[Milsurplus] Setting the BC-342 dial, I found a way (undocumented in manual)

[Cletus W Whitaker]

de WB2CPN South Central Pennsylvania  2004.05.20

Looks like you have a shaft that not tightened down enough
to keep its gear from turning.  When you go to end of the
stop it blocks the gears, and the vernier shouldn't turn
anything any further.  Something is loose enough to give
a little bit.  In your case it may not be worth looking
for if you're happy with the way it's working now.
             73  Clete