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Simple rackmount hardware questions.

I've been converting a number of network sites from the use of wooden shelving to 19-inch rackmount.
I understand the rackmount post-mounting standards but didn't realize the wide variety of equipment manufacturer mounting bracket designs.
Also, I've done considerable web searches and don't find details for such seemingly mundane things.
To keep it simple enough here, I'm interested in L-brackets or "ears" that attach to the front corners of "19-inch" full-width devices: switches, routers, firewalls, etc.

Generally, the brackets are attached to the device with small flathead screws.
The simple question of "what size are those screws?" seems to be hard to determine.
Juniper Networks
I can imagine that there is variation in screw size within companies' product lines.  Is that a common situation?
What sizes?

Right now, I need a set of mounting brackets and screws for a Juniper Networks SRX340.  
Where can these be purchased?
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Philip ElderTechnical Architect - HA/Compute/Storage

As a rule all devices that are able to be mounted in a rack mount enclosure come with their ears.
Distinguished Expert 2019



My experience is, you usually cannot get the correct screws. They're usually the indent type (as not to get in the way of the sliding in the rack, and they're also short (not to touch internal electronics).

It would really be a mighty coincidence if you lost them, and got 8 exactly the same fitting screws somehow. The lottery has higher chances of winning. Please note, even the L bracket is usually unique to the device (especially the smaller devices).

Principal Software Engineer
It's been my experience that about half of rack mountable devices come with brackets.  In some cases the manufacturer considers this an option and requires another $20 to $40 for the mounting brackets, so it is well to discover the situation beforehand.  In one case the equipment manufacturer had not intended a digital VCR to be racked, and (Winsted's name deleted) wanted $100 for a pair of brackets.

Despite RETMA racks being an industry standard, so far as I know there is no standard as to where the attachment screw holes are located on equipment, nor on how thick the brackets are, nor on what kind of screws are used.  I've seen six #6 flathead and two #12 flathead and some that slot in from the bottom.

For cases where no brackets were supplied I kept a length of dimensional aluminum, right-angle, and made them myself which worked out to about 75 cents each, obviously not counting my labor which dwarfed the material cost.  Countersink the holes and use flat top screws with a countersink profile so the sides are flat.

Pro tip:  When you get equipment with brackets but won't be racking it, throw the brackets in your tech support hope chest "for later."


Thank folks!

Dr. Klahn:  You have it right.  My "hope chest" did have some and not others.  So, folks the situation is that I have a lot of "19-inch" devices with no brackets because they weren't needed in the initial installation.  And, perhaps some came without.  I am tempted to get out a drill and CSK.  Then there is the issue of the screws to be identified.

I did find cablesandkits.com and they seem pretty good for CISCO - but no others.  So that part of the solution seems in place.
They have a 30-day return policy so one is protected if the wrong gadgets show up.  So that's attractive to a fellow with a Scot's surname like me!

Full disclosure: the only thing I've found for Juniper Networks SRX340 was a pair of little "L" brackets with screws for $100+.  Right thing, wrong price in principle.  That's compared to $20 for similar items.  Of course, I could just give in - but shopping often pays off, eh?
Maybe somebody has a "hope chest" with Juniper stuff in it?

Just to be clear, I'm fine with what attaches to the *rack* and have a variety of screws for that purpose.
It's the brackets that attach to the box that I'm dealing with here.
I need to find (or build) the brackets.
I need to find the screw type and size (well, flathead of course).  It appears that Cisco uses M4 screws.  I have no idea about Juniper Networks.

I do understand that the brackets vary all over the place.....
So, the solution to that is to find a source of supply or build something.
Dr. KlahnPrincipal Software Engineer

Another thing you might consider is to dispense with the brackets, and go to slides instead.  The cheapest slide is just a piece of thin L aluminum which bolts to the side of the rack at front and rear (or halfway back if you are lucky and have racks with side brackets)  No bearings, no wheels, just a piece of L.

The great thing about these is that when something fails, there is no need to scrounge up somebody to squeeze into the back of the rack and hold up the equipment while somebody else unscrews the front, and reverse when installing the replacement.  Slide in, slide out.
Distinguished Expert 2019


That is why I use 4 post racks vs 2 post racks. You can even buy slide out trays for small equipment use cantilever shelves.


Thanks!  Good ideas.