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TOPIC: Leading or Trailing Strokes

Re: Leading or Trailing Strokes 1 year 7 months ago #8020

  • xuzme720
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PhilipPasteur wrote:
...placebo blades...
Phil
Interesting concept...:lol:
Particpant in finding out how sharp is sharp!
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Re: Leading or Trailing Strokes 1 year 7 months ago #8026

  • Geocyclist
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Very good discussion going on.

I think this can easily be 2 separate studies -

1. is to use an expert operator (Clay) and only one operator to remove the human influence as much as possible to concentrate on leading vs. trailing, as shown by Clay. True any other operator could have different results. This can be repeated by other operators for comparison.

2. A 2nd study to show the affect the human influence, different operators would need everything else constant but the operator. Same blade, same WE, have the blade set in the vice by the administrator each time. I think (haven't tested) the #1 human influence is pressure that creates different results. Also speed, length of stroke etc.

In the end it I think it is hard to remove the human element from sharpening, at least for a controlled experiment, without being able to measure and control critical variables such as pressure.

I searched the web on this one a while and found more questions than answers. I did like this post here.

Key points I picked up were:
  • Some people talk about the edge getting duller as they progress through stones
  • May be due to "snow plow" effect of the blade rolling on edge leading instead of cutting the steel
  • Edge trailing will polish more


Do both leading and trailing on coarse stones
Finish on fine stones with trailing only
Strop

I am now wondering if this is what Clay's photo of edge leading is showing, a rolled or deformed edge? I am very curious to see how this knife does in the same sharpness tests.
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Re: Leading or Trailing Strokes 1 year 7 months ago #8033

  • wickededge
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Something we need to add in is BassLakeDan's point sharpness tester. The data from that test alone would be really useful to determine at least one point of efficacy of varying techniques. Has anyone built one yet?
--Clay Allison
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Re: Leading or Trailing Strokes 1 year 7 months ago #8073

  • FredHermann
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Ok, I have been reading this ongoing, and it's fascinating.
But please forgive my ignorance...I thought I knew what you were talking about, until I didn't.
Can someone please define 'leading vs trailing'? I thought you were talking about going tip to heel or vice versa. Call me a noob, but this one has confused me.
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Re: Leading or Trailing Strokes 1 year 7 months ago #8074

  • Jet B
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FredHermann wrote:
Ok, I have been reading this ongoing, and it's fascinating.
But please forgive my ignorance...I thought I knew what you were talking about, until I didn't.
Can someone please define 'leading vs trailing'? I thought you were talking about going tip to heel or vice versa. Call me a noob, but this one has confused me.

Think of edge leading as if you were trying to cut the medium. Edge facing the direction of movement. Edge trailing is the opposite where you drag the blade across with the 'edge trailing'.

Hope that helps you. It's actually a controversial topic in the sharpening community... haha;)
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Re: Leading or Trailing Strokes 1 year 6 months ago #8079

  • BluntCut
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An edited post (mine) from my thread (not here) 10/31/2012 ...

This 2 images are what I've envisioned a few months back. These are (~ 30% resemblance) my mental images that I stared at for countless hours and they still make sense today as the day I came up with them. Please hold-on to other variables (abrasive shape, steel composition/ht, etc) while we look at this simplified models.

V t/l is the velocity - blade or abrasive movement.

P is the blade normal force against the abrasive.

Av (Abrading Vector) is the cutting vector imparts torque on the blade. The edge will deflect/bend when the torque exceed the tensile strength at given edge thickness.


Burr-nana peel.


Apex deflect or roll but no burrnana.

These models should provide reasonable answer to alot of nagging questions.

ex1: 'how come the burr seem long but blade height wasn't shorten by the same amount?'
burr-nana peel around the apex, so blade height loss usually much less than burr length.

ex2: 'raised burr 2 sides, deburred but didn't apexed?'
Too much press, burr-nana peel around a blunted apex. Once burr removed, you end up with a blunted/un-apexed edge.

ex3: lip
Whenever Av too large for the apex area, abraded area will occur below the apex.
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