I had the same problem on a set of maxy cross's
I took it to a company I know who did broaching (cutting square holes) their adivce......................shim it
Becuase of the age of the alloy + its forged alloy + the cost of broaching it would be
You can buy shim steel but to be honest........I had "coke can" shims in em for about 6-8 months and with my 19 stone bouncing on them the were still nice and tight when I sold em