_Now_ he tells me.

Well this project is a 'mule' a test box of a line array so I am
using up things I have to do the build.

And yes local hardware store has the real kind of t-nuts.

On looking more closely at what was happening, when using 2 of the
hurricane nuts when one would tighten down it would draw the
second one out. So bolting into one of these worked ok for this
job.

The treatment is not what I wanted though. I wanted use up those
hurricane nuts and dump the rest.