Originally Posted by
sloar
almost looks like the back part of a chainring bolt, maybe try a chainring wrench
too small for that tool.
I would flip the bolt just for grins
originally the bolt faced the drive side
lube the bolt not the slotted nut.
with the bolt away from the bike thread the bolt and nut together and check for fair threading and bolt straightness.
I am not fond of this design.
I would consider a longer bolt, bushing and a nylock nut that you can get some purchase on.