Spartan: The 16.7L, full ATX tower case

Aibohphobia

aka James
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Feb 22, 2015
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I'm considering getting a trial of Solidworks and/or SpaceClaim for this project; hopefully I can draft it up and get a turnaround with Protocase inside 30 days.

SolidWorks would make more sense because you could export a Pack and Go file and it will make it much easier/cheaper for Protocase to prep the model for manufacturing.

And you could either model it from scratch (shouldn't be too difficult) or I can still export to STEP for you and you could start the SW model from that.

I also need to either find 1.25" diameter feet that accept an M3 screw from the bottom, or model one and have them made too.

They're just plastic with a thin metal exterior, but these are close to the right size: https://www.focusattack.com/35mm-aluminum-anti-slip-joystick-case-feet-set-of-4/

While I now want to use these, they are neither stocked nor listed by Protocase. I don't know what their min quantity to order would be. While I can buy 9 of them for $4 USD from swaco.com, I don't think Protocase would appreciate working like that.

ST160.0 used non-stocked standoffs, it just adds some extra lead-time for them to order the parts, but it's no big deal

It turns out the wider 6-32 standoff is .280" (7.112mm) while the wider BSO4-3.5M3-10 is only 5.39mm. I'd have to go up to an M4 thread to get back to 7.12mm; which defeats the purpose and won't reduce the unique screw count. SFX power supplies still require 6-32 threads, so I'd like to keep the motherboard standoffs as 6-32 threads. The height would also change from .375" (~9.5mm) to 10mm for what it's worth.

Ah, the thicker standoffs may only be necessary for M3, I only look at Metric so I didn't cross-check the diameter of the Standard parts.

The PSU comes with the #6-32 screws though so if you end up selling the cases you don't have to provide them.

You want to be careful about reducing the standoff height too much anyway, because it may cause the lip for the bottom edge of the motherboard IO cutout to be too short to bend without distortion. Also, the bottom of the tabs of the video card need room or they'll stick out past the frame and hit the panel.
 
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D_McG

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You want to be careful about reducing the standoff height too much anyway, because it may cause the lip for the bottom edge of the motherboard IO cutout to be too short to bend without distortion.
With the .375" standoffs, the IO cutout is .287" from the outside edge.

Rule Of Thumb: 2.5 * Material Thickness + Bend Radius.
2.5 * .050" + .050" = .175"
I currently have .112" (2.84mm) of margin.

Also, the bottom of the tabs of the video card need room or they'll stick out past the frame and hit the panel.
With the .375" standoffs, the PCI slots stick out .0250" (.635mm)
With the 10mm standoffs, the PCI slots stick out .0063" (.160mm)
I don't have an outside panel, but they do stick out by half of my material thickness.
 
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D_McG

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Update!

I've finally been able to source anti-vibration grommets with M3 screws for mounting two 2.5" drives to the bottom panel without going to China. Near impossible to get more of the M3 screws used in Lian Li cases (such as the NCASE M1). I needed a domestic source for any future production needs too.

Found ones that will work for a decent price in small or large quantities:
http://www.digikey.com/product-detail/en/keystone-electronics/767/36-767-ND/3465643


With these in mind I was then able to firm up the bottom panel design:



All PEM flange locations had to move to accommodate 1.25" (~30mm) feet with their PEM residing just inside the flanges (shown below).

After reviewing:
  • SFF-8201 (Form Factor of 2.5" Disk Drives)
  • SFF-8223 (2.5” Drive Form Factor with Serial Connector)
I had the locations for the drive mounts, but also had to increase the number of screws on the long edges from 3 to 4; so that the flange PEMs would be outside of the connector keepout zone for the SATA cables. There is now 16mm of space behind each drive for right-angled cables.

You can see from the image with feet attached that there's no room to make it tool-less with all 4 grommets and screws already attached to the drives and slid into keyholes; the feet are in the way.



When the drives are installed, the keyholes are concealed. There is 2.25mm between the fan and drive, 2.25mm between the psu and drive, and 2.66mm between the two drives.

 
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Aibohphobia

aka James
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Feb 22, 2015
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Near impossible to get more of the M3 screws used in Lian Li cases (such as the NCASE M1). I needed a domestic source for any future production needs too.

Do you mean the M3 screws with the shallow countersink? I've searched high and low and they're nowhere to be found. Surprisingly though, getting a batch of custom screws made in the USA isn't as expensive as you'd think.
 
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D_McG

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Hi everyone, I need your thoughts here.

I'm trying to find a good place for the USB 3.0 front ports. A design I keep coming back to, in order for the USB ports to be on top with their wires running in the right direction toward the 20-pin header, requires making the case 0.2" (~5mm) deeper. The extra space brings the distance between the fan and GPU to 0.5" (12.7mm) allowing for an 11.5mm panel mount USB cable.

This would increase the volume from 16.7 to 17.0 liters. I'm cringing at the thought, but it is the ideal location, and solves another issue. It has the added benefit of adding access to the SATA ports on EATX 12"x10.7" motherboards. 8mm allows for Silverstone SST-CP11B-500 SATA cables for the two bottom-mounted drives.

I've considered on the front, above the fans, but with the trim ring shown in the OP, there really isn't room to shift the fans down and still make it look good. I don't want to disrupt the front.

Let me know what you think, good or bad. The power button will be a stainless steel E-Switch PV6F240SSG-301 (white) just beyond the USB ports on top. I've hidden the top and bottom flanges in these images for clarity, and illustrated an EATX 10.7" motherboard.



