8Cr13MoV making me crazy

[Scotty]

I have been trying to sharpen a friend's Kershaw 1830 with 8Cr13MoV steel.
I have sharpening for several years with pretty good success (sub100 BESS as a consistent goal).
This knife is making me crazy.
I have set a 15deg bevel(30deg included) on a T8 with a CBN80.
I have been trying to raise a burr with a CBN160 wet,edge leading, and cannot.
I have reverted to the SG 250 (coarse) - to no avail.
Any advise would be a appreciated

[cbwx34]

I have been trying to sharpen a friend's Kershaw 1830 with 8Cr13MoV steel.
I have sharpening for several years with pretty good success (sub100 BESS as a consistent goal).
This knife is making me crazy.
I have set a 15deg bevel(30deg included) on a T8 with a CBN80.
I have been trying to raise a burr with a CBN160 wet,edge leading, and cannot.
I have reverted to the SG 250 (coarse) - to no avail.
Any advise would be a appreciated

Kershaws often have one side that they debur at a really high angle... it can be difficult to remove that last "little bit" to reach the very edge.

My usual advice is to return to the basics... mark both sides with a Sharpie, make a couple of passes on each side, and see where you're removing metal... you might need some magnification to see it clearly.

I actually wouldn't use an 80 grit wheel all the way to the edge either... that can be just as hard to clean up.  If you did go all the way to the edge with it, consider making a couple of 90° swipes on the wheel (with the Tormek off) to give you some fresh metal to work with.

The standard wheel should be more than adequate, and it should come out Oso Sweet.

[3D Anvil]

I'll second cb's recommendations.  One thing to keep in mind is that the edge may have been burned by the factory.  Manufacturers almost always use belt sanders for rapid throughput.  If they're too aggressive, they can ruin the temper of the edge, which can extend as much as a 1-2 mm.  If the heat treat is messed up, the edge will just crumble instead of forming a stiff burr.  All of which is to say that you might need to sharpen a bit *past* the apex to hit good steel.

[cfmiles]

Greetings from Boise Idaho (US). I have been sharpening for several years but have not done a lot of knives with the Tormek. So, since getting ahold of jvh's tormekcalc spreadsheet have been doing as many knifes as I could get my hands on. So far I have gotten close to the better (or even average) reported Bess scores; I am not worried about this as I believe better scores will come with time.

What bothers me is my inability to keep the bevel nice and even, especially toward the tip. I have attached an image to this post. Can somebody help, what am I doing wrong? I have tried placing the jig on different parts of the knives' spine but have gotten the same results. I have also tried altering the horizontal movement of the jig along the support as the tip is approached. No change.

Thanks in advance,
cfm.

[3D Anvil]

What bothers me is my inability to keep the bevel nice and even, especially toward the tip.

It's interesting that you're getting a wider bevel at the tip.  The normal result, if you follow Tormek's general advice to move the jig parallel to the USB and only lift your elbow to hit the belly/tip, is a smaller bevel.  That's because the bevel angle gets steeper as you get higher on the wheel.  Are you using that method, or are you pivoting the jig?

[tgbto]

It's interesting that you're getting a wider bevel at the tip.  The normal result, if you follow Tormek's general advice to move the jig parallel to the USB and only lift your elbow to hit the belly/tip, is a smaller bevel.  That's because the bevel angle gets steeper as you get higher on the wheel.  Are you using that method, or are you pivoting the jig?

Although it's true that you will get a wider bevel if you don't lift and pivot the tip away from the USB, I found that depending on the shape of the blade itself (taper angle and edge curvature mostly), sometimes lifting is not enough and you have to pivot the tip closer to the USB to get the steeper angle required to keep the width even (reverse-pivot).

That also depends on where along the blade you clamp the jig. It helps maintain control in the tip area where lifting only might result in so little of the blade contacting the wheel that it ends up messing up the tip. The sharpie is your best friend when trying to find that sweet-spot combination of lifting and pivoting one way or the other.

