areas, and rectangular holes in a 19" aluminum powder-coated faceplate, I recently did a batch of ten faceplates using a single inexpensive carbide bit (1/8" dia) from Amazon:https://www.amazon.com/gp/product/B078KCSZQV/. Clean results, no clogged bit. I've clogged and broken bits before, but what made the difference is "feeds, speeds, and lubrication". I'm using WD-40 for the lubrication, which I am told is not the best for this, but it's been working for me. The CNC mill uses a pretty common Makita router to spin the bit, do I don't see why you can't do this using a guide instead of the CNC mill (but the Shapeoko is fairly inexpensive).Here's a video of my faceplate being milled:

author: Poroit
author_rank: Frequent Contributor
timestamp: April 01, 2025, 05:43:12 am
content: I have used the following successfully for many projects:HP-1 PowerMan Jnr Hole Puncherncpmk-10 hydraulic notching toolhttps://www.stainelec.com.au/hole-punchers.phpThe cost a bit initially....... but a good investment if you are doing future similar jobs as they save hours of work.

author: BILLPOD
author_rank: Frequent Contributor
timestamp: April 01, 2025, 12:41:20 pm
content: I am still reeling at the $322 price of an 8"X6"X10" box........

author: vk6zgo
author_rank: Super Contributor
timestamp: April 01, 2025, 02:21:16 pm
content: Quote from: TimFox on March 31, 2025, 11:27:24 pmRectangular ones were more expensive in the1960s when I bought one, but not outlandishly so!

author: langwadt
author_rank: Super Contributor
timestamp: April 01, 2025, 03:22:12 pm
content: https://youtu.be/-gboj2XhuW0?si=cV7Nlpc3Yp2XnCs8&t=118

author: jmelson
author_rank: Super Contributor
timestamp: April 01, 2025, 03:29:45 pm
content: Is there a makerspace in your area? Some of them have milling machines, either manual or CNC that could make quick work of the rectangular cutouts, as well as the round ones.Jon

author: Raj
author_rank: Frequent Contributor
timestamp: April 01, 2025, 04:08:12 pm
content: Easy solution: A press with dies (could be hydraulic or inertial screw press etc.)

author: reboots
author_rank: Regular Contributor
timestamp: April 01, 2025, 06:11:33 pm
content: McMaster-Carr does not mention the wall thickness of that box. However I can tell you that a large, hollow sheet aluminum box with a hinged lid will be difficult to machine with a lightweight CNC router. The metal walls and lid will tend to deflect and vibrate, resulting in a poor finish and destroying carbide micro-tooling.Knockout punches would give a good result, but as others have noted available sizes and cost may be limiting factors. Step drills for round holes and an air-nibbler for square cutouts might also work well, but will be more labor intensive.You don't mention whether your cutouts need to be in the side walls, the lid, or both. If you can arrange them in groups, one option might be to fabricate subpanels through a third party like Front Panel Express. The cutouts could be precisely defined, and the panels could include colors and lettering. Each panel would mount in one large cutout which wouldn't need to be cosmetically perfect.https://www.frontpanelexpress.com/

author: jpanhalt
author_rank: Super Contributor
timestamp: April 01, 2025, 08:17:10 pm
content: How about drilling from the inside out? If not possible, just fill with water and freeze to -20° or lower. Then drill/mill from the outside. If you don't like water, use kerosine, water-based machining fluid, etc.Using punches doesn't help solve the ultimate problem of getting the holes accurately positioned. You will still need alignment.

author: calzap
author_rank: Frequent Contributor
timestamp: April 01, 2025, 10:00:44 pm
content: Have you looked into a custom metal box maker, like Bull Metal or Dalsin? They can make a box of whatever size and material you want with holes, doors, etc. like you want. Might be cheaper and less hassle in the long run, especially given the price for the box alone from McMaster.Mike

author: Analog Kid
author_rank: Super Contributor
timestamp: April 01, 2025, 10:55:27 pm
content: Quote from: fourfathom on April 01, 2025, 01:12:29 amNice.WD-40 (= Stoddard solvent) should be fine as cutting fluid; it's not a great lubricant for other purposes (becomes sticky over time) but should work well as a light lube.I didn't see any rectangular holes there. Should be no problem with that small bit; the radiused corners could be easily squared up with a rectangular cross-section file.BTW, one thing WD-40 is really good at is rust prevention. Not removal, but protecting metal against corrosion. (For removal you'd want to use something with phosphoric acid in it, like Naval Jelly.)

