I am in the process of finishing up a display case for my son. The case
will have glass on the front and sides and have a mirrored back. Because of
the design the glass is installed from the outside of the case. The rabbets
that receive the glass are to receive glass that is 3/32" thick and a 1/4"
radius quarter round.
Arriving at the glass store that I normally purchase from there is a new
girl working behind the counter. She apparently has been there long enough
to know the jargon but is clueless when it comes to the actual thickness of
glass.
When she asked what thickness of glass I wanted, I indicated 3/32". Her
response was, we only sell 1/16" and 1/8" thin glass for cabinet use. I
knew 1/8" was too thick and 1/16" breaks too easily. She pulls out two
samples of the glass and I look at their thicknesses and I tell her I want
the 3/32" piece. She says again that the samples are 1/16" and 1/8" thick.
I put the edges of the two pieces side by side and told her that one was
clearly not double the thickness of the other. Yes, the thinner one is much
closer to 3/32". Grabbing four of her 1/16" thick samples and putting into
a stack and three of her 1/8" samples and placing those in a stack beside
the other stack they are of equal height. I looked at her and said, four
1/16" thick pieces of glass stacked should not be the same thickness of
three 1/8" thick pieces of glass stacked together.
She looked at me like I was crazy.

When I got home the glass measured out with the dial caliper at 3/32" thick.

I do believe that she realized that the 1/8" thick piece was not double the
thickness of what she was calling 1/16". I suppose that she did not
understand that 1/16" is half of 1/8" thick. Geez.

Was this just me being like a noob to wood working and being confused with
why a 2 x 4 is not two inches thick? In the past the seasoned employees
behind the counter at the glass company knew what I wanted when I said
3/32" thick.