Does the hole used for many Shure and Sennheiser rack systems have a name. It's the one which is just a small1/2" diameter hole with on side squared off/flat. For use with the included BNCpass throughpanel mount connectors for antennas.
I've found "D" style mounts terms and Keystone but can't find what that hole may be called. I'd like to get a 1u rack panel made with 6 of them in it.
Depending on how hard the panel will be used, a round, half inch hole works fine for a BNCpanel mountcoupler. The D hole is only needed where a wrench tightened nut and lock washer isn't sturdy enough. Greenlee makes both round and D punches in that size.
These types of holes are called flatted round and come in many diameters in electronics to suit connectors and switches that need an element of anti rotation as part of the their assembly. As others have said a lock washer may be sufficient when a plain hole is drilled in the panel, especially for a connector that isn't frequently disconnected and reconnected. Should you wish to buy a punch for one you better be sitting down when you shop.
Assuming your measurement of a 1/2" hole is correct this would be the Greenlee punch for your needs:
Since Daniel answered your question on the flatted round I wanted to offer more information on a D solution:
To punch holes for D type panel connectors I use a 15/16" standard round hole punch Greenlee #GL730BB, wrench operated ($78)
Canare makes a 50 ohm D type shell bulkhead here, they are about $6 each or so - in my experience they work well and look nice, and because they are recessed the BNC stays protected and they also work to connect 1/2 wave and 1/4 wave antennas. However, sometimes I find that my fingers are too big to unscrew the collar on the BNC from the recessed D shell connectors, it just takes some patience if you are doing a lot of patching.
