Dimensions of Stepped Attenuators, Selector Switches
and Installation / Mounting Data
Current stepped attenuator and selector switch printed circuit board designs: 

Goldpoint 24-position stepped attenuators have 15 degree switching angles
so knob positions point 15 degrees away from their adjacent position(s).
Goldpoint selector switches have 30 degree switching angles
so their knob positions always point 30 degrees away from each other.
-How To Install 47-Position Goldpoint Stepped Attenuators:
47-Position Goldpoint stepped attenuators and selector switches can use the "Double-D" panel cutout to the left.

However, if you choose to mount it simply with a  0.401" (10.2mm) round hole, use this anti-rotation method:

1) Place a lock-washer on the threaded bushing
before sliding it into front panel hole

2) Install the
flat washer and hex nut on the outside of the front panel. 

-How To Install 24-Position Goldpoint Stepped Attenuators and Selector Switches:
_______Very Important! The most common error made when installing one of these units is to fail to: 
          1) Use a second hex nut inside the mounting panel - as shown in Mounting Method #1.
______2) Cut or file a channel (keyway in the panel) for the key to fit into - as shown in Mounting Method #2
______3) File off the protruding key on the switch itself - as shown in Mounting Method #3.
Mounting Method 1: If the panel you are mounting to is thin: up to 0.70", (1/16"), (1.5 mm), you can mount the unit using two hex nuts and a flat washer. This is the preferred and easiest mounting method.
Important: Never allow the locking key to touch the inner hex nut - doing so could warp and damage the unit.

Mounting Method 2: If the panel is thicker than .070", mount the unit with only one hex nut and a flat washer. 
Make a notch in the mounting hole - as shown at left: 
"Mounting Hole with Keyway".
Important:Never allow the locking key to touch the inside of the mounting panel - doing so could warp and damage the unit.
Mounting Method 3: File off the protruding locking key - whether the mounting panel is thin or thick. Then use only one hex nut to secure the unit to the panel - as shown at left. While filing, cover the rest of the unit with plastic wrap or other suitable material to ensure the filings do not get into the switch contacts.

Complete Mounting Data in Acrobat PDF file