Knowing the edge angle, is it beneficial?

Neither are machetes. 1055-1095, usually 1070/1075, run in the mid-to-low 50's or high 40's. Just something to consider given that even they hold up fine to chopping use when run that low. :)
 
Mr.Wizard said:
I see. Thank you. I had not realized that was a common use case. How long and/or heavy are the knives you are describing? I've seen everything from a Buck 110 to a full-on Bowie called a hunting knife.
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Varying size, many ask for a tough edge on their camping knives. Mostly Cheap / inexpensive brands. So these peoples have all sorts of bad experience with these knives :rolleyes:. I rarely encounter real knife connoisseurs because they are all sharpening their things themselves.
 
Axes at 21 machetes at 15... :p Wait for the razor at 3 :D I been using this as general guide for a long time.

Grind-Angle-Chart-copy.jpg

Can someone provide me an explanation. As why I would want to sharpen my machete at 15 degrees. I understand why an axe could be sharpened under 35 no problem but a machete up to 15 seems... yishh.... stretching it. Normally I give the General use angle for these. and Hunting and camping knives falls in the general use also. I might be too old school but these values works perfectly for me.
 
SteelJunkee said:
Axes at 21 machetes at 15... :p Wait for the razor at 3 :D I been using this as general guide for a long time.

Grind-Angle-Chart-copy.jpg

Can someone provide me an explanation. As why I would want to sharpen my machete at 15 degrees. I understand why an axe could be sharpened under 35 no problem but a machete up to 15 seems... yishh.... stretching it. Normally I give the General use angle for these. and Hunting and camping knives falls in the general use also. I might be too old school but these values works perfectly for me.
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That's 15° per side. So 30° included angle. It's more penetrating, which actually minimizes strain on the edge because the impact force is spread along a more gradual slope. So you get better performance with less effort and the durability is just fine. NO edge damage in use, even with heavy chopping use and it works better...can you provide an explanation for why you wouldn't want the edge at an angle that's still more than strong enough for its applications and has significantly increased performance?

Meanwhile, my scythe edges are 7-9° per side and can sever thumb-thick green saplings without taking damage. Using good technique does play a role in that, though.
 
FortyTwoBlades said:
That's 15° per side. So 30° included angle. It's more penetrating, which actually minimizes strain on the edge because the impact force is spread along a more gradual slope. So you get better performance with less effort and the durability is just fine. NO edge damage in use, even with heavy chopping use and it works better...can you provide an explanation for why you wouldn't want the edge at an angle that's still more than strong enough for its applications and has significantly increased performance?

Meanwhile, my scythe edges are 7-9° per side and can sever thumb-thick green saplings without taking damage. Using good technique does play a role in that, though.
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Honestly never tried it and the tool are working good. So I never really bothered, I have absolutely no claims that thicker edges are better but it seemed logical to stay close to what the industry is using.
 
I'd suggest giving it a try, with a quality machete. It's a cheap experiment, and I think you'll find the results illuminating. If you haven't used them that thin then I think you're missing an important piece of perspective when it comes to understanding "good" performance from a machete. :)
 
Also, keener razors are more like 8°-10° per side. I've seen both lower and higher though. In my experience, edge stability is pretty dismal below 8° per side even for shaving in most cases though.
 
FortyTwoBlades said:
I'd suggest giving it a try, with a quality machete. It's a cheap experiment, and I think you'll find the results illuminating. If you haven't used them that thin then I think you're missing an important piece of perspective when it comes to understanding "good" performance from a machete. :)
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I have to sharpen my Ontario 18-1 before summer, I'm going to give it a try on that.
 
FortyTwoBlades FortyTwoBlades Are the angles you are giving mechanically exact all the way to the apex? I have skepticism for "7-9° per side" for a scythe as that is similar to a straight razor, and those (razors) still benefit from micro convexity through stropping if I am recalling scienceofsharp correctly.
 
2BSharpAgain said:
NewBe here. I have been following this forum for a while and thought y'all could help me with a question. I am wide open to your comments and opinions.

I have been sharpening for fun and money for 50+ years and consider myself a good functional sharpener. I have a reasonable working understanding of the edge angle and the trade off between sharpness and life, and the other variables that affect overall performance. I can't determine the type of metal the knife is made from, other than carbon steel vs stainless steel, and it usually does not matter when I am sharpening. The owner just wants the knife sharpened.

I have always had a problem determining either the existing or newly sharpened edge angle. Hand me a knife, ask me the edge angle, and all I can do is make an educated guess. Can I be within +- 5%?, only with luck. To help me, I purchased the CATRA Laser Knife Edge Protractor, $300+, and now I can actually see the measurement of the edge angle. I believe it helps me sharpen better and to provide consistent results.

My question is:
Does, or would, being able to accurately read the edge angle, improve your ability to sharpen?
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Not really. Factory edges are always trash. One side is 25 degrees, the other is 21 with a shaved tip at 16. I think the first step to proper results is a quality edge reprofiling to a more even and appropriate angle.

