SPDT Snon-rotarySG

Hello Everyone
I have been thinking of a possible subsitute to a SRSG that would not
require a sync motor.  I would like to know if there are any flaws that I
have missed.

My idea is to have a metal armature, which would be one side of the gap,
that vibrates between two contacts which are shorted together, which make
the other side of the gap.  The armature is weighted so its natural
frequency is a multiple of 60(or 50)hz.  A magnet would be placed near
the bottom(or just a lump of ferrous material) with a coil next to it. 
The coil would be powered by the mains supply and draw only a few watts. 
If all goes as it is supposed, the coil would pump the armature until it
is in full swing, where it would get close to one contact, cause the gap
to fire and then swing towards the other contact causing the gap to fire
again.  The firing of the gap would be locked in sync just like a
rotating gap.  Technically I could do it with only one contact but having
two gives 50% duty cycle to let them cool down.  Or more than two
contacts could be used by placing the additionals above the armature. 
Would I be able to adjust the natural frequency of the armature close
enough to the 60hz multiple?  Or is it not worth the hassle and I should
just go to the junk store and spend $10 on a fist sized 1800 rpm already
sync-ed motor?