Edges from Factory

K

knife chop

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Feb 11, 2014
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we all know that most factory edges does not come as sharp as we'd like but there's another thing I noticed. why are some knives when sharpened from the factory, the edge is straight but it slightly curves towards the ricasso? I have no pictures to provide but the knives I've seen with this issue are the Tops Tex creek, freeman outdoor gear and anza knives? thoughts?
 
I'd guess that most knives are sharpened by a human being. That being said you can't guarantee more than a general similarity between knife edges. Have you ever done repetitious work? I've worked an assembly line for a bit and it was one of the worst, most boring jobs ever...you become mind numb and are just going through the motion once you've mastered the skill.
Not all edges are going to be perfect...learn to live with it and reprofile every knife you your standards and you will get a better knife out of it, and one that gives you more satisfaction for being what you want.
 
Not a perfect edge from factory because they are sharpened by hand on a belt.
Invest in a rig to sharpen your knifes; as the will eventually get dull anyhow.
 
I get it but your guy's answers are not really valid. I want a perspective coming from a knifemaker or a seasoned knifenut.
 
I think you are referring to the slight recurve towards the ricassio that many factory & custom knives can have?

When sharpening on a belt or even a flat stone etc, many give more pressure when they start the sharpening pass and back off on pressure as the draw the blade across to avoid damaging the tip.

This is not good on a culinary Chef/chopping knife but can help in cutting with meat/Boning Fillet and hunters and of course a recurve fighter.

Is that what you are referring too/asking about?
 
I've seen this recurve on many factory edges, including TOPS, Bark River, Benchmade... I attribute it to the use of a belt system and either too much dwell time on the heel or some other symptom, a slack belt maybe?
 
HeavyHanded said:
I've seen this recurve on many factory edges, including TOPS, Bark River, Benchmade... I attribute it to the use of a belt system and either too much dwell time on the heel or some other symptom, a slack belt maybe?
Click to expand...


Could it be its because they don't use a fixture when sharpening? I've seen Ray Ennis (Entrek knives) and Guy Seiferd (Survive! knives) placing a fixture on the knife and using a slack belt to sharpen.
 
It seems that a lot of knives nowadays (esp. folders) have a slight recurve toward the heel (ricasso) as the op stated. While i agree that it may be because of sharpening technique at the factory, it sure seems that they were deliberately designed that way. On many that i have seen it sure seems like it would take A LOT of metal removal from sharpening to get that recurve. (Obviously i am not talking about knives with a significant, purposful recurve like the crkt shenanigan, boker jim wagner reality series, many 5.11 models, etc.) CRKT seems to be the biggest offender in this. Im guessing that it is done on purpose because it seems to me that it is most common on less expensive knives (but not always). I think most of us when we were first getting into the hobby that we were attracted to the organic blade shapes. My guess is this is just a way for companies to appeal to the general public and drive sales in brick and mortar big box stores. I would assume the VAST majority of folding knife sales under $40 are to people making an impulse purchase, and dont want a knife that looks like their dad's Buck 110 or Case slipjoint.

Just my opinion but who the hell knows. I know that i hate it. And im sure anyone else who sharpens on benchstones hates it too. Sure, i grind it off and get a nice, straight edge but it is definitely a hassle. Sometimes it takes a fair amount of stock removal and time to get rid of even the tiniest recurved heel. Even with the Atoma 140 on the EPA. Still, most of my sharpening i do freehand and its a P.I.T.A! Considering how popular serrated, recurve, and tanto blades with skulls, "seat belt cutters", anemic flippers, and rainbow colored knives are with the general public; i guess we'll just have to deal with it. Ok enough ranting!
 
This is how I picture what happens, in producing the 'recurve' near the heel of the blade:

  • Blade's overall profile (primary grind) is applied, including a radiused transition between the thin edge and the thicker ricasso & tang.
  • Blade's edge bevel gets applied with a belt; the edge of the belt will curl/bend laterally as it interacts with the radiused plunge of the primary grind.
  • As the belt 'curls' laterally in the plunge, the blade's edge is angled into the belt to produce the edge bevel. The angling of the blade's edge into the belt means the curl in the belt is interacting vertically up into the cutting edge, producing the recurve in the edge.

Maybe some knifemakers will chime in to confirm or not, but that's what I think is going on, in producing the 'unintentional' recurve.


David
 
Beside some (small) cutting benefits from a recurve edge profile. High production yield is the main reason for having a gentle recurve (where belly is a whole wave crest and heel is starting of another crest). With belt finished edge, recurve help to hide imperfection & corrected manual grinds. Even for skillful makers whose awesome with belt grinding, a straight & center line sharp apex is down right impractical. Corrections - such as fix holes in apex, can get done and extend the recurve slightly -> tada, ship it. Marketing speak - you like curvy look+touch, right :p

I make/like my edge a continuous curve from tip to almost flat toward the heel.
 
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