The newer 633 axle shafts are much softer than the older ones. A file will nick anywhere on the new shafts. The 4 pinions are pretty hard all the way down, file just skates off.
You can see there’s an undercut at the end of the hex, so they didn’t have to cut it all the way to the shoulder. This turned down section is where the shaft broke.
Older one. I’m designing plate lockers for both 4 and 6 pinions as well, and a locker to use splined 6 pinion GT axles in the older 4 pinion.
I'd be interested in your plate locker. I have an older SS16 I don't know what I'm doing with yet, but for sure it will get locked.
You will have to pull it apart and see if it’s a 4 or 6 pinion. I’d think 6 being on a SS16 but who knows. Feel free to PM me about it.
Set a piece of 5/8” 1045 up in the spindexer in the mill
Gave it a super heavy press fit. About .002” worth. Had to beat it in with a 5lb hammer.
Once that was done i peened the end of the shaft over so the gear doesnt come off. The original had this done a bit more nicely but I’m alright with this.