I have a situation where I needed a 5/16" recessed nut threaded knob.
However, at the local hardware, only a knob with a 3/8" recessed nut was
available. Since I didn't have time to order and wait, I am trying one
of two things and I would appreciate any commentary. I bought some
plain, hex 5/16" nuts. Since the recessed nut in the knob actually has
part of its metal surface at the same level as the knob, I decided to
place a drop of threadlocker on there, carefully drop the 5/16" nut onto
that area, and then compress both pieces together as tightly as I could
with a clamp. After I first did this a few hours ago, I let the clamp
in place for about 20 mins, then removed it. At first, I thought the
bonded nut was going to hold, but as soon as I applied enough pressure
with my hand, it came off. Since there's no threads actually grabbing
and this is essentially a nut up against a nut (but compressed with a
clamp), I don't know if this is going to ever bond well with the
threadlocker.

The other option I'm considering is to simply drill out the reverse side
of the knob a bit, drop the 5/16" nut in there, and glue in place with
something like two part JB Weld.

There's going to be a lot of pressure on the knob as it is turned to
hold something in place, so not sure which option above would be best.
No time to order and wait for the 5/16" knobs.

Thanks for your help.

JBL