If an edge has been reprofiled and is acceptable, then I typically start low on a 1k stone and see where I land on the shoulder and dial in the angle that way. It just takes a couple strokes and then you’re narrowed in and ready to rock. Specific angle has ceased to matter to me. I just need it as low as is viably possible
 
Mr.Wizard said:
FortyTwoBlades FortyTwoBlades Are the angles you are giving mechanically exact all the way to the apex? I have skepticism for "7-9° per side" for a scythe as that is similar to a straight razor, and those (razors) still benefit from micro convexity through stropping if I am recalling scienceofsharp correctly.
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Yes, that's at the apex, and measured using a digital protractor. When freshly ground my edges are typically 15°-18° included angle. A scythe is like a straight razor for grass, though its edge is done comparatively much coarser since it's slicing rather than push-cutting. Through repeated honing they eventually thicken up due to the nature of hand-honing, but that's when you take them to the grinder again and thin 'em back out.

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When properly sharp and freshly ground, you should be able to do this:
 
Show off!!! I'll admit that the scythe I do my yards with requires a bit more effort. But it's mostly anything but grass...just whatever nature dictates. Funny how you learn quickly with a scythe what growth cuts easily and what is resistant.
 
A lot of it depends on your edge configuration and technique, too. There are definitely techniques for the difficult stuff that are comparatively advanced since you need a good sensibility of how the blade will respond, and any torque on the blade in a resistant cut can damage the edge. It was thanks to scything that the realities of the coarse vs. polished edge performance spectrum really got driven home. Early morning mowing when the dew is on the grass and it's the early-season tender growth, possibly full of dandelion and clover, a pretty polished edge and open hang work great. During midday and/or the late season or when dealing with wispy, waxy bromegrass you need a much coarser edge than you would for general purpose mowing and the edge needs to be thin and CRISP or it's just going to slip under the edge instead of being grabbed and cut. The dryer, thin, springy stalks are so much more difficult to initiate the cut on with a more polished edge, even though so much as lightly tapping the edge with your finger would cut it to the bone. I did that once in a careless moment. Probably should have gotten stitches. :p
 
I have very little flat ground, most everything is on a slope, or undulating up or down...and with the variety of growth on the front and rear yards, I'm constantly shifting and readjusting.

Plus, I don't have the fanciest gear. I have an Austrian scythe set I picked up from Lee Valley some years ago. It gets the job done but it's my first rodeo with scythes. (I was an apartment dweller until I bought this home 15 years ago.)
 
Blues said:
I have very little flat ground, most everything is on a slope, or undulating up or down...and with the variety of growth on the front and rear yards, I'm constantly shifting and readjusting.

Plus, I don't have the fanciest gear. I have an Austrian scythe set I picked up from Lee Valley some years ago. It gets the job done but it's my first rodeo with scythes. (I was an apartment dweller until I bought this home 15 years ago.)
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Austrian blades are frustratingly soft to me. You'll find in videos of users of the continental European type that many of them use a lot of speed in the stroke to compensate for the dulling that occurs almost immediately with their edges. To keep them as keen as I insist on I have to hone after ever 6 strokes or so. Of the Euro-style blades out there I find the Russian ones to take and hold an edge the best. They're almost as hard as an Austrian-made American-pattern blade, though still a touch softer, and the Austrian-made American blades are soft compared to the historical norm. I'm actually working with Arti of Russia right now to get new American pattern blades made to my own specs. They just did the first experiments with forging an American-style cross section yesterday! :)
 
I'm risking getting in over my head here and realize that the thread topic has somewhat strayed (for the better) but man, you've got guys like @bluntcut and @DeadboxHero taking steels to very high hardness with super thin grinds and low angle bevels and they can beat the hell out of them.

Have you seen @DeadboxHero 's video of what he did with a production Spyderco Manix 2 in Maxamet? Woosh! Combine that with stuff like what FortyTwoBlades FortyTwoBlades and others are doing with lower hardness steels and it all combines to tell me that my long-held thoughts on angle grinds have been mostly wrong. Or at least maybe too restrictive. I've begun laying back more of my knives and am liking it. It's a slow process for me as I don't want to screw anything up when I'm hand-sharpening material away. But yeah, I'm falling deeper into the thin is better camp. :)
 
In general, a good rule of thumb is that if you aren't occasionally doing minor damage to your edge from pushing it past its limit then you're probably not running it thin enough. Figure out how to walk up to that line without crossing it and you'll really know the true limits of the steel. When it's just a little too thin for those occasional moments when edge strain really spikes, it's still pretty easy to throw a li'l microbevel on it and call it done and your "insurance factor" is back at an appropriate level. Remember--efficiency and resilience are typically at almost direct odds to one another, and it's about optimizing the balance between them. As an old Irish agricultural journal once said of axes, "edges should generally be as thin as is consistent with requisite strength." :thumbsup:
 
FortyTwoBlades said:
Austrian blades are frustratingly soft to me. You'll find in videos of users of the continental European type that many of them use a lot of speed in the stroke to compensate for the dulling that occurs almost immediately with their edges. To keep them as keen as I insist on I have to hone after ever 6 strokes or so. Of the Euro-style blades out there I find the Russian ones to take and hold an edge the best. They're almost as hard as an Austrian-made American-pattern blade, though still a touch softer, and the Austrian-made American blades are soft compared to the historical norm. I'm actually working with Arti of Russia right now to get new American pattern blades made to my own specs. They just did the first experiments with forging an American-style cross section yesterday! :)
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We obviously need to chat. I'm keen to hear more about your scythes. (See what I did there? :p)

Maybe a new thread...and definitely a phone conversation at some point.
 
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