I didn't explain myself very clearly in my last post...sorry.
But I'm sure this is just a case of the 3 parts (2 x nuts and 1 x washer) being assembled in the wrong order. If you put a nut on first, then washer and finally last nut, everything will go further onto the crankshaft thread. I do not have the spring retaining cup to be 100% sure but if you look at these two photos, you will see that it is the washer that is preventing full use of the thread. In addition, if the washer is between the nuts, I assume you are mean to bent the many tabs in both directions to lock both nuts:
'28 Model B (project), '30 Model F, '31 SF31, '35 4F, '38 VB (project), '39 4G (project), '46 VH, '48 KG