TR2/3/3A Another starter problem

Having found the correct(?) starter I connected the cable: using a four inch spanner I tightened the nut steadily and was surprised that it did not come to a stop. Instead the terminal bolt seemed to be getting linger, so it must be pulling out. If it were rotating with the nut it should go in not out unless it has a "left hand" thread at the other end. Yes? ( I cannot see what it does when I turn the nut, bad eyes and bad visibility.) I have not found a diagram of how this end is put together, and I am not sure I should just wade in ( usual style) and take it apart and attempt to fix. I have the old "bomb" starter that I could cannibalize if necesary.
Any and all suggestions welcome, and i will try to photograph it later today.

The stud is soldered to a rather large wire, actually more of a "strap" inside the motor housing. The inside of the stud has a shoulder, on which is a fiber insulating washer, then a nylon insulating bushing where the stud passes through the housing, and finally another fiber insulating washer under the outer brass nut.

For the stud to start pulling out, the inner insulating washer is likely broken down. It will be difficult to tell if it is shorted or not, as the internal coils are so large that an ohm meter will always show 0 or near 0, even on a good starter. Since the stud is located by only fiber washers, the power cable should never be cinched down too terribly hard.

If I am reading this correct, that brass stud should be double nutted with jam nuts to keep the stud in place so that does not happen. How far did it come out? if just ¼, then push it in double nut it. BUT then again that is high amperage and the correct way is to pull the starter and make sure the strap does not touch the case.
steve