Although they say little about this pivoting in the videos, you can see Wolfgang pivot one way or the other if you watch closely of some of them. He explains why in the advanced sharpening video, when he explains the different kinds of blade geometries.

[cbwx34]

Greetings from Boise Idaho (US). I have been sharpening for several years but have not done a lot of knives with the Tormek. So, since getting ahold of jvh's tormekcalc spreadsheet have been doing as many knifes as I could get my hands on. So far I have gotten close to the better (or even average) reported Bess scores; I am not worried about this as I believe better scores will come with time.

What bothers me is my inability to keep the bevel nice and even, especially toward the tip. I have attached an image to this post. Can somebody help, what am I doing wrong? I have tried placing the jig on different parts of the knives' spine but have gotten the same results. I have also tried altering the horizontal movement of the jig along the support as the tip is approached. No change.

Thanks in advance,
cfm.

Gotta be honest... that's not a difference I would worry about.  Bevel width can change for a number of reasons, for example, blade gets thicker, angle change, etc.  Unless it's drastic, I'd leave it like it is... it'll probably be a little sharper that way, anyways.

p.s.  If you start doing too much rotating/pivoting/etc. trying to make bevels even, you can end up altering the tip.

[John Hancock Sr]

The important detail is to make sure that whatever part of the knife is touching the stone should be the same distance from the support bar. This is why it is important to "lift" the knife handle, not rotate it. The instinctive response is to rotate so you really have to think about it when you get to the tip.

One trick that Tormek suggest is to get a square and draw a line across the wheel. Position the line so that the edge of the knife is resting on the line then without turning on the machine draw the knife across the wheel as if you are sharpening and make sure that the edge touching the wheel is always touching the line you drew on the wheel. This way you will see how you need to move the knife when actually sharpening.

[tgbto]

The important detail is to make sure that whatever part of the knife is touching the stone should be the same distance from the support bar. This is why it is important to "lift" the knife handle, not rotate it.

I'm not sure I follow you : if your edge curves upwards (as on most western chef knives) and you lift, you get closer to the USB, don't you ?

One trick that Tormek suggest is to get a square and draw a line across the wheel. Position the line so that the edge of the knife is resting on the line then without turning on the machine draw the knife across the wheel as if you are sharpening and make sure that the edge touching the wheel is always touching the line you drew on the wheel. This way you will see how you need to move the knife when actually sharpening.

As shown by Tormek at this point in time in the advanced sharpening video, if you only lift you can't follow the line (except on a nakiri-type knife obviously). I think Wolfgang sums it all when he says "You can have any jig you want, you have to control and train these movements". But as mentioned in numerous other posts (look for "pivot jig") pivoting is not ideal either. Control and training make sharpening on a Tormek an acquired skill.

[John Hancock Sr]

I'm not sure I follow you : if your edge curves upwards (as on most western chef knives) and you lift, you get closer to the USB, don't you ?

Yes - depends on the curvature, hence why I add the line trick. Instinctively one tends to rotate the knife without lifting it (I have seen sharpening videos where the person rotates the knife) which gives the result above.

[Thy Will Be Done]

I have been trying to sharpen a friend's Kershaw 1830 with 8Cr13MoV steel.
I have sharpening for several years with pretty good success (sub100 BESS as a consistent goal).
This knife is making me crazy.
I have set a 15deg bevel(30deg included) on a T8 with a CBN80.
I have been trying to raise a burr with a CBN160 wet,edge leading, and cannot.
I have reverted to the SG 250 (coarse) - to no avail.
Any advise would be a appreciated

Advice : DO NOT ever set out with the goal being raising a burr.  I know this is common dogma in sharpening, first raise a burr then remove.  I get it, I try to avoid forming a burr.  Get the apex thin to where it's slicing newsprint and then switch to the finishing stone or leather wheel and make a few light passes.  Drink a beer and celebrate life.  No burr necessary.