Dishing on Right Side of Blade

[Mark Greene]

I'm new here and new to using a Tormek. But not new to sharpening. I'm getting some constant dishing on the back third of the blade only on the right side. Left side coming out great - nice even bevel all the way from heel to point. I'm right handed (which controls left side of blade) so maybe left hand needs to learn. Frustrating.

Any advice much appreciated.

Here's a radical example of what I'm talking about.

[tgbto]

I'm not sure what you mean by "left side coming out great" as the apex being concave is something that's true for both sides.

Still, I'd wager you're suffering from one of the classical Tormek new-user syndromes : overgrinding the middle of the blade.

There are many posts about this (look for "overgrind" in the search bar), but there are two important things you may want to try that usually improve this a lot :

• Lay down your blade on the stone as flat as possible, and if you must tilt it ever so slightly, just make sure it is towards the heel (ie lower the hand that holds the handle). It seems to me the maximum of dishing happens at approximately one stone width from the beginning of the grind, which is consistent with a handle hand that's too high.
• Round out the shoulders ("corners") of the wheel so they are less aggressive  when you tilt the blade a bit

Good luck !

[Mark Greene]

Great input, thanks.  I tried other search terms and couldn't find anything.  I'll try "overgrind"

[John_B]

You may be hesitating as you reach the end where you get dishing extending the contact time. Then you grind some more as you start up and go the other way. One way to minimize this is to grind in one direction then immediately remove blade from wheel and reposition to tip and start again keeping even pressure throughout the process. This is where practice on a sacrificial knife helps.

[tgbto]

John, does this mean you sharpen both ways ? Now that you mention it, I've always sharpened heel-to-tip, never the other way around, and never questioned that. I'd have to look at a 101-level video from Tormek to see what they advise...

[John_B]

I sharpen heel to tip then back to heel.

I have seen people sharpen tip to heel then back to tip and the hesitation before reversing can cause a dip.

[Royale]

I used to have that happen to me quite frequently, and I discovered it was me pushing down too hard on the handle as I approached the heel. This made the knife bend slightly downwards, putting a lot more pressure on the section in front of the handle, and the corner of the grindstone, starting a recurve.

Try this experiment. Raise both your elbows up in front of you, and interlock your fingers together. You should have a straight line formed with your forearms and elbows, in front of your body, parallel to the ground.

Raise your right elbow, maintaining that straight line. You should see your forearms in a line, and start pointing towards the ground, towards your left. Rock your right elbow up and down, and this should be the motion for sharpening one side of the knife.

Keep your elbows in line with the blade when sharpening the heel section, and you have a much higher chance of keeping parallel to the grindstone. I try to keep my elbows and blade in a straight line as I go side to side, doing that rocking motion mentioned earlier.

Similar to shooting a rifle, it's a lot simpler and more consistent to reduce the moving parts (variables) on my upper body by holding the rifle the exact same way every time, and adjust with my waist and legs.

Hope that makes sense