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Post by Deleted on Jul 30, 2008 20:45:29 GMT
Edgewise, is a 25 per side/50 total degree secondary bevel strong enough for a sword used in un armored combat (well, bottles with the occasional miss into a piece of wood or plastic)? Also, what is the average angle for historical medieval swords (the ones that had secondary bevels) and what is the average angle on presharpened (and on professionally sharpened) modern production swords? Just curious as I've never really bought a presharpened sword and I keep reading that 30-35 is good but when I did a machete at that angle (I practice sharpening on them) it looked VERY steep. I think the accusharp is 25/50 but I'm using a file and stones (I have a 25 and 35 degree blocks that I use to check my stones).
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Post by hotspur on Jul 31, 2008 1:04:54 GMT
Ideally, forget all about measuring angles and consider the crossection of the blade you are dealing with. If you are sharpening a blunt to sharp, you are really doing work that the person grinding the blade usually did not take into account. This usually means you will end up with a secondary bevel. One can do this as crudely, or cleanly as one wants to. The object of the exercise is to sharpen at as shallow an angle to an existing grind as possible. On a blunt, if done with a file or metal hogger this usually means creating a secondary bevel and then drawing that back up the grind to a shallower angle, again with files or stones (or paper, or belts on a grinder). You can approah it the other way with any of the tools other than the preset angle metal hogger. That by working the grind behind the edge first. Even free hand with stones, by blending, you will end up with a somwhat convex (or appleseed, or Moran, or simply convex) cutting edge.
Certain types of medieval swords did actually have significant secondary grinds to begin with. These are not small secondary bevels but more like the saber grind on some knife blades. This is a good mental picture as well. if you consider a saber/re that has a wide fuller, there is are then bevels that meets to form the edge. This, not unlike a hollow ground knife blade with a buttressed secondary edge. To effiiciently sharpen these from blunt, you are wanting to work those bevels until they meet, not impose an obtuse secondary bevel at the edge margin of those bevels. Just as with a convex Japanese (or other) blade, the object of the exercise is to work the entire main grind.
In the end, whether convex, flat or hollow ground, maintaining an edge is easier than creating one. At that juncture, they all consist of two grinds meeting to form the cutting edge itself. Any increase in that included angle is counter to the way the blade was initially ground and will (if continued over a period of time) more quickly use up a blade on say, a pocket knife. That is really the beauty of convex grinds, in that working the whole grind crossection removes a minimal amount of blade width while maintaining the grind geometry. The same philosophy can be appreciated with any set angle in sharpening. As the blade width decreases, it thickens. this is where thinning the main grind, or blending that secondary bevel becomes quite useful down the road.
Honest, I'm trying toi keep paragraph breaks in mind.
I have not once in my life (I'm no youngin') really measured any angles when maintaining a sharp edge. I have considered and guesstimated them. I have even used preset angle tools at times.
Durabilty shouldn't be an issue unless you feel the need to do a lot of lumberjacking and metalwork with your sword. yes, edges wear. Some more than others but if you sharpened something from blunt, maintaining an edge is going to be pretty simple.
Good Luck. There are lots of ways to get it done and certainly more than one philosophy about how to do it, how sharp is sharp and many other sharpening preferences/habits.
I'll end as I began, pretty much throw thoughts about specific angles out the window and approach any blade on its own characteristics.
Cheers
Hotspur; I've got some stones around that I haven't seen, let alone used in years
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Post by Deleted on Jul 31, 2008 5:18:23 GMT
The sword was already sharpened (by myself) but I didn't know if it would be best to continue at the angle I am already at (bout 35) or do something different (it was my first sword and was sadly subjected to a variety of things including an accusharp) once it finally gets dull . The part that confuses me about the convex grinds are when the sword is hollow ground. It basically would go from concave to convex but what way to do this is what confuses me the most. I guess what I should do is follow the slope as it was and continue to both sides meet. My next purchase probably will be sharpened but I guess I can look at the primary and basically let it slope from there once it needs sharpening or if it doesn't cut(I test by stabbing the length of each side through paper using some downward motion. my sword won't grab paper, but it will pierce and cut it's way out without ripping the paper) . Luckily my sword is still sharp enough now. I guess this method will also make the sword look better as it will refinish the whole sword in whatever grit I use. Sorry if I got anything mixed up here this is all new to me (different than knives, machetes and axes) and I thank you for your help.
Rob
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