I need tips on knife tip sharpening :-(

L

Lemarque

Joined
Jan 16, 2017
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72
I bought this large kitchen knife at the second hand store. I had to use TSPROF fillet clamps on my Toohr3 because the edge was thin and narrow; and although I did 'Sharpie" it, I ended up sharpening at 12 degrees.

Viewing the images it's obvious I munged the tip. So, my questions are, what did I do wrong and do I need to start over and remove enough material to create an entirely new edge?

https://imgur.com/a/e64ijif

and ps.
what looks like the black line is not from the sharpie
 
Something is really off. It looks like you have several different angles going on at the same time. Did you sharpie the blade and take it all off? It almost looks like only half the bevel was sharpened. How hard were your pressing? Did the clamps flex? Did you support the tip of the knife when you were sharpening it? The last picture looks like somebody raised the angle a LOT and ground on the tip for a while.

You said you sharpened it to 12 degrees, I am guessing the original angle was probably something like 20. Perhaps you just sharpened the shoulder and didn't get all the way to the apex. I would clamp it up again, fully sharpie the edge, put a pass or 2 on the blade and take a picture of what the edge looks like.
 
From the pictures, it really looks like there is two levels of grind on your knife's bevel. You claim you sharpened at 12 degrees, which is extremely shallow, so then I would interpret the the upper of the two grinds (the one further from the edge) as the new 12 degree grind. In this case it looks like you did not reach apex on the entire edge, the tip included.

Or it could be a trick of the light reflecting off of the bevel.
 
Thanks guys.

I'll re-wind and sharpie instead of shooting from the hip.

I'll also follow-up with pics of the results of the degree that I think is the correct angle.
 
Last edited:
Lemarque said:
Thanks guys.

I'll re-wind and sharpie instead of shooting from the hip.

I'll also follow-up with pics of the results of the degree that I think is the correct angle.
Click to expand...
This might help make sense, or what to look for. The top of the picture is the edge of the blade with black sharpie. The silver middle portion is where I was starting at profiling a new edge and went with a much shallower angle so the shoulder was being ground down before getting to the apex of the blade.

What you probably did was the same thing in that picture, you didn't quite make it to the edge which is why reapplying sharpie marker as you go can be really helpful.

fHS62LEh.jpg
 
I'm a firm advocate of freehanding everything. That way you will just figure it out as you go, and eventually you'll understand intuitively how to angle your passes to make a proper tip.
 
Bdtry said:
This might help make sense, or what to look for. The top of the picture is the edge of the blade with black sharpie. The silver middle portion is where I was starting at profiling a new edge and went with a much shallower angle so the shoulder was being ground down before getting to the apex of the blade.

What you probably did was the same thing in that picture, you didn't quite make it to the edge which is why reapplying sharpie marker as you go can be really helpful.

fHS62LEh.jpg
Click to expand...
Thanks very much for the follow up.

To try and clarify because sometimes my comprehension switches off ..

So I took a blade that probably had a dps of 17° and, because I felt like "let's just see what happens" and set the angle at 12°

"What you probably did was the same thing in that picture, you didn't quite make it to the edge which is why reapplying sharpie marker as you go can be really helpful."

Are you saying I should have kept at it? That is, starting with a 400 grit CBN, I moved up to a finer grit to soon?
 
David Mary said:
I'm a firm advocate of freehanding everything. That way you will just figure it out as you go, and eventually you'll understand intuitively how to angle your passes to make a proper tip.
Click to expand...
Last Xmas I got The Sharpal 162N and for some reason I just didn't feel like I knew what I was doing. I mean was I really holding a 25° angle or was it much more or less? Then I came across the Toohr and figured for a hundred dollars I'll know the angle. Which is not to say I'm anywhere near proficient 😣
 
It takes time and practice. That item looks okay, 325 grit is good for most reprofiling, except maybe large chip repair. I consider it torture to try to repair stuff like that by hand, so I just jump to the belt grinder for that stuff. I bet if you stick with that Sharpal thingy for the reprofiling side of your sharpening you'll get yourself squared away sooner than you expect, and you will thank yourself for it.

I just noticed the imgur link in your OP has multiple pics. Based on the 4th pic, in my opinion, you really just need to finish reprofiling the last half an inch or so of the tip on the left side of the blade. Jump over to the Sharpal, and scrub away at it on the 325 grit to quickly set the bevel, and then clean it up on your TSPROF.
 
Both sides of the tip could still use finishing, of course. The other thing is that blade grind itself may be a little asymmetrical, which is a common cause of seeing edge bevels like that one, in which case you would have to adjust your sharpening angle to compensate.
 
Lemarque said:
Thanks very much for the follow up.

To try and clarify because sometimes my comprehension switches off ..

So I took a blade that probably had a dps of 17° and, because I felt like "let's just see what happens" and set the angle at 12°

"What you probably did was the same thing in that picture, you didn't quite make it to the edge which is why reapplying sharpie marker as you go can be really helpful."

Are you saying I should have kept at it? That is, starting with a 400 grit CBN, I moved up to a finer grit to soon?
Click to expand...

Yes, you should have kept at it until you fully reached the edge for the entire length of the blade. Once you do that on both sides you should start feeling a burr along the entire edge. I usually start with a ~150 if I am doing a fair amount of work just to sped things up and once I get really close I switch to a higher grit stone to finish profiling and start removing scratches before moving on to high grit stones.
 
David Mary said:
It takes time and practice. That item looks okay, 325 grit is good for most reprofiling, except maybe large chip repair. I consider it torture to try to repair stuff like that by hand, so I just jump to the belt grinder for that stuff. I bet if you stick with that Sharpal thingy for the reprofiling side of your sharpening you'll get yourself squared away sooner than you expect, and you will thank yourself for it.

I just noticed the imgur link in your OP has multiple pics. Based on the 4th pic, in my opinion, you really just need to finish reprofiling the last half an inch or so of the tip on the left side of the blade. Jump over to the Sharpal, and scrub away at it on the 325 grit to quickly set the bevel, and then clean it up on your TSPROF.
Click to expand...
I'll give it a try. I can always fall back to the Toohr training wheels.
 
Bdtry said:
Yes, you should have kept at it until you fully reached the edge for the entire length of the blade. Once you do that on both sides you should start feeling a burr along the entire edge. I usually start with a ~150 if I am doing a fair amount of work just to sped things up and once I get really close I switch to a higher grit stone to finish profiling and start removing scratches before moving on to high grit stones.
Click to expand...
Got it, thanks. I'll post back, good or bad results.
 
Good luck!
 
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