Wierd shape of blade

[skärparn]

Hi! Been using T8 about 6 months. Often pleased with the results but I have one big problem. Some knifes, havent yet seen the exact pattern, gets a wierd shape of the blade after sharpening. Same problem both with KJ-140 and 45. Please see attached images. Can someone point out what Im doing wrong?

[Drilon]

Hi Skärparn,
do you sharpen by moving the knife back and forth? It seems to be the problem of the middle overgrinding.

Always sharpen from the handle to the tip.

Regards,
Drilon

[RickKrung]

Too much dwell time in that middle section?  I think it can also happen even when only going from handle to tip.  Possibly could be exacerbated by uneven pressure as the blade passes along the stone

[skärparn]

Hi Skärparn,
do you sharpen by moving the knife back and forth? It seems to be the problem of the middle overgrinding.

Always sharpen from the handle to the tip.

Regards,
Drillen

Hi, thanks for your answer!

Yes I move the knife back and forth, as seen on most instruction clips on Youtube. Do you mean I should go from handle to tip and then lift off the stone and start over by the handle side again?

//

[skärparn]

Too much dwell time in that middle section?  I think it can also happen even when only going from handle to tip.  Possibly could be exacerbated by uneven pressure as the blade passes along the stone

Thanks for your answer! That's possible, I think it's easy that you apply more pressure just where the jigg sits because you also have your hand right there. Maybe more common with long knives since more of the blade are out of the jigg. That's why I thought it might be a solution to use KJ 140 but same problem..

[Ringarn67]

This is what  Vadim (RIP) posted eight years ago.
https://forum.tormek.com/index.php?msg=16442
And there is some links in thread to even older posts from other users

Välkommen i gänget och Lycka Till 

[skärparn]

This is what  Vadim (RIP) posted eight years ago.
https://forum.tormek.com/index.php?msg=16442
And there is some links in thread to even older posts from other users

Välkommen i gänget och Lycka Till 

Thank you, I will look through that thread!

Tack så mycket

[3D Anvil]

I think it's caused by undergrinding the heel of the blade, primarily.  Paradoxically, I found I could eliminate the problem by starting at the point where the dip is, going back to the heel, and then going forward to the tip.  That way you're hitting the heel twice per pass and the rest of the blade only once.  In the alterative, just spend a little more time at the heel section.

[Dan]

Hi! Been using T8 about 6 months. Often pleased with the results but I have one big problem. Some knifes, havent yet seen the exact pattern, gets a wierd shape of the blade after sharpening. Same problem both with KJ-140 and 45. Please see attached images. Can someone point out what Im doing wrong?

I think it is quite common for many kitchen knives to have this shape already. Probably due to sharpening on a honing steel (or sharpening steel) like these
https://www.youtube.com/watch?v=B-Ko80KH3O8

Unfortunately, a lot of users use these mostly in the middle and the tip of the knife and very rarely right at the heel. Over time the knives end up like the ones in your photo.

Did you notice or check that the knives with this problem were like this before you try to sharpen them on the Tormek? You can use a straight edge or just look down carefully into the light to check.
The Tormek will not get rid of this with normal style of sharpening. You either need to spend more time on the heel as others have said and/or grind the heel part down on a grinder with coarser grit first. If you do this, be careful not to let the blade get hot.

Danny

[tgbto]

It has been mentioned in numerous other posts, but rounding out the edges of the wheel helps a lot !

[skärparn]

I think it's caused by undergrinding the heel of the blade, primarily.  Paradoxically, I found I could eliminate the problem by starting at the point where the dip is, going back to the heel, and then going forward to the tip.  That way you're hitting the heel twice per pass and the rest of the blade only once.  In the alterative, just spend a little more time at the heel section.

Thanks for your input! Will try that!

[skärparn]

Hi! Been using T8 about 6 months. Often pleased with the results but I have one big problem. Some knifes, havent yet seen the exact pattern, gets a wierd shape of the blade after sharpening. Same problem both with KJ-140 and 45. Please see attached images. Can someone point out what Im doing wrong?

I think it is quite common for many kitchen knives to have this shape already. Probably due to sharpening on a honing steel (or sharpening steel) like these
https://www.youtube.com/watch?v=B-Ko80KH3O8

Unfortunately, a lot of users use these mostly in the middle and the tip of the knife and very rarely right at the heel. Over time the knives end up like the ones in your photo.

Did you notice or check that the knives with this problem were like this before you try to sharpen them on the Tormek? You can use a straight edge or just look down carefully into the light to check.
The Tormek will not get rid of this with normal style of sharpening. You either need to spend more time on the heel as others have said and/or grind the heel part down on a grinder with coarser grit first. If you do this, be careful not to let the blade get hot.

Danny

Thank you, Im pretty sure the concave came during the grinding, and it seems to be more pronounced the more I grind, therefore something with my technique must be changed.

[skärparn]

It has been mentioned in numerous other posts, but rounding out the edges of the wheel helps a lot !

Allright, will try that!