author: jpanhalt
author_rank: Super Contributor
timestamp: April 02, 2025, 12:51:33 am
content: This is what I use in my shed to protect stuff:https://www.amazon.com/KELLOGGS-PROFESSIONAL-57800-Accessories/dp/B000BXKY8EThat and LPS 3 are much better than WD-40 for preventing rust, IMHO. I switched to that in the 1990's and have never switched back.As for oil, 20 SAE (ND) is great. For something that sticks (as for ways in a lathe) use a good quality of bar and chain oil.Both are cheaper than "purpose-made" stuff with different labels.

author: vk6zgo
author_rank: Super Contributor
timestamp: April 02, 2025, 04:22:19 am
content: At one place I worked, they sent stainless steel panels away for laser-cutting.It was nice & accurate but I was never impressed, as the edges looked like they had burned, with a thin layer of stuff that looked like soot, but was hard.It might work better on aluminium.

author: Kasper
author_rank: Frequent Contributor
timestamp: April 02, 2025, 05:05:45 am
content: Quote from: calzap on April 01, 2025, 10:00:44 pmI tried SendCutSend recently. Great guides on their website for first timers. With holes and anodized finish, it cost about 50% more than a similar box on digikey, without holes. That was for 5 pcs, price would be more competitive with higher quantity.

author: Kasper
author_rank: Frequent Contributor
timestamp: April 02, 2025, 05:08:47 am
content: Quote from: A_Ghost on March 31, 2025, 08:36:49 pmTry local sheet metal fabricators that offer water jet cutting.

author: Analog Kid
author_rank: Super Contributor
timestamp: April 02, 2025, 05:55:27 am
content: Quote from: Kasper on April 02, 2025, 05:08:47 amAmen to that. That's still my preference.Amazing how clean those cuts are.

author: A_Ghost
author_rank: Newbie
timestamp: April 02, 2025, 02:15:02 pm
content: Quote from: Smokey on March 31, 2025, 09:14:52 pmI'll need to make a bunch all at once, and then I'll have to make one or two a month, assuming demand doesn't increase.Quote from: anvoice on March 31, 2025, 11:59:20 pmA 3D printed guide was one of the options that was most appealing to me. I was mainly concerned about the viability of cutting aluminum with a router or Dremel and if I were to attempt it, what were some pitfalls or issues I would need to avoid. Thankfully, there's been a solid bit of discussion in this thread about that (thanks everyone!)The holes can have rounded corners.Quote from: BILLPOD on April 01, 2025, 12:41:20 pmSame here. It seems outrageous, but I needed something short-notice. The cost per unit, the fact that it's not quite the right size, and the fact that I have to modify it are definitely making me consider investigating what a custom box would run. I didn't have the time before, but I do now. I figured fabricating a bespoke aluminum watertight box would be more expensive than buying a ready-made part.Quote from: jmelson on April 01, 2025, 03:29:45 pmThe nearest makerspace with a mill is about the same distance to the shop, but that is an option.Quote from: reboots on April 01, 2025, 06:11:33 pmI was worried about the deflection and vibration as well. Even with hand tools, the panels would flex, making working with them a headache. For this version, I was trying to avoid putting any holes in the lid as it seemed like I'd just be making it worse for myself.I haven't heard of Front Panel Express. I'll definitely be giving them a look, especially for future projects.Quote from: jpanhalt on April 01, 2025, 08:17:10 pmI actually ended up drilling from the inside out several times. It was definitely a headache and not something I want to have to do over and over again. Accurately positioning the holes was the biggest headache of doing it by hand.Quote from: calzap on April 01, 2025, 10:00:44 pmI've not, but it's something I will check out, as I've seen that suggestion here more than once. Is there a specific company you'd recommend over another, or would I be better off finding someone local to do this?Lastly, here are two not-so-great pictures of the box as I worked on it. That could add some better context. Feel free to judge openly and thanks to everyone who weighed in so far, this has been incredibly educational and helpful.

