I built a 10 inch mini rack from aluminium extrusions | Hacker News Reader

I built a 10 inch mini rack from aluminium extrusions

louwrentius.com

106 pointslouwrentius49 comments

These aluminum extrusions are called T-Slot, or as McMaster-Carr calls it, "T-Slotted Framing". Very common in industry; we have it everywhere on the Boeing factory floors. Not cheap, but very durable and reusable. Highly recommended.

Check it out starting on page 2240 of your McMaster-Carr 132 catalog. They have all kinds of things you can mount up like monitor arms. It's an erector set toy for engineers. ;)

https://www.mcmaster.com/products/t-slot-framing-components/...

Misumi sells it, and they have an online tool to configure almost anything you want in 3D, including brackets of your choice, fasteners and accessories (like panels, hinges and handles). Then, you can order all of the parts to make your creation with 1 part number.

Makerbeam is also nice, they sell a 5x5mm, 10x10mm and 15x15mm version (normally the smallest cross section of t-slot is 20x20mm). The 5x5mm version is comically small when you hold it in your hand. When you order a set, it comes with tweezers to pick up the screws which are size M1.2.

It's often called 8020 aluminium if people are looking for alternative vendors.

Always a good day when I get to look at the McMaster catalogue

Do we have something similar to McMaster-Carr in Europe. I am looking at maybe Germany, Denmark, Sweden , North Europe and Scandinavia?

Similar - no (I'd be glad to be proven wrong), but you can find some small suppliers focused on specific niche like https://www.motedis.com if you need the profiles.

I didn't originate this idea, but if you're curious about other options... I found success using an IKEA Helmer for my home lab.

https://www.ikea.com/us/en/p/helmer-drawer-unit-on-casters-b...

https://github.com/bwann/homelab documents this sort of setup. Looks great!

I have a couple of these, they are made of a light gauge sheet metal; the inner dimension is ~9.75", wider than the 10" standard hole spacing; and I don't think they would be very structurally sound if you were to remove the back panel. Doesn't seem very well suited to me.

IKEA CORRAS FTW. https://www.neilvandyke.org/machine-learning/super-in-ikea-c...

Thanks for sharing. I’m running a lack rack for 15 years, would have been fitting

can you share a pic?

First time I saw that was a dude who made 6x core2quad q6600 render farm

Why use the original power bricks, with the space claim and awful routing, instead of just going to a single dc/dc... either directly if no individual power control is needed, or to a relay block or switch block if automated / manual individual control is needed?

I remember seeing this great video where they built their own power supply for their mini rack. Quite a project but ended up being a pretty cool solution to the problem.

https://youtube.com/watch?v=8tTG0TBM7ts

https://www.reddit.com/r/homelab/comments/1qh13nu/i_made_a_p...

I bought an 800w GaN USB-C charger from AliExpress (https://www.aliexpress.com/item/1005009093660588.html) and a handful of USB-C to barrel jack adapters. They're powering 2 EliteDesk G2s (35W) and 2 EliteDesk G3s (65W); not had any trouble so far though the GaN charger does run a bit hot (which I resolved by putting a fan under the charger).

Admittedly I can't be sure of the long-term reliability of the GaN charger, but its been running problem-free for over a year now.

One option is to stick a mini-UPS in-between the wall the devices. Such a thing is internally a handful of lithium cells and some DC outputs.

For powering a handful of things that consume less than 100W they are quite useful because they typically provide 2 or 3 DC outputs, and replace between 2 and 4 power bricks.

They also provide an hour or two of backup, quite useful in my country where the power sometimes goes out for a bit.

The downside is that I cant find decent ones in my country, and so I end up replacing mine every 2-3 years.

I haven’t found a solution for a single DC power supply I can connect to the systems. Maybe I have to solder something together myself.

Man, I spent a lot of time looking for something like this when i bought my NAS and got annoyed with all the power bricks. Guitar players use them[0] to power their several guitar pedals, but the polarity, voltage and plug form factors are all the same, as far as I know. The various devices i have use slightly different plugs, polarities and i think not all are 12VDC.

I'm very surprised that nothing like this exists in the tech/IT space. There can't be that many form factors, voltages, etc. to deal with.

[0] I think something like this: https://www.monoprice.com/product?p_id=600062

Most guitar pedals are 9V DC but not all.

Some are 12v. Some will take 18v. I have an oddball that takes 9V AC. Some are 9V DC but flip the positive and negative. It can be a mess too.

The product you link to has outlets for 9V, 12V and 18V.

If you stuck to one PC manufacturer, I’d imagine you could have your wish. Dell laptops were the same 19V and same DC pin for years and years.

I thought USB-C PD would save us but it has a few pitfalls, apparently.

Pedal polarity is inverse of typical barrel plug polarity though.

Meanwell is the standard answer for this sort of thing; something in the SD-500 family or sized/optioned as you need. You'll have to do the connectors yourself; you may be able to find junction-post-to-barrel-plug leads of the right size and length off the shelf, but I'd be surprised, and soldering them would take less time than shopping for them.

