First, welcome to our Forum.....
NO, you should have 12+ volts to the S/G at the point the power is applied.
You have an electrical loss issue. It is either on the positive side or the negative (grounding) side.
Check your Battery Terminals to make sure, they are clean, polished, and tight.
Check with your DVM or VOM, and make sure that you have zero ohms resistance between the case of the S/G and the negative battery terminal. If not, clean, polish and tighten all ground connections.
Check you positive battery cables and examine for cuts, abrasions, discolored insulation, frayed ends, etc. If the cables look good, then clean, polish and tighten all connection points. If not, replace the cables and it certainly wouldn't hurt to up the size (AWG) of the battery cable(s).
Lastly, this may take an extra set of hands, but check the voltage at the Starter Solenoid. While turning the S/G over, the voltage should be the same on the input terminal (from battery) to the output terminal (to S/G). If not, replace the Starter Solenoid.
Let us know what you find.