Irregular rack thickness???

[Rich Nelson]

Paul Schreiber wrote:
> 
> While looking at the deep mechanicals of the MOTM front panels, I decided to measure the thicknesses of
> the front panels of the stuff in my rack. It's important to note that there is a 1U space between each unit,
> 
> Much to my surprise, no two matched! Here's what I measured:
> 
> DP/4: 0.125"
> Mixer: 0.100"
> D*****L sound module: 0.070" <figures!>
> Midi interface: 0.092"
> 


The dimensional details for rack panels are specified in EIA Standard
SE-102, and MIL-STD-189.

Thicknesses of 1/8, 3/16, 1/4, and 5/16 (!), are standard (?).  And to
meet spec they must be fabbed
from aluminum.  Mounting slots may be open or closed, with a width of
1/4 inch, extending from a circle
with radius 1/8 inch, with the center of the circle located 3/8 from the
edge of the panel... the
horizontal mounting holes are spaced 18-5/16 center-center. The
horizontal space between the panel mounting
strips is 17-3/4 inches to allow standard 17 inch chassis.

Mil specs call for mounting using #10-32 oval head screws and cup
washers.  Commercial specs call for
#12-24 screws... and I have seen mounting rails threaded for #12!

Aren't standards wonderful!

rich
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