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Knife tip geometry!
First things first: no, this is not a comprehensive list of knife tip geometries! There are so many of them - and most of them so highly specialized - that, if you need one of them, you know... XD So, in order to give a "beginner-friendly" overview, I've narrowed it down to four types that are common enough you may actually encounter them in real life without having to look for them in a specialized store.
Let's look at these in some detail! (With the caveat that, of course, tip geometry is not the only thing that determines a knife's overall function. Material matters. Blade thickness matters. Grind matters. Handle design matters. Size matters. XD And so on. Really, this can only serve as a rule-of-thumb - but we have to start somewhere when trying to determine what a knife is for, right?)
1) Straight back.
The spine (as in: the side that's not sharp LOL) of the blade is completely straight, the sharp edge has all the curvature. This is something you will find on many working and outdoor knives (like, for example, a common puukko).
PROs:
- BITEY! The curvature of the edge means more pressure gets concentrated on a smaller area, so, it's de facto "sharper" than a straight edge. (Ask me if you want a breakdown of the physics.) This is the sharpest "standard shape" you can get. The sharpness means you can cut relatively hard materials like, say, wood. On your carving/whittling knife, this is definitely the geometry you want!
- Easy to sharpen: the straight back means it's very easy to maintain the correct angle. (This is especially relevant for outdoor knives like the aforementioned puukko: you may want to sharpen it in the field.)
- Reference: the straight back makes any tasks that require estimating sizes / distances / whatever by eye so much easier... Your cutting path is the most predictable.
CONs:
- The geometry is not ideal for piercing or stabbing.
- Well. It's not particularly beginner-friendly (as in, it's harder to control than most other knife types), so, while you theoretically get some extremely controlled cuts, doing so takes some practice.
2) Drop point.
The tip is slightly lowered by curving the spine slightly downwards. My scribble shows an extreme case that's almost a spear-point (which would be completely symmetrical), but it's usually less pronounced. You will even find some "intermediate forms" between straight back and drop point, where you really need to squint hard to see the curvature. Anything goes.
PROs:
- ECONOMY of force use! On a well-designed drop-point knife, the tip is positioned exactly on the centerline / axis of the force vector. That means the energy you put into the system translates directly into the material; you minimize energy loss. If that sounds a bit too abstract for your taste: you need less force, so, your hand gets less tired.
- Stability! Another nice effect of having the tip on (or at least near) the centerline is that it's less likely to snap off. Knives like this tend to be somewhat forgiving of user errors, so... Beginner-friendly. As far as sharp, potentially dangerous objects can be beginner-friendly, anyway. (Take all the necessary safety prcautions anyway!)
- Compromise! It's a bit "the best of all worlds" in that it's not really super-specialized: it doesn't really excel at anything, but it's also not absolutely terrible at anything. That's also why most "pocketknives" and other EDC knives have this shape: maximal versatility.
CONs:
- Less edge curvature means it's not quite as sharp as something with a straight back.
- Somewhat "blunt" tip means slightly less tip precision than some other knife types.
3) Clip point.
You have a corner in the knife spine - sometimes even a concave curve on the spine near the tip, not just a clipped straight edge.
PROs:
- STABBY! This is the geometry if you want to pierce something with the knife tip. Even if you don't want to stab anyone (which... I hope... though, of course, "tactical" knives often enough use this geometry, too), the tip penetrates materials easily.
- Good fine point control - especially when this design results in a very thin tip with a sharp angle. You want to do some artistic papercutting but can't find your scalpel? (For that matter, look at the shape of the typical scalpel tip, too...) This is what you want for all those lovely details.
(- Probably irrelevant to you, but "tactical" knifes sometimes also sharpen the clippy part, which would put the resulting knife very firmly in the category of "weapon" for reasons I do not wish to explain. Consult a lawyer before even touching anything like that. It's not something you need for any obvious household tasks.)
CONs:
- Weaker tip strength: if you're not very careful, or you use too much force, it will snap off. That's acceptable on a "tactical" knife (if it happens in your attacker's body, it means you defended yourself successfully in the first place, and you're very lucky if all you have to do is buy another knife) but entirely unacceptable on a woodworking knife (where flying metal shards are just dangerous).
- A true PITA to sharpen: you have multiple angles near the tip. (Can be done, of course, but it's not something you want to do in the field.)
4) Wharncliffe blade.
This is something you will, for example, encounter in your kitchen. (Not as a "chef's knife", but likely as one of the smaller paring knives / slicing knives.) The edge is completely flat, after all - it aligns perfectly with the surface of your cutting board!
PROs:
- CLEAN straight cuts!
- Yes, it's really optimized for cutting on a flat surface. You want to slice cucumbers without having to rotate your wrist all the fucking time? This is the knife for you!
- Scraping! I mean. Obviously.
CONs:
- Well, the lack of curvature means it's not very "bitey" (see what I wrote under point 1), so, you probably don't want to cut anything very hard with this type. Heavy-duty chopping is not an option. Better stick to those cucumbers.
- The low tip is also very bad at piercing and stabbing.
