Too much sharpening=dulling?

E

edcrefiner

Joined
Aug 26, 2010
Messages
270
Hi,

I got a lanksy 4 rod sharpener with 2 coarse rods and 2 fine rods. The thing is supposedly pretty good and is supposed to be capable of making knives shaving sharp. This is the problem that I am having:

I have a knife with AUS8 steel. I sharpened on the coarse rod until it is capable of cutting paper with the grain but has a hard time cutting against the grain. From what I gather I should sharpen with the coarse rod (which is actually pretty fine compared to 1000 grit paper and a cheap sharpening stone) until I can cut paper easily. I try and try to stay on the coarse rod but after a while it actually dulls the knife and there is regression on sharpness. I then have to start sharpening with more force until I am back at the previous level. Because of this I hover around the point of barely paper cutting sharp before I am forced to switch to the fine rods because there is no more progress.

Same story with the fine rods. I get some progress and then the sharpness levels hovers at a certain level. Sometimes it deteriorates and I have to start like when I started with the fine rod.

Because of this it is hard to actually get a sharp knife. After tinkering for weeks I only get a barely sharp knife... barely paper cutting sharp. Any tips? Thanks.
 
Clean rods work. Dirty ones don't. Scouring powder on a nylon (no metal) scouring pad works well.

Use very light pressure against the rods. Yes, I mean very light. Take a couple or three passes and slightly turn the rods, so you are always using clean rod. One more thing; you Must keep the knife vertical to the very best of your ability, and you Must keep the blade at a 90* angle to the rods. That means from top to bottom of stroke, always.

You have two sets of holes. Use the straighter holes with the brown rods until you get sharp enough to cut paper. Now use the white rods in the flatter holes. Use light pressure and concentrate on the other things I've mentioned. Go slowly so you know you are making good strokes. About ten strokes on the white rods, and you should be shaving arm hair. If you aren't, go ten more, without leaving any of these directions out.

Please report back ASAP.
 
You are using too much pressure. After you get the initial paper cutting edge you need to back off a bit. Just the weight of the blade is enough.

And go slow. You don't want to bang your edge on the crock sticks.
 
grizzled gizzard said:
Clean rods work. Dirty ones don't. Scouring powder on a nylon (no metal) scouring pad works well.
Click to expand...

Very important. Remembering this can save you a lot of headache. Also, don't worry too much about paper tests etc. Raise a burr on one side, raise on the other and then use lessening pressure to slowly eliminate the burr.
 
As others have emphasized here, light pressure is key. Especially with the round rods, just a little pressure can exert a lot of force on a small portion of the blade edge. Too much pressure will easily bend or break the fine edge. When you've just reached that point where the edge seems to be cutting pretty well, that's your cue to take it VERY LIGHT from there on. Maintain a steady angle, but with a very light hand, and just a few strokes at a time. Check the edge frequently during this phase, to make sure you're still progressing in the SHARPER direction, and not undoing your previous good efforts.

Keeping the rods clean is good sharpening practice too (as with any sharpener).
 
Thanks all for reading my extremely long detailed post. Also thanks for the sage advice. I can always count on getting expert opinions here. I will try your tips after my midterms are over.
 
Grizzled Gizzard, I tried your advice combined with some other posters. And yes indeed it worked like a charm. I haven't got it hair shaving sharp but it is not miles sharper than it was before.

Some advice that I would like to add on to whoever searches this and uses it for reference:

1. Seriously use very very little pressure. Almost let the weight of the blade carry it down the rod. I thought that moderate pressure was the best. However for a kinda sharp blade use little pressure.
2. Concentrate on making sure that EVERY stroke "hits home".
3. Strop when you are done. I found that this rod system still leaves noticeable burs though small ones. I don't have any real strop so I used a university newspaper. It works great for removing small burs. You should be able to tell the difference.
 
I have a lansky too. It just my thought that after awhile, you get that edge so fine that it will break off at the micro level, appearing more dull.

Remember that the coarse stone is for removing large amounts of metal. The more pressure you apply the more metal its going to remove. I would get the angle with the corse stone for the first sharpening, then when it will cut paper go to the fine or ultra fine.

Any sharpenings after that, since you already have the angle, the coarse stone isn't even needed. I'll just use the medium stone, with light pressure, until the knife is pretty sharp, almost shaving sharp, then go to the fine. One trick is to feel the back side of the blade after sharpening one side. You'll feel the burrs of the rough edge. Then sharpen that side until the burrs are gone and you have them on the other side. You'll notice that with different amounts of pressure you get a rougher burr. I just keep going, varying my pressure, untill all the burrs are gone that i can feel with my thumb. With the fine you don't need much pressure eaither. Its just polishing the blade to remove micro burrs and tool marks. It'll make you extra sharp. That should get you shaving sharp pretty quick.
 
edcrefiner said:
Grizzled Gizzard, I tried your advice combined with some other posters. And yes indeed it worked like a charm. I haven't got it hair shaving sharp but it is not miles sharper than it was before.

Some advice that I would like to add on to whoever searches this and uses it for reference:

1. Seriously use very very little pressure. Almost let the weight of the blade carry it down the rod. I thought that moderate pressure was the best. However for a kinda sharp blade use little pressure.
2. Concentrate on making sure that EVERY stroke "hits home".
3. Strop when you are done. I found that this rod system still leaves noticeable burs though small ones. I don't have any real strop so I used a university newspaper. It works great for removing small burs. You should be able to tell the difference.
Click to expand...

Thank you for saying so, that is very kind of you. I am very happy for you as well. It is so rewarding to have a success story like this. :thumbup::D
 
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