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Sharpening New Blades/Heat Damaged Blades

Posted by jasonstone20 
Sharpening New Blades/Heat Damaged Blades
September 22, 2017 09:16AM
With some knives having some damage to the edge from factory sharpening, I have noticed a few things:

First: Usually will take a 3*90 phone-book paper push cut and shaving edge.

Second: Won't take an edge that will pass a Hanging Hair Test 3/4/5, but sometimes will whittle hair barely, has trouble tree-topping.

Third: Slicing aggression is not what it could be.

Fourth: Using a guided system helps overcome these issues somewhat until you sharpen enough times (3 times or more) to get to undamaged steel.Why this is I don't know.

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser
Re: Sharpening New Blades/Heat Damaged Blades
September 24, 2017 10:56AM
Factory edges are usually not evenly ground, hence a guided system is likely to get you to correct that. If you freehand you might not notice you are not hitting all of the edge evenly and end up with parts not actually being cut. This is one of the main reasons that having a decent jig is of benefit initially. Of course you can do the same thing freehand (just pay attention), but jig just makes it really obvious.
Re: Sharpening New Blades/Heat Damaged Blades
September 24, 2017 12:18PM
Cliff,
I like to first reprofile the edge freehand with a XC SiC stone, almost to a zero grind so i can easily cut a new bevel using the lowest or second to lowest setting on the clamp systems. I have also noticed, which should be number 5 thing listed, is that stropping on plain canvas/linen and plain leather can bring out high push cutting sharpness on a damaged edge, were if you had undamaged metal you could get that straight off the stone.

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser
Re: Sharpening New Blades/Heat Damaged Blades
December 12, 2017 11:59AM
Cliff,
The more wear resistant and/or the knife stainless, plus damage from use like impacted steel, can the damage be deeper than what you would normally be able to remove with 2-3 sharpenings? I had a knife (Benchmade 940 in S30V) recently that took 10+ sharpenings before I started to get into the undamaged steal. I was looking for a cause of that, and thinking it could be a reason for reports of a bad steel and or knife when it doesn't act normal after 2-3 sharpenings or even 5.

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser
Re: Sharpening New Blades/Heat Damaged Blades
December 13, 2017 09:16AM
Yes, the damage could be very deep if the knife was heavily stressed. On knives power sharpened heavily, you can have ~ mm of edge which can't function properly.
Re: Sharpening New Blades/Heat Damaged Blades
December 23, 2017 06:52PM
So, to summarize:
For heat damaged blades, I have found that guided systems, diamond and sintered ceramics are the most effective in getting an edge that is above arm hair sharpness, but below HHT/free hanging hair cutting, and can treetop. Usage of strops is a mixed bag, the harder the backing the better the results.

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser
Re: Sharpening New Blades/Heat Damaged Blades
October 18, 2018 05:48PM
The Spyderco Sharpmaker is good for damaged steel also. I was able to get a high sharpness edge on damaged steel, and it still had slicing aggression.

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser
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