[TR] wire breakage

[TERRY SMITH]

Oh.  A quick side exchange with Bill (Thanks Bill), reminded me of a question I've been meaning to ask.
TR3 switches often (always?) use bare wire ends screwed into switch contacts.  I've never had a problem with the connections breaking the wire behind the instrument panel.  But I have more or less regularly had the OverDrive switch break at the connection over time.  Simply, the bare wire must vibrate enough to eventually cause the strands to break.  
I could easily solder the ends before screwing them down, but ISTR reading here that that solution only causes the break to happen above the tinning.  
Any suggestions how to break-proof this?

Thanks again, everyone,
Terry Smith, '59 TR3A
New Hampshire