47-55.1 Drum screw

[leegreen]

Call up a fastener supplier and ask for a 'self locking Place bolt' of the required thread and length, most will be able to help. But you may have to buy a box going that route. Fastenall would be a good bet, I think they exist in US as well as Canada

If you don't care about the non matching head, just use some thread locker on the regular bolt.
If you care about restoration points you may need to find a similar axle to liberate a bolt from. These bolts only came into use in the mid 50s and there are a few variations. Finding a new match may be tricky