Rails compatibility

I’m about to place my HL15 order and got to wondering if the rails would actually work in my rack. I have a 21" deep rack that has thread holes instead of the caged nuts. Would I be able to use the rails with threaded holes?

You might need something like this to adapt the rails;

But also, IIRC the minimum depth for the short rails is 20 inches. I can’t see the exact dimensions, but it looks like if you add one of those adapters at each end of a rail the additional length would be more than one inch.

Here is one that looks a bit slimmer, but pricey, since they’re sold as singles, not as a kit;


Thanks. I forgot those things existed! The little extra length shouldn’t hurt anything.

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So, finally got the HL15 and got around to mounting things up today. Wanted to report back for anyone else that searches about the round thread holed racks:

you can use the supermicro short rails on a rack with round holes. You have to drill out (many may cringe at that) the threads on a couple holes but the rails themselves have threaded holes that your rack screws will thread perfectly in to and they align perfectly with the rack holes. You can even still put screws in to the HL15 ears to keep it in place.

If you look closely at the images on the supermicro site, you can see the holes: Supermicro MCP-290-00058-0N Rail Kit for 2U-5U Server Systems

I wasn’t thinking right on the adapters, for some reason I was thinking they’d go on the outside of the rack making it a little longer. So making it basically an 18" deep rack with those mounted, clearly did not work.

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Hey @keylooper! Glad to hear you were able to mount everything up to day. Any chance you have some photos? I’m trying to imagine in my head what you ended up drilling out to get this to work. I also have a round hole threaded rack, but I used the adapter set @DigitalGarden referenced above.

Yeah, here’s a couple different pictures.

So the holes I drilled out with a 3/16" drill bit. It was basically just enough to take off the threads so that when you put the screws in, they don’t grab the rack, but rather thread in to the rails.


I knew the screw holes were there, but I was thinking the tabs that are supposed to lock into the squared holes would be an annoyance. I guess the HL15 loaded isn’t that heavy and just supporting it with screws into the rails is ok.

I did think about that but figured if the adapters that only mount with screws is strong enough, then eliminating the adapters and direct mounting the rails would be as well. There is one more hole in the rail that I could add a third screw to but didn’t feel it was necessary considering most shelves and other mounts for threaded hole racks only ever use two screws and I’ve seen some ridiculously loaded shelves in my time.

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Gotcha! I understand now. I was thinking you drilled out the threads on the server rails. Drilling out the rack hole threads makes a ton more sense.

The adapters took me several attempts to figure out an orientation that worked for my rack. I don’t believe they are marked left or right so I kept putting them on in a way that didn’t allow holes to line up.

Here’s a few pics. I wanted to try to find some thumb screws for the rack ears, but the holes don’t quite line up with the ears.

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