author: Langdon
author_rank: Frequent Contributor
timestamp: April 02, 2025, 02:25:51 pm
content: CNC?A drill press might be good enough if you are very careful.

author: Analog Kid
author_rank: Super Contributor
timestamp: April 02, 2025, 10:42:58 pm
content: Quote from: Langdon on April 02, 2025, 02:25:51 pmI don't think so.To drill clean holes you'd need some backing behind the metal; wood would do fine.Problem would be holding it in place against the pressure of the drilling:you'd need to build some kind of blocking inside the box, which would be a pain in the ass.Plus it's a big box, so you'll need a big drill press, not just a little benchtop one (like mine).

author: incf
author_rank: Frequent Contributor
timestamp: April 03, 2025, 12:01:59 am
content: I'm sure someone has already suggested roughing out a hole with something like a cheap hole saw or punch, and then installing a laser cut panel (which is quite affordable via sendcutsend)Then it's just a matter of "glue vs screw"*a hole saw can work in thin metal, but you better have a beefy low speed drill press to hold it

author: 5U4GB
author_rank: Super Contributor
timestamp: April 03, 2025, 02:15:51 am
content: Quote from: TimFox on March 31, 2025, 08:21:21 pmAlso how much you're willing to spend to do this. For example one cheap way to do it would be to make a jig out of ply, clamp the jig to the outside and another piece of ply to the inside so the metal is sandwiched in place between them, then run a router with a carbide cutter around the jig (disclaimer, I'm used to working with wood, not sure if you can cut metal the same way). This would cost very little.

author: Dougmc
author_rank: Contributor
timestamp: April 03, 2025, 02:29:02 am
content: Contact bud industries for quotehttps://www.budind.com/electronic-enclosure-modifications/

author: squadchannel
author_rank: Frequent Contributor
timestamp: April 03, 2025, 03:13:28 am
content: round holes can be done with a drill press. square holes can be done with a nibbler.I think the case is Hammond EJ1086AL. It is 0.08in (2.032mm) thick, so it might be difficult with a nibbler.

author: fourfathom
author_rank: Super Contributor
timestamp: April 03, 2025, 04:03:17 am
content: Quote from: Analog Kid on April 01, 2025, 10:55:27 pmThanks! There are two rectangular holes at the far end of the panel (yes, with 1/8" rounded corners). Here's the front-side of the finished panel, with laser-etched logo and legends:

author: Coordonnée_chromatique
author_rank: Frequent Contributor
timestamp: April 03, 2025, 05:48:49 am
content: Quote from: Analog Kid on April 02, 2025, 10:42:58 pmA pice of wood is not homogenous and can bend the drill bit during the process, in aeronautics we use solid carbide drill bits at 10K rpm without any backing.

author: Analog Kid
author_rank: Super Contributor
timestamp: April 03, 2025, 06:38:17 am
content: Quote from: Coordonnée_chromatique on April 03, 2025, 05:48:49 amWhat are you drilling? and what kind of drill bits (besides being solid carbide: twist bits? brad point? something else?).

author: Jeroen3
author_rank: Super Contributor
timestamp: April 03, 2025, 06:50:48 am
content: For customisations in enclosures like this it's best to buy them directly from the manufacturer or wholesalers with cutouts.If your ecad tool does the panel design these files can often be sent to them directly. Such as eplan.If not, they can take other formats or have an online tools.For example, Rittal has RiPanel. Our wholesaler owns a Rittal cutting machine so they can do enclosures quickly with basically no startup cost.I'd expect Hammond/Schneider to be able to do this as effectively as well.Custom square cutouts without automated laser/water cutting are almost always sloppy.Stainless is easily doable with a water cutting due to it not being painted or rusting. But a welded box like this I'm not sure, we've only done it for larger cabinets where all panels come off.

author: Coordonnée_chromatique
author_rank: Frequent Contributor
timestamp: April 03, 2025, 07:29:11 am
content: Quote from: Analog Kid on April 03, 2025, 06:38:17 am7075 2mm of thickness airplaine panels.https://ascentaerospace.com/fr/products/automation/It is one solution to make a hole in a thin material, a rigid tool and at high speed, there are a lot of solutions.... but the piece of wood is