Pretty sure this is how I did it until I got the larger end on the Park tool. Any suitably sized washers will do the same job too.Octalink crank remover has a "top hat" that pops into the axle end for the tool to bear against.
Iirc a well placed 5pence piece does the same job.
What stops the bolt from pushing outI made a 'tool' years ago which was basically a spare bolt with a length of threaded rod hammered into it, screwed on from the opposite side so the rod was flush with the end of the spindle/axle for my tool to push against.
The 'tool' being the green part.
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