Rudedog53,
Welcome to stovebolt.com.
There is a copper contact inside the "push button" "starter switch" (that switch is called a
a mechanical solenoid).
It makes contact with a copper "button" on top of the starter.
If either/both pieces of copper are worn down, a good contact cannot be made.
It is easy to take the push-button assembly off the starter to inspect the contacts.
Or, first see if a wood/rubber shim placed on top of the push button allows a better connection and allows the starter to crank.
If your truck has been converted to 12v, it might have
a mechanical solenoid with a side switch (which is for a lead to bypass a 12v ignition's ballast resistor).
