Crank arm loose (squared taper). Can it be fixed?

Question

My problem is that my squared taper crank arm keeps on coming loose no matter how hard I tighten the bolt - it also starts creaking.
Here’s a video of the problem
https://giphy.com/gifs/RlN0wNSZsWluF5izKz
I’m thinking replacing the crank arm would do it since it seems to have become larger than the axle. But I’m curious: can this be fixed somehow?
Edit: I’m thinking the whobbliness is normal since the bolt is suppose to tighten it against the axle. But the problem is that the axle has come all the way through the space for the arm, making it impossible for the nut to squeeze it against the axle.
Here you can see the axle coming all the way through the arm. Is this normal? Shouldn’t it stay inside so the nut can squeeze it against the axle?

Ideas if this can be fixed? I’m thinking that a new axle could also have the same issue
Edit 2: I’m thinking perhaps a washer that is as big as the crank hole walls could push towards the axle?

Argenti Apparatus · Accepted Answer

This question about loose crank arms has been asked and answered several times before on this site, but yours is the worst I've ever seen I think.
Unfortunately your crank arm is ruined. If the alloy crank gets loose and is ridden on the hard steel spindle wallows out the relatively soft alloy. It does not matter how tight the retaining bolt is done up the deformed crank arm will continue to come loose.
Replacement crank arm (or both crank arms) is the only solution. The bottom bracket and spindle are probably fine (unless the bearings are worn out).

BetterSense · Answer

If the bolt is bottoming out on the spindle, then tightening the bolt won't do anything. As you pointed out, you could potentially insert the correct spacer, if you could find one, into the crank to allow the bolt to tighten once again. It would be a rather special spacer though.
If you are truly without scruples (i.e. if it's a junk bike and you need to either fix it or scrap it) you could grind off a couple millimeters of the crank spindle, which would do the same thing.
If you rode the bike with the crank arm loose for any length of time, the crank arm is probably ruined and you will need another crank arm anyway. It's probably best to buy or scrounge a new left crank arm.

Crank arm loose (squared taper). Can it be fixed?

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