Wrong Spencer...machetes are commonly made of medium(normally factory made machetes are 1055; i happen to have 1095 one) carbon steel. They are designed to be as much resistant to chipping as possible and can withstand most harm without breaking(they will more likely bend than break). And yes machetes need a lot sharpening since 1055(or lower) carbon steel dull pretty easy, so make sure you have a sharpening stone on you if you're using machete(they don't need pretty more "maintenance"; 2-5 minutes of sharpening and they are as sharp as ever). Machete is definately an optimal choice since it's usually cheap(unlike nihonto's) and have broad cutting edge.
if your pulling the dull card, katanas dull too, and if its a traditional made one, you need a professional sharpener to resharpen it, i love katanas, but machetes are way more functional in zombie survival
There's a new method of hardening the sharp edge of a blade, that should be able to be used on swords, machetes, or knives. The method hardens the sharp edge but leaves the back end softer to prevent the blade from being too brittle to use in battle.
My machete was military-issue, so its carbon-content is FREAKY high. It'd take, like, a semi-truck to even bend it (slight exaggeration). I've even been sharpening it since December, and it's still not as sharp as it could be.
And as far as katanas go, authentic hand crafted ones should be sharper than a biotch, but also put a large hole in your retirement fund. They don't actually require sharpening, though, as far as I've learned, just a polishing.
Still, katanas are better than any other sword, next to the Gladius, but still yield to the machete's ultimate practicality.
Crowbar hands down! The crowbar is a puncture weapon, a bludgeoning weapon, and it is useful for breaking down abandoned barricades. Most people think think a machete or sword. Machetes are just to flimsy they are designed to take out thin vegetation. Edged weapons in general are not as useful as you'd think. Zombies don't have vital organs other than their head. The general use for a sword is to deliver a grievous wound to a vital organ or cause sheer damage or blood loss, zombies are unaffected by either. Decapitation would be the only practical way of stopping a zombie with a sword, but opportunity that in it self isn't practical, heads are a little more firmly attached to bodies than Hollywood would have you believe.