Click,Click,Click!

Alright everyone, here is what I have done in the past few days. Jacked up front end, tapped starter with hammer, did not help. Removed battery and had it checked at two auto parts stores (Advance and Napa) and results were the same. Removed starter and checked operation. Worked as it should. Reinstalled and tried to check voltage to starter under load. Unable to because as soon as ignition is turned to start position everything went dead. I then proceeded on with other checks. I checked ground wires from battery to engine block, block to frame, block to firewall, with multimeter for resistance, wire tightness in eyelets, cleaned contact points. Checked for tightness of cables in clamps, resistance of battery cables, positive and negative. Retested as per step 4 & 6 (67Dart273) voltage .4. Attached meter to red wire on starter and to ground. Jumped starter relay, voltage 11.5. Voltage at small terminal of starter 12. Checked voltage at starter relay (12.5). Recleaned battery terminals and eyelets of battery cables. Checked wires under dash, at firewall block, and at ignition switch. I could not think of anything else to check. Anyhow, after doing all these checks, cleaning, and tightening I turned the ignition switch to start and the engine started!! Can not tell you why, but something following all the steps suggested I can now say that my Dart runs again.
Thanks to all your help, without it I think I would still be scratching my head and going down dead ends.
If anyone has any idea as to why my engine now starts, let me know.