Different angles, same blade

J

Jahaworth

Joined
Jun 3, 2009
Messages
15
Hi all.
Just a quick question.... I recently brought a really nice Kershaw speedsafe pocket knifewhile on Holiday in the States. While it came sharp I wanted to sharpen it to my own standard. I use a Lansky system & using it I can get all my knives shaving sharp. Anyway, when I was sharpening the new Kershaw I discovered that the factory angle is 20deg on one side & 25deg on the other. Is this normal? Is there some advantage to this? With me using 25 on both sides I now have a full edge on one side & I suppose a micro bevel on the other. It's still shaving sharp.... but it bugs me.
Thanks all for your time.
 
This is all too common with many production knives, and the better mfgs are not immune (Kershaw, Benchmade). It's safe to say the difference from one side to the other is not intentional. In extreme cases it needs to be ground to a more symmetrical form or it makes it difficult to properly maintain the knife.
 
Jahaworth said:
I discovered that the factory angle is 20deg on one side & 25deg on the other. Is this normal? Is there some advantage to this? With me using 25 on both sides I now have a full edge on one side & I suppose a micro bevel on the other. It's still shaving sharp.... but it bugs me.
Thanks all for your time.
Click to expand...

Is this normal? NO. :mad:
Is there some advantage? NO :mad:

Is this all too typical? Unfortunately, YES. :(

The bad news is, a lot of manufacturers are this sloppy. The good news is, since you're already reprofiling with your Lansky, you're going to make your edge MUCH BETTER. If it's already shaving sharp now, even with the mis-matched bevels, then it should be WICKED sharp after you've balanced and refined them. :)
 
When it comes to factory edges, unless it is a convex grind, you will almost always find small differences in the angle of the secondary bevel which is ultimately translated on the size of the bevel in both sides also, which in this case makes them appear asymmetrical. I am a fearless factory edge interventionist!! I'm never pleased with factory edges, even if they "appear to be" shaving sharp. Normally, the secondary edges of flat grind knives and hollow grind knives are too obtuse for my taste so I normally increase the angle if I want to keep it as a secondary bevel or just transform it to a convex secondary bevel. I have done the latter with almost all my flat grind knives, like:
RAT-7
Becker BK7
Kershaw Bear Hunter
Ontario SP-21 Magnum
Ranger SHIV
Cold Steel Recon Scout
Others that can't remember right now.

What I achieve doing this is increase the angle of the edge but at the same time I give it better support. I also don't need to worry anymore on keeping the angle of the secondary bevel every time I re-sharpen; I just run it slightly on a fine ceramic rod and then strop it with black and green compound. The results are amazing (for me at least). And lastly I don't have power tools to do this I just use my Norton water stones (320-1000, 4000-8000) and a couple of diamond stones to start the job.
KUDOS to the daredevils that sharpen their own knives :cool:
 
Thanks for your advice guys. I'll reprofile both sides to 20deg and then finish off with a 25deg.
Thanks again.
 
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