field sharpening knives axes machetes: problem

Great mangled quote from Foxhunter on the 'Other' forum.

The longer it holds an edge, the longer it holds the bluntness

Or, the easier it is to sharpen, the easier it will lose the hair popping sharpness.

I know this isnt 100% accurate, but for a beginner sharpening, its good not too have too high an expectation of sharpness retention.

I have a Tramontina that I convexed with a stone and mouse pad + Wet&Dry it gets very sharp, then loses the shaving ability quickly, but its still sharp enough to do what it was designed for and still sharp to the touch.
 
The first thing to check for is a burr- that is often the culprit when a blade seems sharp at first but degrades very quickly.

If you can rule that out, then here's another idea. If you're using very fine stones excessively, especially if you're using a lot of pressure, you may be doing something more like burnishing or "steeling" the edge rather than honing it. (is that ceramic/clay piece glazed?) The microscopic bit of steel at the very edge will get bent back and forth so much that it actually gets work hardened and weakened. I think I remember Cliffy exploring this & saying that a lot of steeling would make the edge of a decent knife behave more like mild steel in this weakened state. I know he actually changed his sharpening practices by cutting the edge directly into the stone with the first few passes to totally remove the weak steel from the edge.
 
I think you are doing well if you can get your machete to shave. Just remember, a shaving sharp edge would be very thin. Subjecting it to the forces typically associated with chopping coconuts (and the board) will quickly degrade such a fine edge. Just make sure you remove any burr or wire edge when you sharpen it. Also, machetes are usually heat-treated to a lower HRC so that it can stand up to the typical rigors of chopping without cracking or shattering.

I would say that if your machete is sharp enough to perform the tasks you would typically use it for easily, you are on the right track.
 
yea possum, my girlfriend mentioned the possibility of a bur to me last time and i tried to remedy this by making sure to use the same amount of passes on each side of the blade. i know i need to add a leather belt to my tool kit for stropping... that is the removal of the wire edge which is the final worked down bur, correct? and the method to avoid a bur is to use the same number of passes on each side and be sure to alternate sides evenly? but how do i know if im using my fine/ultra fine stones excessively? where is the line drawn between a nicely polished edge and a "steeled" one to someone who isnt extremely experienced? i forgot how many passes on the fine stone i did but i did 25 on one side 25 on the other then 25 alternating on the ultrafione stone. it is ok sharp i guess its working for my purposes but obviously i want max performance/efficiency i got my axes sharp but i dont think i got them shaving sharp or ever cared to. why would you guys care to? youre saying an edge that fine would always be destroyed upon impact especially slamming an axe head into bark and trunk... why bother? i dont understand
 
Just because you used the same number of strokes on the edge doesn't mean there isn't a burr. There are too many variables like the exact sharpening angle, pressure, bevel being thicker on one side, ect. It sounds to me like you have a burr problem, there is a sticky at the top of the maintenance forum that tells of microbeveling. Microbeveling is your friend, if you are trying to get a razor edge on a single bevel only, it can be very challenging and you are probably working much harder than you have to. Microbevels also help get rid of stubborn burrs which tend to flop around on softer steels such as the machete.

To apply a microbevel, sharpen as usual except just get a good working edge with a medium/fine stone, don't worry about getting the edge perfect at the moment and don't waste your time polishing. After you get a nice thin primary bevel, increase the angle at which you sharpen several degrees, in other words lift the blade spine up more for a more obtuse edge angle, use your fine stone for this (the Spyderco might be a little too fine if you have a large burr, I would stick to the Arkansas or white sharpmaker rod for this task) and give each side a couple of strokes using very light pressure, you can check to see if you have a burr left by seeing how the edge bights into your thumbnail or other hard object, if it bights harder on one side than the other, you have a burr on that side though it will probably be very small. You can make another very light pass on that side, or you can strop it true with a piece of leather.

I have been freehand sharpening for years and a soft or hard Arkansas stone with a microbevel gets all my knives hair popping sharp,and they stay that way for quite a while. Don't let people tell you natural stones aren't good for sharpening, I have lots of sharpening equipment including jigs, diamond stones, ceramics, and other devices and prefer my Arkansas stones dry any day. They have great feedback and leave an awesome edge in capable hands. Sounds like you are on the right track, just give my technique a shot and let us know if it helps. You are also more than welcome to shoot me an e-mail if you want to ask me any questions directly. Good luck and keep asking questions, this place is a wealth of information.
 
I don't think the bevel angle used or the quality of the axes and machete has been discussed. Maybe I missed it. A convex edge comes to mind as indicated here IMO and was discussed briefly.

I sharpen my axes and machetes on a belt grinder working down to fine micron grits and finish by power stropping with loaded leather belts to mirror edge. I use a pretty steep (abuse) angle for edge retention because of the abuse I am going to give them and how soft the metal is. I am guessing the angle of the edge is around 60 degrees included on the machete and a little less on the axe because I am more careful with it as to what I cut (only wood) but both are convex. If I had a racing axe I would sharpen it a lot differently. Note that the Bark River modified Ontario Knife machete is a convex grind.

Both a steeper angle and convexing help with edge retention because the edge is stronger with more metal behind the edge. Especially when working with very soft steel. They still shave though. I might not be a close shave but they pop hairs none the less. I have a very soft cheep no name machete that I sharpen to probably (I am guessing) about 70 or close to 80 degrees included to get it reasonable edge retention. Again being convex it seems more acute then that, is very sharp and cuts well. I use that one for chopping into the ground sometimes. How acute an angle you can get away with and still hold and edge depends on the steel, hardness, and use.

You could sharpen a convex edge on a mouse pad with sandpaper, freehand with stones, the sanding pads mentioned earlier or a combination of the above. If you are set on V grinds maybe a more obtuse angle is in order and will give you what you are looking for.
 
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