Sharpening question (lansky system)

alude904

alude904

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So I will admit that I'm pretty new to sharpening. With that in mind, I just picked up a Lansky sharpening system. I've decided to sharpen my Tom Krein k9. So far it's uses have been primarily for camping/bushcrafting. I figured for that purpose, it would have a pretty big angle so I put the rod through the 30 degree slot. to my eyes it looks flush with the angle Tom has. I then put it in the 25 degree slot. It looked pretty flush but not as much. Remember, this is just me eye-balling it for now. Then I put it in the 20 degree slot. It didn't seem flush. I then took a dry erase marker and marked the edge. My first swipe was with the medium stone on the 30 degree angle. Not too much force as I wanted to see what happened to my mark. turned out 30 degrees was too wide. I then took it down to 25 degrees. Still too wide. I took it down to 20 degrees. That ended up being the angle Tom has on this knife as it cleanly took my mark off. Going by Lansky instructions and just general knowledge, I always thought that having a narrow blade (especially 20 degrees), wasn't the best angle for chopping wood. If that angle is fine then I'll continue to sharpen it there but if 25 or 30 degrees is better, should I re-profile it? Thanks for any and all help.
 
I guess I would be using it for some food prep as well so what would be a good medium?
 
update: so after check both sides of the knife using the same marking method, it seems like one side is 20 degrees while the other side is at 25 degrees. could that be right or is it user error?
 
I think the error is on my side as I noticed that the blade can move up and down while in the clamp. I'll try to make the blade for secure and then try my method to figure out the original angle
 
Okay so after securing the blade better, It seems now that both sides are ground at 20 degrees. My initial question still stands. I'm sure this must be entertaining for people to read as I learn.
 
Keep in mind, with the Lansky system, the actual angle will not likely match the setting on the clamp. Any blade edge which extends further than the front edge of the clamp will sharpen up at an angle that's lower (less) than the indicated setting. For example, a typical traditional folder's main blade is often around 1/2" - 5/8" wide (edge to spine). If clamped in the notch at the front of the clamp's jaws, the blade edge will be roughly 3/8" - 1/2" in front of the clamp's jaws. At that position, using the '17' setting on the clamp will produce an edge angle closer to 15° (per side). I know this from measuring & calculating it in my own uses of the Lansky. The marked angle settings on the clamp are as measured to the immediate front edge of the clamp, and it's not possible to reach the edge of the blade in that position. All of this means that very wide blades will often end up with edge angles that are much more acute than the marked setting used for the guide rod.

Based on what I've seen in the online description/specs/pics of your knife (Krein K9), it looks like a pretty wide blade (1.5" or wider?). If so, it's true edge angle relative to the marked settings on the clamp is likely quite a bit more acute than you probably think it is. Only way to know, is to measure and/or calculate for it.


David
 
Thanks for that information. My system does not have the notch in the front like the others have. Weird? that doesn't bother me though because i don't carry or own any small knives. Also, I had the knife clamped pretty far back into the system so there wasn't too much blade sticking out. I assume doing that and with your explanation, the notch that the rod was in (20 degrees) was pretty close to being accurate? Going back to one of my questions, for the use being mainly chopping, carving, and battoning wood as well as a little food prep, is that angle too acute? Could there be possible chipping with it being that thin? I'm not sure what angle bushcrafters usually stick with. Oh and the steel is 3V.
 
alude904 said:
Thanks for that information. My system does not have the notch in the front like the others have. Weird? that doesn't bother me though because i don't carry or own any small knives. Also, I had the knife clamped pretty far back into the system so there wasn't too much blade sticking out. I assume doing that and with your explanation, the notch that the rod was in (20 degrees) was pretty close to being accurate? Going back to one of my questions, for the use being mainly chopping, carving, and battoning wood as well as a little food prep, is that angle too acute? Could there be possible chipping with it being that thin? I'm not sure what angle bushcrafters usually stick with. Oh and the steel is 3V.
Click to expand...

Whatever the edge angle is at now, the best thing to do is to use the knife for a while and see how the edge holds up, and balance that against how it cuts. A thinner edge angle is obviously better for the bushcraft, carving & food prep tasks. Might just go easy on it initially, with the chopping & batoning. I don't have any 3V blades, but I don't think it's too fragile, based on what others seem to think about it. It apparently has a great reputation for toughness (resistance to breakage from impact/shock), so I think that works in your favor. Doesn't sound like it's prone to brittleness. If anything, the edge might roll/deform if it can't hold up to the chopping/batoning. If you do notice any of this, that's the best indicator the edge angle might be too thin.

The downside to making the edge thicker from the start is, it certainly won't slice/cut as well in the finer tasks. That's why you need to decide which uses of the knife will be more important to you.


David
 
As OWE (David) said, the angles are not as it says on the clamp. Steve Bottorff (Sharpening Made Easy) said the Lansky is 3-5˚ lower than indicated. I have noticed a lot of edges seem to match at the 25˚ setting (probably 20˚ for real). Once you know that, it helps you to decide which angle to use. Just see if the angle is working for you.

One thing to remember with the Lansky also is to make sure the rods are straight.

Good sharpening,
Dave
 
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