"Dishing" or frowney face curve in blade

[polo_gratitude278]

Hi,

I have run into an issue when sharpening with my T8. Let me start by saying that I am new to sharpening with the tormek. Ive watched a ton of videos on setup and technique. When I sharpen my kitchen knives I have been grinding out a curve that is around the last 1/3 of the blade (closest to the handle).Ive gotten pretty good at doing it consistently and I cant figure out where I am going wrong. My general procedure is to set the angle then I start by placing the handle side of the blade on the stone, then moving to the tip, I then pick the blade up and start back at the handle side, I usually, alternate sides 1:1 or 2:2.

I have not found any videos addressing this particular problem, any suggestions would be appreciated.

Thanks!

Steve

[Royale]

From my personal experience:

1. When I used the T-8 standing behind it, I used to have the bad habit of resting my hands on the knife, with more pressure on the handle. This often made the blade "see-saw" across the grindstone, as well as applying uneven pressure during sharpening. This would often cause gouges along the blade, and uneven sharpening near the heel/tip of the knife.

2. I also used to speed up moving the blade across the grindstone when starting from the heel and finishing at the tip. This often created slow areas of progress along these two spots.

What I do now:

a. Instead of standing behind my T-8, I sit in front of it with an LED lamp overhead, shining directly onto the grindstone. This broke my habit of resting my hand on the knife handle, and I could see very clearly when the knife began to "see-saw". This also allowed be to monitor the water that gathered in front of the blade, and really helped me start with the heel of the knife fully squared against the grindstone.

But in summation, maybe look closer at how you've been applying pressure as the knife moves across the grindstone, and develop a setup that works best for your work environment and body.

[polo_gratitude278]

Thanks the body positioning is something I haven't considered.

[BPalv]

From my personal experience:

1. When I used the T-8 standing behind it, I used to have the bad habit of resting my hands on the knife, with more pressure on the handle. This often made the blade "see-saw" across the grindstone, as well as applying uneven pressure during sharpening. This would often cause gouges along the blade, and uneven sharpening near the heel/tip of the knife.

2. I also used to speed up moving the blade across the grindstone when starting from the heel and finishing at the tip. This often created slow areas of progress along these two spots.

What I do now:

a. Instead of standing behind my T-8, I sit in front of it with an LED lamp overhead, shining directly onto the grindstone. This broke my habit of resting my hand on the knife handle, and I could see very clearly when the knife began to "see-saw". This also allowed be to monitor the water that gathered in front of the blade, and really helped me start with the heel of the knife fully squared against the grindstone.

But in summation, maybe look closer at how you've been applying pressure as the knife moves across the grindstone, and develop a setup that works best for your work environment and body.

I just can't picture sitting in front of it... How tall is your stand and chair?  Do you grind edge leading?

[Royale]

I'm using a regular chair meant for a dining table, but my work table is set quite low. So that puts the contact point between the blade & grindstone at about eye level.

My T-8 is also positioned quite close to the edge of my work table, and I sit with the grindstone in line with the centre of my body.

I sharpen edge leading while seated, but I stand up while honing and sharpening edge trailing.

[RickKrung]

I just can't picture sitting in front of it... How tall is your stand and chair?  Do you grind edge leading?

I'm using a regular chair meant for a dining table, but my work table is set quite low. So that puts the contact point between the blade & grindstone at about eye level.

My T-8 is also positioned quite close to the edge of my work table, and I sit with the grindstone in line with the centre of my body.

I sharpen edge leading while seated, but I stand up while honing and sharpening edge trailing.

I've been sitting in front of my T8 almost since getting it eight years ago.  I have neuropathy in my legs and cannot stand very long before it becoming too painful.  I sit in a castered, swivel chair and my T8 is on a standard height folding table (30"). I sharpen knives almost exclusively edge-leading, so my hands wrap around and hold the jig on the vertical USB. 

For a while, I tried using a short stool (18") as the workstand for the T8l, sitting on the same swivel chair.  It worked well enough and may have been a bit more comfortable as my hands didn't have to bend as much.  However, there wasn't convenient enough workspace adjacent on both sides for efficient workflow. 

I do stand when working edge trailing, most particularly when using the drill bit jig (DBS-22) and the angle of view isn't suitable, nor is it comfortable or effective.  However, when using the SJ wheel for polishing knives, which many say should only be used edge-trailing, I do use the SJ edge leading in the same sitting position as other grinding and honing wheels.  I've never really had any problems with the SJ wheel catching, which is the reason some say it should be used edge-trailing

Rick

[Stovepipe]

Rick,
I noticed your using a laser to mark the proper angle that you've set or determined for the knife. Where did you get the holder and laser to mount on the USB? I very much like your approach.

[RickKrung]

Rick,
I noticed your using a laser to mark the proper angle that you've set or determined for the knife. Where did you get the holder and laser to mount on the USB? I very much like your approach.

I believe use of a laser line module was started by Wootz, of Knife Grinders.  I did a search here on the search string "laser line module" and found an early, but not the first reference to it.  There was the exact same question asked in this thread.  The laser line module itself I bought off Amazon.  Lots of options out there, key being the projected "line".  I made the holder and after seeing it in one of the forum posts, Wootz commissioned me to make a multi-laser holder for him, but I think he just used it, never made any for sale.

I think a more broad search on just "laser", "laser line" or "laser module" would turn up more discussion on this.  There was a lot back in the day. 

I have to say that the laser helped initially.  The concept is to help maintian the "line of contact" (LOC) of the bevel with the grindstones.  However, it quit working and I have not bothered to replace it, having learned to hold the position by eye.  Searching on "line of contact" also brings up a lot of discussions. 

Rick

[Stovepipe]

Thank you for the reply and photos. I've been wondering how people do freehand and maintain any accuracy when sharpening. I started thinking (probably the wrong thing to do at my age) the difference between angle when it comes to the contact point on the wheel. Assuming your holding the blade flat and parallel to the ground the contact point between angles is damn small, as in ~2.2 mm per deg. I cut out a piece of wood to and marked where the 13°, 15°, 16° and 17° contact points would be. I must say, you have to have one helluva muscle memory control to hold the line. Sometime I just need to look at the big picture and remind myself, I'm just after a sharp knife to cut the vegetables, fish and meat.

[Stovepipe]

here's the photo

[3D Anvil]

Schleifjunkies sells a line laser and holder for Tormek.