2y ago

APC server rack with threaded holes instead of cage nuts

Just picked up an APC 48u server rack. There were no pictures of it in the post and I did not notice until I got it home and set up, that the rack rails have threaded holes instead of square cage nut holes. I can’t seem to determine the thread size and pitch, and have a thread gauge coming. Until then, does anyone know anything about this? The people I grabbed it from had used self tapping machine screws and drove them in with an impact wrench. Is this what APC had intended, or is there some $300 proprietary screw I have to buy from them?

16 comments

While I can't speak for your rack in particular, most pre threaded racks are either 10-32 or 10-24 screws.
You can buy them easily on Amazon.
I work in television, and in our equipment room we have 50 racks that are pre threaded. And we use these: [Amazon link](Penn Elcom S1032/HP/WA/100 High Point Rack Screws with Washers - Set of 100 https://a.co/d/g13kPzw)
- This is what I thought too, but both #10 threaded bolts I have are too small, one will thread, the 24 ones I believe, but you can wiggle them, enough to wiggle them out with out turning them.
  
  They're 12-24, we use these at work.

I learned this the hard way, there is a difference between a "data rack", which is the one with cage screws, and a "network rack", which comes with the threaded machine screws. I believe switches have standardized screws
- I will try and attack it from this angle. Thanks for the input!

Rack screws are pretty standard. You should be able to get a big pack for cheap from the usual online suppliers. Looks like you would want M6x16mm screws.
- I have m6 cage nuts from my last rack and they are WAY too big. An M5-0.8 will thread about half way in and then bind, making me think it’s a thread pitch issue?
  
  If they're #10 (US) screws, they'd be 4.8mm major diameter and 24 or 32 threads per inch, so something like M4.8-1.06 or M4.8-0.78. If M5-0.8 thread half way, it sounds more like 10-32.
  If you're outside the US, that might be why the previous owners resorted to the ugga-dugga. That will (probably) have wrecked those holes for either their factory pitch or whatever the owners used. You might consider getting a 5MM drill and a 6mm hand tap. You might have fair luck with 10-32 screws, depending on how hard they are to get in your country.

No idea on the screw question... but the labels are off by one screw spacing. The holes that are "close" are where the U labels should change.
- Yea, it’s only on that one bracket too, keen eye.

16 comments