• My first idea was to just push my hand drill sideways in the slot. But i guess I could drill it out too.

    Sorry to be the one always replying :)
    Drill bits only have cutting faces on the end for drilling downwards. You'd need an end mill bit for cutting along like that. I'd suggest a dremel type rotary tool if you have one or a small file

  • Or even hack saw the slot all the way out — I can't see that compromising whats asked of the strength, not to mention it's quite common on front rack fixtures.

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