Eureka Clock

First section of video show the clock after being cleaned and partially rebuilt and having had the coil rewound complete with a new contact pin and 'flag' installed
the second shows the same set up after the pin had been adjusted as it was such a bad fit in the clamp
the third section was taken when trying to get the amplitude correct to run at 60 seconds/minute (which we now understand may be incorrect)
the final section shows the clock after a new return spring had been fitted and failed with the old spring replaced and adjustments to the contact pin insulation to try and get it to hold correctly in the clamp,
our suspicion is that the pin/contact is incorrect and the amplitute is therefore incorrect not giving the right amount of throw to operate, coil was correct, battery at 1.7V, good magnetic pull, lubricated correctly etc etc......
but what else is there to consider