APC 0M-756H 2U UPS slide rails - fasteners?

[andrewbedia]

I bought one of these recently, but it didn't come with the fasteners. Any idea what these are threaded for? It's not M6, which is all I have. M5, maybe?

Figured I'd ask here before bringing one of them to the homeless despot / hazard fraught to look for fasteners that fit the inserts. Can't find this on google or in APC's documentation

Answer: M5

 

[kevindd992002]

Hi. Where did you get the M5 answer? Or did you test this yourself?

 

[kevindd992002]

Any updates here please? I'm reading that they're either 10-32 or 10-24 screws so I'm really wondering where you got the M5 info.

 

[nabsltd]

Any updates here please? I'm reading that they're either 10-32 or 10-24 screws so I'm really wondering where you got the M5 info.

I just pulled one of the bolts and tested. It's either 10-32 or M5-0.8. Since 10-32 is M4.8260-32 and M5-0.8 has 31.75 threads per inch, they are almost interchangeable.

 

[kevindd992002]

I see. Isn't an M5 too tight of a fit on a 10-32 screw hole though?

If I needed a bolt to secure my UPS to this rail, what length should I be getting?

 

[nabsltd]

There's a lot of slop on nuts or other "female" threads. The extra 0.174mm in diameter of the M5 bolt isn't enough to stop it from going into a 10-32.

You use two bolts per rail (front and back, so 8 total) to fasten the rails to the the rack. Then two bolts per rail to fasten the UPS rack ears to the front of the rail. Four of the bolts must be flat head and countersunk to fasten the front of the rail to the rack and allow the rack ears to stay flush. The rest can be any style head.

All bolts should be at least 20mm long.

If this sounds like AI instructions, it's because I've installed a bunch of these rails and UPS, and also used the rails without having the original hardware, and instructed other people at my work how to do it.

 

[kevindd992002]

There's a lot of slop on nuts or other "female" threads. The extra 0.174mm in diameter of the M5 bolt isn't enough to stop it from going into a 10-32.

You use two bolts per rail (front and back, so 8 total) to fasten the rails to the the rack. Then two bolts per rail to fasten the UPS rack ears to the front of the rail. Four of the bolts must be flat head and countersunk to fasten the front of the rail to the rack and allow the rack ears to stay flush. The rest can be any style head.

All bolts should be at least 20mm long.

If this sounds like AI instructions, it's because I've installed a bunch of these rails and UPS, and also used the rails without having the original hardware, and instructed other people at my work how to do it.

Gotcha. So I need another four bolts (at least 20mm long) to secure the UPS rack ears to the front of the rail.

Tbh, I do have the 8 bolts and conical washers for this rail kit as I got this kit brand new. What I don't have are the bolts/washers that screw the UPS rack ears to the front of the rail.

Also, I have a rail kit for a Supermicro CSE-846 chassis that did not include any screws but looks like it has the same size threads as the APC 0M-756H rails because when I tried using the APC bolts they threaded just fine to the screw holes on the Supermicro rails. Do you also have any experience on the Supermicro rail kit?

In summary:

* APC rail to rack screws - 4 x 10-32/M5 bolts front, 4 x 10-32/M5 bolts back (20mm length) -> I already have these installed
* APC UPS rack ears to rail - 4 x 10-32/M5 bolts front (20mm length) -> these I have to source
* SuperMicro rail to rack screws - 4 x 10-32/M5 bolts front, 4 x 10-32/M5 bolts back (20mm length) -> the seller of the APC rail kit will give me extra of those bolt and conical washers so I'll also have 8 of these soon.
* SuperMicro rack ears to rail - 2 x 10-32/M5 bolts front (1 each rail) -> these I have to source and I don't know what length I need. Any idea?

 

[nabsltd]

Tbh, I do have the 8 bolts and conical washers for this rail kit as I got this kit brand new. What I don't have are the bolts/washers that screw the UPS rack ears to the front of the rail.

Use the bolts that came with the rails to connect the rails to the rack, and then use any style M5 bolts to keep the UPS from sliding forward. You can use just one on each rack ear if you want.

For all your small metric bolt needs: $18.99 $7.99

 

[kevindd992002]

Use the bolts that came with the rails to connect the rails to the rack, and then use any style M5 bolts to keep the UPS from sliding forward. You can use just one on each rack ear if you want.

For all your small metric bolt needs: $18.99 $7.99

Right. But what length of M5 bolts should I need to secure the UPS and the CSE-846 chassis to the rails? I feel 20mm is too short.

 

[Greg_E]

In general, in the USA they are #10-32 and often shorter is better. All you need is a few threads sticking out the back side of the rack+shelf assembly. More threads sticking out the back does nothing for you but take longer to screw into place. Cadillac of rack screws https://www.legrandav.com/products/accessories/hardware_and_fasteners/rack_screws/hp