Scott321,
I will admit, I don't put much stock (or at least, haven't previously) into the names given to knives like those in the photos you just posted. I would say I more tend to look at task at hand (or think about the types of tasks) then a vision for a blade profile(s) and geometry seems to come naturally. Example: Chef's knife ..., what does that really mean with regard to how/what the knife will excell at? Do "chef's" by definition only need one blade shape (maybe they typically only chop & dice ..., then as they perform other tasks they take on a different designation like Butcher, apprentice parring cutter, master carver, sous chef, etc.?, and the term Chef is reserved for the flashy & speedy chop-chop-chop, & rock-n-roll ...?). OMG, I just did a tongue in check search for "sous chef knife" and came back with a bunch of hits with various blade profiles indicating perhaps a "sous chef" has a larger arsenal of tools than a mere "chef". Maybe on to something here :-O (learning wise for me).
Alas, I again expose my ignorance for these terms and the significance of their meanings in the cooking & food prep world.
With regard to rolling vs. chopping I believe the most significant changes to blade geometry (that will have a performance effect would relate to belly near the tip (allow rolling/rocking cutting motion to elevate the cutting edge higher to clear taller product while still anchoring the blade on the cutting surface & not digging in and/or doing damage to cutting surface and/or blade tip), or belly near the mid-section (ulu profiles on the extreme side, etc.) that will more require a rocking motion when cutting on a flat surface (applies to more difficult to cut foods like meats & cheeses, etc.) but, will begin to excel in skinning duties where a more pronounced belly can be beneficial.
Regarding the four blades (pictures) in your most recent post, there's a pretty good mix of features I see that relate much more heavily than just comparing chopping to rocking cutting action. I think all four would perform either of those tasks fairly comparably with respect to the amount of belly vs. the overall length of the cutting edges. The exception I see would be knife #2 Butcher as that aggressive forward belly would allow significantly great depth (or height depending on perspective) of cut in a rocking technique where the front part of the blade (again matter of perspective forward vs reverse grip - will expand a little below on this) is kept in contact with cutting board. Similarly a longer blade would also have these same increases in cutting height in rocking fashion as the increased blade length naturally would increase the height above the board while staying in contact at the tip portion.
Some of the differences I see (not really having any specific consideration to your questions related to rocking vs chopping):
Knife 1 titled chef's knife classic:
I see a relatively consistent edge profile with a moderately progressive belly increasing near the tip.
I would expect universally even performance in a multitude of cutting (chopping, rolling, slicing, etc.).
Performance enhancing geometry would include:
- Forward belly - reduces snagging the tip in chopping, etc.
- Forward belly - increasing the rock-n-roll performance.
- Forward belly - increases in cutting height in rocking fashion
- Overall extended high blade height - directional cutting would be rather linear (limited in directional changes).
- Overall extended high blade height - directional would be easier because of increased mass height.
- Overall extended high blade height - ability to pressure force (with non-dominant hand or mallet) to the spine to cut through thicker tough product.
- Elevated handle and slightly raised ricasso providing clearance from cutting board.
Performance limiting geometry would include:
- Forward belly - limits chopping area as it minimises contact proximity of the cutting edge to the board (more significant when cutting meats and foods the generally are more difficult to cut as they do not split on initiation (potatoes, apples, carrots, peppers, etc.)
- Overall extended high blade height - limits the blades ability to turn laterally as the cutting edge penetrate deeper and product rides up blade.
- Overall extended high blade height - increases stiction of product to blade limiting performance on deeper cuts.
- Overall extended high blade height - increases resistance as blade thickness increases closer to spine when cutting solid foods.
Knife #2 titled Butcher's Knife:
Forward belly - all same general benefits as Knife #1
- Increased forward belly - allows rocking cutting to be higher (clear thicker product with tip area remaining in contact with board).
- Increased forward belly - increases rocking performance when in reverse grip (common when butchering & in general cutting thick sections of meat).
- Increased forward belly - increases safety when in reverse grip as tip is pointed to user and cut force is generally directed down/out/away.
- Overall decreased high blade height - directional cutting stability would be decreased allowing lateral directional changes to say for example parallel cut next to a curved bone (general butchering, sectioning ribs evenly, etc).
Performance limiting geometry would include:
- Forward belly - all same general limits as Knife #1
- Overall decreased high blade height - basically the opposite of all listed in #1 above.
Knife #3:
Pretty much similar to Knife #1 with a few exception as follows:
- Shorter blade (obvious limits here, potentially some bennifits also depending on task).
- Relief Pockets Ground into Blade.
- Reduce stiction of food to blade (will cut easier and stick less after cut as there is less contact with the food).
- In this specific example, where where those pockets extend to the cutting edge, may see some serrated edge type bennifits.
- Historically, those pockets did not extend to the cutting edge and were primarily only for stiction reduction in my mind.
- Would be interested to try something like this, compared to same blade with more standardized release pockets that stop above the secondary grind section of the blade.
- Would imagine edge rolling would be much more significant to due the decreased edge cross section directly above the cutting edge unless the overall thickness of the grind was increased (but this would somewhat limit any performance benefits overall - seems this would be a very fine balance of geometry, blade steel hardening/tempering, and primary/secondary grind along with extra consideration for tool care).
Knife #4 referenced as for carving:
I see a long blade, with a proportionally short blade height , and proportionally less belly overall, and think how would this affect performance.
- Overall decreased high blade height - same as positives and negative from #2 knife above.
- Overall decreased high blade height - effectively proportionally lowers the handle elevation above the blade edge, further increasing the blades ability to turn laterally around the handle (especially with consideration that the belly is also proportionally decreased as the blade length has increased).
- Increased overall blade length - ability to cut wider product sections.
- Increased overall blade length - ability to cut thicker product sections in a rock-n-roll technique where tip area would stay in contact with board (caution: tip snagging issues references above).
- In general, first thing that comes to mind is a 30lb turkey and following a breast bone whilst carving up on Turkey-Day. Same would hold true working any large cut where lateral directional changes are needed.
Interestingly, you raised no questions as the the radically differing blade geometries and grinds of those two knives I posted in my last message. Just goes to show how far off my initial interpretations were of you original post ;-O
And, how we dove into cookwear to discuss blade profiles (something I have never experienced).
I for one would like to see more of this type of discussion, awareness & appreciation for our tools as it relates to the bladed tools we carry/use daily/weekly. I am looking to make some significant changes to way I grind some of my tomahawks to test out some options related to cutting performance and various applications as a tool I really enjoy using.
Please take anything I have written here, as merely my reflections based on past experiences as applied to the examples we have discussed, and NOT any type of circum-factia.
I trust/hope anything I have written here will be corrected if need be by others with more knowledge and or experiences than I.
Hopefully, you are getting your questions answered and are finding something of value here. I know I am learning as I reflect on your questions and perspectives, and as general thoughts and impressions turn into written word