Anyway... This (grossly over-simplified, I know) entry will hopefully help you identify what kind of blade you are dealing with, what its strengths and weaknesses are, and what tasks people will likely use it for. (None of this is intended as legal or professional advice; don't sue me, yadda, yadda. If you do dangerous shit with sharp objects, I'm not responsible.)
Let's look at these in some detail! (With the caveat that, of course, tip geometry is not the only thing that determines a knife's overall function. Material matters. Blade thickness matters. Grind matters. Handle design matters. Size matters. XD And so on. Really, this can only serve as a rule-of-thumb - but we have to start somewhere when trying to determine what a knife is for, right?)
1) Straight back.
The spine (as in: the side that's not sharp LOL) of the blade is completely straight, the sharp edge has all the curvature. This is something you will find on many working and outdoor knives (like, for example, a common puukko).
PROs:
- BITEY! The curvature of the edge means more pressure gets concentrated on a smaller area, so, it's de facto "sharper" than a straight edge. (Ask me if you want a breakdown of the physics.) This is the sharpest "standard shape" you can get. The sharpness means you can cut relatively hard materials like, say, wood. On your carving/whittling knife, this is definitely the geometry you want!
- Easy to sharpen: the straight back means it's very easy to maintain the correct angle. (This is especially relevant for outdoor knives like the aforementioned puukko: you may want to sharpen it in the field.)
- Reference: the straight back makes any tasks that require estimating sizes / distances / whatever by eye so much easier... Your cutting path is the most predictable.
CONs:
- The geometry is not ideal for piercing or stabbing.
- Well. It's not particularly beginner-friendly (as in, it's harder to control than most other knife types), so, while you theoretically get some extremely controlled cuts, doing so takes some practice.
2) Drop point.
The tip is slightly lowered by curving the spine slightly downwards. My scribble shows an extreme case that's almost a spear-point (which would be completely symmetrical), but it's usually less pronounced. You will even find some "intermediate forms" between straight back and drop point, where you really need to squint hard to see the curvature. Anything goes.
PROs:
- ECONOMY of force use! On a well-designed drop-point knife, the tip is positioned exactly on the centerline / axis of the force vector. That means the energy you put into the system translates directly into the material; you minimize energy loss. If that sounds a bit too abstract for your taste: you need less force, so, your hand gets less tired.
- Stability! Another nice effect of having the tip on (or at least near) the centerline is that it's less likely to snap off. Knives like this tend to be somewhat forgiving of user errors, so... Beginner-friendly. As far as sharp, potentially dangerous objects can be beginner-friendly, anyway. (Take all the necessary safety prcautions anyway!)
- Compromise! It's a bit "the best of all worlds" in that it's not really super-specialized: it doesn't really excel at anything, but it's also not absolutely terrible at anything. That's also why most "pocketknives" and other EDC knives have this shape: maximal versatility.
CONs:
- Less edge curvature means it's not quite as sharp as something with a straight back.
- Somewhat "blunt" tip means slightly less tip precision than some other knife types.
3) Clip point.
You have a corner in the knife spine - sometimes even a concave curve on the spine near the tip, not just a clipped straight edge.
PROs:
- STABBY! This is the geometry if you want to pierce something with the knife tip. Even if you don't want to stab anyone (which... I hope... though, of course, "tactical" knives often enough use this geometry, too), the tip penetrates materials easily.
- Good fine point control - especially when this design results in a very thin tip with a sharp angle. You want to do some artistic papercutting but can't find your scalpel? (For that matter, look at the shape of the typical scalpel tip, too...) This is what you want for all those lovely details.
(- Probably irrelevant to you, but "tactical" knifes sometimes also sharpen the clippy part, which would put the resulting knife very firmly in the category of "weapon" for reasons I do not wish to explain. Consult a lawyer before even touching anything like that. It's not something you need for any obvious household tasks.)
CONs:
- Weaker tip strength: if you're not very careful, or you use too much force, it will snap off. That's acceptable on a "tactical" knife (if it happens in your attacker's body, it means you defended yourself successfully in the first place, and you're very lucky if all you have to do is buy another knife) but entirely unacceptable on a woodworking knife (where flying metal shards are just dangerous).
- A true PITA to sharpen: you have multiple angles near the tip. (Can be done, of course, but it's not something you want to do in the field.)
4) Wharncliffe blade.
This is something you will, for example, encounter in your kitchen. (Not as a "chef's knife", but likely as one of the smaller paring knives / slicing knives.) The edge is completely flat, after all - it aligns perfectly with the surface of your cutting board!
PROs:
- CLEAN straight cuts!
- Yes, it's really optimized for cutting on a flat surface. You want to slice cucumbers without having to rotate your wrist all the fucking time? This is the knife for you!
- Scraping! I mean. Obviously.
CONs:
- Well, the lack of curvature means it's not very "bitey" (see what I wrote under point 1), so, you probably don't want to cut anything very hard with this type. Heavy-duty chopping is not an option. Better stick to those cucumbers.
- The low tip is also very bad at piercing and stabbing.
Anyway... This (grossly over-simplified, I know) entry will hopefully help you identify what kind of blade you are dealing with, what its strengths and weaknesses are, and what tasks people will likely use it for. (None of this is intended as legal or professional advice; don't sue me, yadda, yadda. If you do dangerous shit with sharp objects, I'm not responsible.)