Cable repair ?

Hi all,

     I am trying to gain some extra length out of a factory Clutch  
cable.  This is the kind that has a solid cable (vs multistranded)  I  
have to keep the knob which is important.  The cable was crimped  
inside a support that is part of the knob.  anyone done this?  My  
first thought is soldering or welding or removing the knob and  
fitting it to a lawnmower cable..

Lester