"
In addition
to grounding my dust collector vacuum lines I was thinking that I would
go
ahead and run a ground wire on each unit to the cold water pipe for
added
protection.

Don't do this. You could be creating a dangerous situation. In many
homes the cold water pipe is not a suitable ground and some errors could
cause them to go live. Unlikely but possible. Just use the ground
provided
by the circuit.

I agree with the Irish tiger. Don't.
If bonding to cold water or other services is required my understanding also
is that it is done once at the main service entrance panel. Not random
connections to piping that may or may not be contiguous through the house
plumbing back to a cold water supply system that itself may or may not be a
good electrical ground.
AIUI this is not the same thing as a requirements, in some countries, to
electrically 'bond' together certain metal pipes etc. within say a bathroom
where there are electrical appliances, to avoid voltage differences, in the
event of a fault within that area.