Knives are side weapons, MJJ
Yes, a mace or a hammer would get force through plate. Depending on where, and with how much power behind it, significantly so. Not arguing this, no one would ever argue it. BUT
BUT
They are TERRIBLE weapons, for fighting someone who also carries a weapon, that is not the same silly type of weapon (either because you're both peasants, or carpenters using work tools, or it's a fight for sport). Especially against someone with a shield.
You need to be positioned at a very peculiar range to get in a good hit, not too far, not too close. And against someone with a shield you have a very limited angle to come from.
You need to make too big of a movement to get at someone with enough power to actually cause some hurt through the plate. And that's assuming you get any openings at all. Your enormous predictability makes you easy to parry and block. Your opponent has almost as much control over your movements as you do. You'll just end up doing the same in your face wrestling dance that the sword guy must. Just with a weapon much less cut out for it.
And even if you get your biggest, meanest warhammer or longmace, just no. More power, but still silly, more unwieldy, and now you've given up the option of a shield.
Now I'll wait for someone inevitably showing me how I'm an idiot by showing me the amazing arts of fighting with maces and hammers that I've heard of.
