General question on blade tip sharpening angles

[Rey HRH]

Waiting on my DMT Diasharp stones to arrive (thanks to someone here who posted knifeworks had a 5% discount through the weekend).

My question comes after having used my Lansky and realized it sharpened at a more acute angle at the tip. As I mentioned in other threads I started, I'm on a learning kick. Just finished 3 books on sharpening and the first of Murray Carter's video. (I realize now there are differences of views).

Here's my question: I was thinking in terms of an EDC knife that might be used to puncture something but I think it applies to all knives. Say, for the sake of argument, that you bevel the rest of the knife with a 15 dps (a very acute angle to me at this point). Given that the blade tip has less material surrounding it and wanting to theoretically maintain the same strength for the tip as the rest of the blade, wouldn't you need a less acute angle for the tip like maybe 20 dps or even 25 dps? Or would you keep it the same 15 dps as the rest of the blade?

I understand the difficulty of maintaining a specific angle at the tip and the transition area between the tip and the rest of the body, at least for me. So I'm just asking the question with specific numbers to convey the general question of whether the tip should have a more obtuse sharpening angle relative to the rest of the blade to maintain the same strength as the rest of the blade.

Thanks for your help.

 

[Sadden]

I leave it all the same angle. Generally unless the blade has a really amazing distal taper , as the edge gets closer to the spine it gets thicker naturally. This is why you see some edge pro jobs where the bevel gets really wide towards the tip.

 

[bdmicarta]

The geometry at the tip can get very complicated- especially with FFG blades the edge near the tip gets thicker than the rest of the edge. Some companies may fudge on the FFD to make the edge thinner near the point. I've seen factory sharpening jobs that had the same width edge near the tip but to make that work the angles got a lot bigger. I reprofiled one of those and the edge got a lot wider near the tip. (This is one thing I admire about Tantos- the blade grinds are honest.) So my answer to the question is that I try to keep the same angle all the way down the edge. But I think if a person wanted the tip to be stronger they might sharpen at a different angle out there. I was watching a video by CRK and they were talking about the hollow grind near the tip being more 3-dimensional I presume to get the edge the right thickness, and they said they still haven't perfected this.

 

[bgentry]

Given that the blade tip has less material surrounding it and wanting to theoretically maintain the same strength for the tip as the rest of the blade, wouldn't you need a less acute angle for the tip like maybe 20 dps or even 25 dps?

The answer lies in how you want to use the blade. I don't do anything with the tip of my EDC or kitchen blades that requires strength. In my case, the pointier the tip, the better. So I pretty much follow the factory lines all the way out to the tip. I guess for some kind of camping tasks you might want a strong tip. Or for non-knife uses like prying and using it as a screwdriver, both of which are stupid IMHO, but people do it. Just not me.

BTW, I find that most sharpeners don't really get to the tip properly. It takes a bit of extra effort and concentration to really get to the very tip of the tip, but it's well worth it if you like a sharp tip.

Brian.

 

[SoulWatcher]

I'm quite new to the forums here but I was wondering if anyone could point me, pun intended, in the right direction on a good manual, book or any such literature on what all the different types of grinds are,what they do and mean. I need something remedial. Everything from what different knife styles are for and best for and how to sharpen your blades; what is the best grind for specific blades,so on and so forth. Any help would be much appreciated.