So here’s a lowdown on how to sharpen a machete, or any knife in general for that matter, although you might have to adjust the techniques a bit if you’re dealing with a very fine kitchen knife instead of an all-around workhorse such as a machete.
What you want to do is leave an edge with an angle of about 15º, 7º on each side, but if you do that straight away without taking out more metal inwards from the edge, you will loose the edge very quickly, and will have to file away a lot of metal each time you want to sharpen the blade, so it’s best to take away some of the “body” of the blade so that you leave only a small amount of metal at the edge, preferably in a “v” shape with two concave sides (curving inwards) so that you are removing the least possible amount of metal afterwards with the file. This is quite involved so the easiest way to do it when you have power tools in the house is with a grinder. You have to be careful to move it quickly over the blade or you risk heating certain spots up too much, which would take the temper (hardness) out of the metal, which is irreversible once done and leaves you with weak spots in the blade. It’s also important not to grind the edge of the blade but only the metal inside, because the grinder is too harsh and would just eat away at the edge, burning it and creating a “feather”, which means shards of metal on the edge, which to the touch and when doing a test cut make it seem like the blade is sharp, but really these shards just break off and the blade becomes dull very quickly, so it’s not a good thing. Keep away from the edge with the grinder and do that finer work manually with the file. 🙂
John removing the with the grinder
if you look closely you may see a thin black line close to the edge, where the grinder has not been passed to preserve the edge
the final touches, removing kinks and “feather” on the edge
testing the blade for sharpness… ouch!
the machete family. There’s the rula, which is long and thin so that you can get it to move more quickly and is used mostly for weed wacking, the machete per se, which has a broader blade and is for general use, and the puya (at least in Panama), which has the broadest blade and is used to chop down trees. There’s another one missing here that was used a lot in Costa Rica, and which was what they called machete over there, all the rest being cuchillos (knives); this machete had a very broad blade that was bent sideways at the base to make it easier to use for half-digging half-scraping of weeds in garden beds. I’ve also included an extra item that’s not part of the family, just to keep you on your toes! 🙂