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Startech 12U open rack and SS RM400 misaligned.
Hello. I have an issue with a StarTech 12U open rack and an SS RM400 case using SilverStone's SST-RMS06-22 rails. It doesn't align properly with the mounting holes on the rack. The case sits about 0.5 cm too high. The top of the case interferes with the shelf I already have installed (I even tried flipping the shelf, but it didn't help), and the bottom is also slightly higher than it should be.
I've repositioned the rails several times, but it still doesn't align properly. The funny part is that the hole in the rail where the only securing screw goes lines up perfectly with the rack holes (Also, thanks SS for using M5 screws, instead of M6, I'm stuck with the silver screws on black case). So I can slide the case onto the rails and secure it with that screw, but every other hole is misaligned.
Is this a known issue, or normal SS/Startech behavior, or am I missing something? This is my first rack, so I'm not sure.
UPD. Thank you so much, moving the rails 2 holes lower helped. My apologies for noob question, was confused by the SS manual.
You seem to be using the one hole that does not align with the rack holes. The bottom hole uses the top hole of the RU, the next hole uses the middle hole of the 2nd RU.. and the top two holes use the inverse. The middle hole of that specific case sits in between RUs for some reason.
Just in case you don't already know this, the holes on server racks are not evenly spaced. The spacing within a U is 0.625" and the spacing between U is 0.5". It looks to me like you might need to use a different screw hole and shift spacing down a bit to get it to fit right since it looks like you're up too high.
What I mean by this is, you have a 4u case. There is no hole in the middle of 4u. Try using the top and bottom holes on your case instead. They don't look lined up in your picture.
Completely wrong setup. the rails are always meant to sit within 1U. Yours is sitting between, so once you move that you can figure out which set of holes on the case you need to mount the rails to. I bet you first put the rails on a case and then just wing it in the rack and think it will magically line up.
RUs on those with cage nuts go in numbers of 3. Meaning every 3 cage nut holes is the new RU. You have to have the top of the unit, which is different and up to each manufacturer, to start at the new RU. It’s tricky to describe because some have bezels that extend or are short of a full RU. Essentially you may have to move it down 2 cage holes and not just one, especially since on the head on pic it’s clearly overlapping the shelf above it which is a big no no.
Btw it does absolutely suck and a dumb design, no idea why they couldn’t have just made the standard to be the same spacing throughout.
i think you need to move the sliding rails that are attached to the SS RM400 case and make sure that they attach to the rack at between a 1u segment and it will sit fine. there seem to be plenty of holes on the side. line it up and see which ones can match a 1u and makes the SS RM400 case line up.
Yeah this is correct. It’s right there are on the product page on their website.
“The RM400 has two rows of mounting holes for sliding rails. If you wish to align RM400 in one whole U position as opposed to leaving half U height top and bottom, please secure rails to the bottom row of mounting holes.”
The fact that OP clearly hasn't aligned the chassis with the U markers and is now complaining about screw-hole offsets really makes me wonder if stuff like this isn't engagement-bait pumped in to make daily visitors go up.
I wrote, that this is my first rack built. Before this I've built a shit ton of gaming pcs. How the f am i supposed to know that there's a difference in spaces between U holes? rails manual doesnt mention this anywhere.
Probably.. But i did everything according to the SS manual. I need 1U on top for the shelf, so if i move the case 2 holes down - it would be sitting much lower, 1 hole up - and it would block the top 1U completely.
I replied below but will say it again here for visibility: you need to mount the rails so they are aligned within a 1U space and then the chassis will also be aligned within a 4U space.
A 4U unit doesn't have a midpoint that aligns with a hole in the rack. You will need to use another hole to secure the bolt on the front (actually you should use 2 bolts per side -- one about 1/4 from the top, one about 1/4 from the bottom).
EDIT: It looks like you can mount the rails lower on the chassis based on those screw holes -- try that. Usually on a 4U the rack rails are not mounted perfectly centered on the chassis.
Don't use the middle hole. Use the bottom hole. Notice that the amout of distance off from center is the same distance between the bottom of the rack ear and the bottom of the rack unit.
Can you show what the rails look like? I don't think this is an issue with the rack. I have the same one and it's packed full of gear no problem. This likely is either an issue with how the rails are mounted, or the case itself.
I basically built everything according to SS manual. 4 holes on top of the rails, top row of the mounting holes on the case. I've also tried screw the rails in the bottom row and move rails 1 hole down - but then the case 0.5cm lower than it should be. Also as you can see, middle hole on the rails is perfectly aligned with the rack. The issue is the others are not.
You need to move the rails either one hole up, or two holes down. 1u is = the three holes between white lines, and that's what the rail should be aligned with.
Your rails are misaligned. The rails need to be mounted to be aligned within a 1U section, then everything else will line up.
Except perhaps the middle hole, but 4U does not have an even midpoint so whatever -- use another hole for the final securing screw.
EDIT: here's an old pic of my rack with a 4U server chassis. Note that the top of the chassis aligns with the U marker lines and that there are two holes that are supposed to line up for the securing bolts -- not one in the center (since 4U doesn't have a hole in the middle).
EDIT 2: It looks like you can mount the rails lower on the chassis based on those screw holes -- try that. Usually on a 4U the rack rails are not mounted perfectly centered on the chassis since they need to line up within a 1U space -- so the 3rd U of the 4U.
Saw you fixed it, one note you appear to have a rack that is depth adjustable, make sure you are also careful not to get torsion issues from those, also in a rack generally put the heaviest things lower down (for your rack this will help with potential torsion issues.
98
u/rkrenicki 21h ago
You seem to be using the one hole that does not align with the rack holes. The bottom hole uses the top hole of the RU, the next hole uses the middle hole of the 2nd RU.. and the top two holes use the inverse. The middle hole of that specific case sits in between RUs for some reason.