 

iFreilicht

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Feb 28, 2015
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Hm, will you put this case on your desk or on the floor? In the latter case, I think that is a good position to put the ports in. If you want it on your desk, you could mount the USB ports below the mainboard in front of the PSU. And if you drop support for longer mainboards, then you could put one USB port behind the GPUs in front of the mainboard.

You could also add a flange to the top panel and mount the USB fans above the upper GPU in your render. This would limit the user to three full-size GPUs, but that's not a deal-breaker in my eyes. Using that position, it would also be easy to add more I/O like additional USB, Audio and buttons.
 

D_McG

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Would using a 90° USB front panel header (e.g.) help with clearance issues?
I came across these in my research. I couldn't find specs on the connector to see if it's less than 30mm, and the cable appears too short and rigid (being flat) to bend back down toward the 20-pin header at the front of the motherboard.

I searched for hours and hours for 90 degree panel mount USB 3.0 ports. Not finding something off the shelf.

On my drive to work today, it occurred to me that by making the case 0.2" deeper, with 0.5" of clearance between the fans and GPUs, that there would also be room for Quadro cards and a low-profile power adapter in between.
 

D_McG

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Hm, will you put this case on your desk or on the floor? In the latter case, I think that is a good position to put the ports in. If you want it on your desk, you could mount the USB ports below the mainboard in front of the PSU. And if you drop support for longer mainboards, then you could put one USB port behind the GPUs in front of the mainboard.

You could also add a flange to the top panel and mount the USB fans above the upper GPU in your render. This would limit the user to three full-size GPUs, but that's not a deal-breaker in my eyes. Using that position, it would also be easy to add more I/O like additional USB, Audio and buttons.
Are you thinking for the ports to come out the left side (stainless steel behind motherboard) or the right side through the acrylic?

I'd have the case on a desk. I think I can still mount audio jacks on top. The motherboard audio header is actually at the top of the case. I don't want to route a cable across the board, or else it will pick up noise.
 

iFreilicht

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Feb 28, 2015
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Are you thinking for the ports to come out the left side (stainless steel behind motherboard) or the right side through the acrylic?

The acrylic, sorry for the confusion.

I'd have the case on a desk.

Well in that case, I would suggest you put the ports toward the bottom, unless there's a risk of your desk getting so messy that you'll accidentally break them off.
 
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D_McG

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Hit a bit of a snag...

I don't think that there's enough clearance to maneuver cards in and out of the case; due to the tab at the bottom of the slot cover.

I've accounted for the retention tab at the top, and the higher height of the card itself, to pull it up 0.47" (12mm) but it needs to go higher in order to clear the motherboard's audio circuitry. You can see in the cross section image below that end of the slot cover hits the motherboard; let alone anything on its surface. I've tried pivoting the card a bit, but there's just not enough room.

(The Mac version of Sketchup 2017 broke anti-aliasing. I'll repost future images from my Windows machine with 16x AA)



I may need to consider making the upper flange removable. No idea how I'd secure it; it was structural.

Making the case 0.5" wider to 6" + acrylic kind of defeats the purpose. Nothing else in the case needs the spare height as is. A wider case would allow for taller GPUs and CPU heatsinks I suppose.

Thoughts everyone?
 
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Aibohphobia

aka James
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Feb 22, 2015
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Ah, the joys of case design.

That's basically the two simple solutions, either get the flange out of the way somehow (make it removeable, flip it the other direction, etc.) or make the case wider.

A more complicated solution would be to make the motherboard tray separate so it can slide out from the rest of the frame to get easy access to the cards.
 
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CC Ricers

Shrink Way Wielder
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Nov 1, 2015
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Aren't those bottom tabs supposed to go beneath the motherboard and between it and the back wall? AFAIK most motherboards don't line up flush against the back where the rear I/O cutout is... there is usually about 1mm of space in between which allows the bottom tab to go through.
 

Aibohphobia

aka James
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Feb 22, 2015
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The picture is showing that there currently isn't enough room to completely remove the card since those tabs don't even clear the motherboard, let alone the capacitors for the audio section.
 

D_McG

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Aren't those bottom tabs supposed to go beneath the motherboard and between it and the back wall? AFAIK most motherboards don't line up flush against the back where the rear I/O cutout is... there is usually about 1mm of space in between which allows the bottom tab to go through.
Hi, that's not the issue. You're right, there is .083" between the motherboard and the case. There are slots for the tabs in the case.

The issue is how to get the card into the case without the tab breaking off capacitors and such on the motherboard. The card flange, and the card itself, need to sneak under the case's outside flange, and then duck into the cutout for the retention flange. There doesn't appear to be enough room for the tab to clear motherboard components; typically in the audio section behind the PCIe slots.
 

D_McG

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The picture is showing that there currently isn't enough room to completely remove the card since those tabs don't even clear the motherboard, let alone the capacitors for the audio section.
I took the picture with the card at .45", but .47" clears the board. Would of course still need an extra .25" to .50" to get over any components, before the card would sneak under the outer flange.
 

D_McG

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Virtual hack saw time...

The best solution seems to be for the outer flange to just not be there:
  • Allows for cards to be inserted and removed vertically without any shenanigans.
  • Provides an opportunity to add a cover for the retention flange cutout.
  • Allows installation of oversized high-bandwidth SLI bridges that reside close to the backplane.
The cover would be attached to the acrylic in two places:




The screws for the acrylic line up front to back with exception to the one additional screw for the card cover.
 
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D_McG

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That works :p
I realized that there isn't much weight at the top to support. I'm still pondering the structural loss. The card retention flange bend should help distribute the weight down to the 80mm fans.

Interesting note, the case will be stronger after the fans are installed; given the large cutouts.
 
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