Fort Frances, ON
If you are sure it uses 12-24 then no way will 10-32 work. They are not anywhere close to be interchangeable.
I have only seen 12-24 screws ship with some gear but have yet to actually have a rack that can take them. A 12-24 is a much coarser thread and would not even start in a 10-32 hole so if you can run them in more than a turn, then you have some QC issues. I would get a 12-24 tap and run it through the holes to make sure the problem isn't the holes.
Strange as it seems, no amount of learning can cure stupidity, and formal education positively fortifies it. -- Stephen Vizinczey