BCMW's ht chopping impact tests

[BluntCut MetalWorks]

Chiral - a good hunch, I agree:thumbup:

Here is a 2 consecutive frames supports (or seem so) our assessment - edge steered on impact. Which put a high lateral load on the edge, resulted with 2 chips.

Those are nice clean chips, you can see how the bone steered the edge. I hazard a guess: when you chopped the far end of the bone unsupported, you catapulted the other end with enough force that the bone twisted (steered) the edge with it as it went, probably wouldn't have happened if you could hold the end of the bone like you can with the longer dowel-rod or broom handle. That said, it demonstrates the fragility-threshold of the edge geometry and matrix...

 

[the possum]

I hazard a guess: when you chopped the far end of the bone unsupported, you catapulted the other end with enough force that the bone twisted (steered) the edge with it as it went, probably wouldn't have happened if you could hold the end of the bone like you can with the longer dowel-rod or broom handle. That said, it demonstrates the fragility-threshold of the edge geometry and matrix...

We must tread carefully here, because it could also demonstrate the difference between a controlled test vs. real world use.

 

[BluntCut MetalWorks]

:thumbup: Agree

My perspective (rambling) on controlled ...

Cutting/chopping activities in controlled, especially with close-to-zero lateral force vectors (blade normal/perpendicular to material for the whole interaction) most likely to remain intact because steel strength is 1-2 order of magnitude(ten to hundred times) stronger than common materials. While a 100% lateral force vector(90 degrees off perpendicular), steel strength still apply but load is at minute quotient due to thin edge vicinity. This 100% lateral interaction psi could easily exceed steel strength & toughness at the edge.

A true push/chop = where position of Y (axis / longitudinal direction) is static for the entire interaction. So even in a very well laboratory 'controlled' tests, biases/errors are integral in the data, which warrant sufficiently large sample set for drawing high confident statistical conclusion.

We must tread carefully here, because it could also demonstrate the difference between a controlled test vs. real world use.

After thinned this 11" W2 gyuto blade to about 0.09"/2.2mm thick and took 2 hrc readings at ~0.05"/1.27mm cross section - 67.5rc, where 67 is my targeted/expected hrc. Whew!

 

[Chris "Anagarika"]

Luong,

So the 66HRC posted earlier only estimated?

Also, I don't quite get it. A knot in wood steering edge is easy to understand as the blade & knot has almost nowhere to go. However the rib bone doesn't seem to have enough thickness to steer and quite free to bounce off the cutting instrument, i.e. how an object leaving the cutting edge can steer it?

Last question, the W2 is supposedly a gyuto. Does it mean to chop bone as it's intended use?

 

[BluntCut MetalWorks]

Chris - 66rc read(s) near tang neck and surface wasn't flat nor balance on tester anvil. I suspected readings were low but better to stay conservative and restate with higher # later than reverse.

A bullet deflection/ricochet is a good way for envision steering, except the blade inertia continue straight ahead. 1st frame shows (probably) bone caught and slip sideway steered edge - so the blade temporary off-perpendicular. 2nd frame blade orientation(probably by my holding) is restored after exited the bone.

Gyuto != bone cleaver. 3 main reasons for this test:

1) how my latest hardening ht step applies to my previous different prepared structure (for higher wear resistance)

2) edge stability at 0.015"BET/15dps in chopping impact

3) projection - gyuto specific edge would support incidental bone contacts w/o silly damages

* if change its edge geometry to 0.04"BET/25dps, it then becomes a 67+rc bone (possibly a nail) cleaver

Luong,

So the 66HRC posted earlier only estimated?

Also, I don't quite get it. A knot in wood steering edge is easy to understand as the blade & knot has almost nowhere to go. However the rib bone doesn't seem to have enough thickness to steer and quite free to bounce off the cutting instrument, i.e. how an object leaving the cutting edge can steer it?

Last question, the W2 is supposedly a gyuto. Does it mean to chop bone as it's intended use?

 

[Chris "Anagarika"]

Thanks.
Got it now. The blade was 'pulled' to the left when the bone bounced off to that direction in the middle of the cut.
This shouldn't be a problem if it's meant to process meat with occasional contact with bone but not for bone chopping.
:thumbup:

Edit to add, checked it out: gyuto (牛&#20992 literally means 'beef knife'.