Hidden threading on Computer Cases - How do they do it?

[Colinreay]

Hey everyone, I'm hoping your vast knowledge of manufacturing and designing cases can help me out here! I personally am enamored by the sleek anodized aluminum shells that Lian Li and Jonsbo do so well. I really love how there are no visible fasteners on the front, which allows for a cohesive and minimalist design.


I want to mirror this clean aesthetic in my own projects, yet am stuck on how case manufacturers can implement threads into their panels (particularly the front) without them being visible from the outside. A great example of this hidden threading is the Jonsbo U3.

Spoiler: Inner Shot

If you look on the inside, you can see mounting screws that hold the drive caddy as well as the side structural/side panel bracket to the front panel.

Spoiler: Exterior Shot

However, upon looking at the front, it is clear that you cannot see the fasteners. I've highlighted roughly where the traces of fasteners would be, yet it is blank.


So what fasteners can I use?

For the most part, I've only been looking at Pemnet so far.

Fasteners that I've eliminated/am pretty sure will not work.

• Standard Profile Self Clinching Nuts (You need a through hole for both panels and it sticks out)
• Flush Self Clinching Nuts (It doesn't stick out, but still needs a through hole and can't be covered up)

Fasteners that might work

• Blind Threaded Standoffs (Although they're too long (6mm min, when I need something like 3), can mount flush into the front panel, and can be powdercoated over)
• Concealed Head Standoffs (Again, too long, 6mm min)
• Spotfast Metal-Metal Fastener (This looks like a good bet, as you can install the flush mount side on the inside of the case (against another bracket you want to secure), and can be installed blind into the second sheet (the front panel), as per pg. 2 of the literature. However, I have two problems with these. 1, it is permanent, and Jonsbo doesn't do that. 2, it is hard to mount these once you bend the front panel, as the anvil could conflict with your bends. I've attached a photo for reference.)

Spoiler: Space Conflict

If I were to guess based on photos, Jonsbo uses some possibly custom concealed head standoffs (maybe 3 or 4mm), and then uses M3 screws + o-rings to secure inner brackets to the front panel. Thanks!

 

[jtd871]

Read this thread first: https://smallformfactor.net/forum/threads/stx160-0-the-most-powerful-atx-unit-in-the-world.934/

 

[Colinreay]

Read this thread first: https://smallformfactor.net/forum/threads/stx160-0-the-most-powerful-atx-unit-in-the-world.934/

Thanks for the suggestion! I have in fact read this thread before, and learned a lot from it. However, James never explained how to implement the type of hidden fastening method Jonsbo uses, and that I would like to know how to do. At first I was only looking at Pemnet, as that was the only manufacturer discussed in the STX 160 thread, but have not been able to find anything that seems to fit my needs (as I explained in the post.) On STX 160, he used standard profile self clinching nuts and through hole standoffs, both of which while great, may not or do not work for what I am trying to achieve.

 

[jeshikat]

If the sheet is thick enough, they very likely just drilled a blind hole (one that doesn't go all the way through the material) and tapped it.

 

[jtd871]

Sorry @Colinreay, I didn't get your meaning from the thread title. I had thought that you meant a pressed-in concealed-head standoff or something like that.

 

[Colinreay]

Sorry @Colinreay, I didn't get your meaning from the thread title. I had thought that you meant a pressed-in concealed-head standoff or something like that.

No worries!

 

[Colinreay]

If the sheet is thick enough, they very likely just drilled a blind hole (one that doesn't go all the way through the material) and tapped it.

Hmm, I could see that! However, Jonsbo uses 2mm thick aluminum, so I feel like that threading method might be a tad too weak.

I'm thinking more and more they do something like this:

1. Blind standoff
2. Blind standoff into the first sheet (or concealed)
   
3. Through hole in the second sheet for standoff body
4. Rubber O-Ring washer to allow screw head to cinch down on the two sheets
5. Add wide diameter wafer screw

 

[jeshikat]

2mm isn't thick enough for a PEMSERT that isn't visible at all on the exterior.

They may be adding the threading to a secondary piece of metal and welding that to the sheet.

 

[zovc]

The way I'd achieve something like this DIY, at least on wood, would be to use either a T-nut or a threaded washer.

I'm certain there have to be similar things one can achieve in metalworking, but you probably could just go as simple as welding a nut for a bolt to screw into.

 

[Colinreay]

The way I'd achieve something like this DIY, at least on wood, would be to use either a T-nut or a threaded washer.

I'm certain there have to be similar things one can achieve in metalworking, but you probably could just go as simple as welding a nut for a bolt to screw into.

Welding a nut is a great idea! I'll look into that more. Another thing that might work is welding a threaded stud instead and then fastening on brackets with a nut.

2mm isn't thick enough for a PEMSERT that isn't visible at all on the exterior.

They may be adding the threading to a secondary piece of metal and welding that to the sheet.

Ah ok. Is it too thin to be unable to be covered up by powdercoating if a blind standoff is used? If nothing else, I'd assume a concealed standoff would work, unless 2mm aluminum is also too thin to be milled into and still retain structural integrity when the standoff is pressed in.

 

[Necere]

Hmm, I could see that! However, Jonsbo uses 2mm thick aluminum, so I feel like that threading method might be a tad too weak.

I'm thinking more and more they do something like this:

1. Blind standoff
2. Blind standoff into the first sheet (or concealed)
   
3. Through hole in the second sheet for standoff body
4. Rubber O-Ring washer to allow screw head to cinch down on the two sheets
5. Add wide diameter wafer screw

That's exactly what they're doing (using concealed-head standoffs). @wahaha360 picked up one of their cases last time he was in China specifically to check that out.

 

[jeshikat]

Powder coating can cover it, though even with textured powder coating the outline of a blind standoff can still be visible at certain angles.

Concealed standoffs may actually work, I had the wrong number in mind and the minimum sheet thickness is 1.6mm to use concealed head.