The HP's power-supply is 19.5V:

https://www.ebay.com/itm/235241551377

The SD-500 is available in 12V, 24V, and 48V, none of which adjust to that range:

https://www.meanwell.com/Upload/PDF/SD-500/SD-500-SPEC.PDF

Also, not sure why you're suggesting a DC-DC supply here? His input is AC.

Probably the idea is to have one big AC-DC PSU and then separate DC-DC regulators for each box from that rail.

Thank you

An old PC ATX power supply is great for most things that use 5/12V. You get the 2 most common voltages for network gear, with plenty of capacity and efficiency (with a decent PSU.)

You do have to solder, though I wouldn't be surprised if one can find sata power to barrel adapters on AliExpress.

They make breakout boards that mate with the main ATX motherboard connector on the PSU. Bonus that some of them even include fuses.

And at that point, why not just chop up an old ATX case to house everything, assuming there's clearance.

This looks good: I've got three HP NUCs like in TFA + three Pi on my desk (got more than that altogether) and it's indeed a cable mess.

> Aluminium extrusions are bars with a groove on all four sides. These bars have a standard format and you can slide all kinds of equipment in there and lock it in place with set screws. It seems to be used a lot for home made 3D printers, CNC machines and whatnot.

They're also called "T-slot" and 80/20 (from the brand).

https://en.wikipedia.org/wiki/T-slot_structural_framing

Plenty of free 3D models for tiny parts for those that can be printed at home (careful though: most won't hold much weight).

Built something fairly similar about 15 years ago. The cheapest way by far to do it is get everything you need off Aliexpress except the alu sheets which you can typically get as offcuts from local manufacturers, I was lucky enough to pick up some odd shapes that had been used for signage for next to nothing that I could cut to the right size. Since you need to buy bags of 50 or more of the M5 fixings, you an bundle them up and recover some or all of the cost by selling them locally once you've used the few you need.

I got the TecMojo 10" 6U rack[1] from Amazon for less than $100. It's great, and even came with 2 HTML USB adapter boards (I think for some variety of R-PIs?)

Getting something with actual, standard rack-mounting points is worth it because you can use the huge variety of 3D printed hardware to match it very easily.

I agree with the other commentators that power bricks are a problem though. My setup is fanless and silent which is an extra challenge.

[1] https://tecmojo.com/collections/mini-server-rack

It would be cool to design custom aluminum brackets for the fans. However I found that although ordering 3D prints is very cheap, using (for example) PCBWay for CNCing something out of aluminum is very expensive.

Try to avoid milling unless you absolutely need it. Better to go 2D with some tolerance and print small adapters, or use standard T-slot hardware, to connect it. It's often educational to browser McMaster just to get a feel for what standard parts even exist.

For a bracket I would look at a laser or waterjet service. Sendcutsend is one of the more well known web shops and the pricing is OK for the convenience. Also look out for local places that are linked to education. Some libraries even have laser cutters. One shop near us will do simple jobs for machine time + material cost, like you give them a DXF and they'll cut acrylic for a good price. Other option for metalwork is to join a makerspace. The dues are often very reasonable vs trying to get a lathe into your house.

Thanks for the tips!

I do some FOSS work with bootloaders and would love a cheap setup where I could leave boards running and have remote access to their UART/SPI/power.

Occasionally I need to be able to get physical access to it too.

I use esp32 for the remote UART/SPI, but don't really have a good setup for keeping a few projects tidy, and with the ability to move it from its remote location (a bookshelf) to my desk for physical access.

Does anyone know of any cheap and dense way to store these projects/boards?

Nice writeup!

Always thought extrusions were expensive. At least had found a company custom cutting them but the price was something like 20x what you got.

They are usually ludicrously expensive. But since Chinese manufacturers started using them for various small machine (3d printer, engraver...) frames, there's a now finally a cheaper supply.

we call that a shelf.

O call it shelf for stupid HP shitboxes, with no redundancy, high consumption and low performance.

I bet these are old corporate scrap metal with something horrid like i3-9100T. Nothing a wall mounted Chinese NUC with 12-13th gen i7, 2x32GB DDR4, 2x PCI-e 4.0 NVMe, 2x LAN can't do much better for price of that NOT-rack and fraction of electricity.

Which part of this is a "rack"?

the whole thing?

Which part do I mount one of these 10" rack-mount switches[1] to?

[1]: https://mini-rack.jeffgeerling.com/#network-gear

Any of it. TFA references https://loganmarchione.com/2025/09/homelab-10-mini-rack-v2/ which uses standard 10" shelves.

I think the issue is that these arent close to rack specification. So its a rack in that its a set of shelves, but its not a Rack as the technology industry would define it.

That’s a good looking build.

I considered going the 10 inch route too but ultimately decided on a small 19 mainly because I also wanted to fit a ATX build in there and most gear is 19 standardised

Have you taken grounding into consideration?

The chassis is not connected to ground, tbh. Not really.

I'm no expert but to my knowledge metal cases always need to be grounded. Which is what I did with my 10" rack. I just bought a socket with a ground connector from an online store, although I'd be curious which exact cable is best practice. I don't have many things connected there anyway and the power supplies are outside of the rack.

FWIW the topic is quite a rabbit hole and for non-mobile metal cases (e.g. screwed on the wall) technically even an electrician seems to be needed.

Awww, its so adorable

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