Chef knife edge thickness before sharpen..

M

Moz Blade

Joined
Oct 30, 2021
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14
I am finding it difficult thinning my chef knifes edge down to the final thickness before sharpening. I’m also struggling with getting the edge thickness even over the whole blade length. How thin should I thin my edges before sharpening? I’m using mostly 5160 (I know not the best) and I am just starting out with 52100.

I find that when I use a lansky sharping system the bevel looks a little wavy. I’m pretty sure that that’s because the edge isn’t the same thickness.

Thanks
 
What are you grinding with? files or 2X72 grinder? What equip do you have to work with?
 
Almost sharp edge kinda thin.

If you have a grinder this is easily achievable but if your just working with hand tools, your edge is probably only going to be as thin as it is before you HT.


IMG_3189.jpg
 
These days i come off of the 60 grit belt with the edge between 0.007" and 0.009". When i go to the 120 grit belt i am really mostly removing scratches and refining the bevel/shinogi transition, but there is some metal removal at the edge that brings it down to something like 0.004-0.005". I usually call it quits there, and the rest of my belt work is surface finish refining. I find if i try to go thinner my risk of biting into the edge proper (and thus grinding it back) goes up a lot.

As to "how" ... i find i have developed something for a feel for visual recognition on when i am getting down into that range and also for how the thickness varies along the length of the edge, but when i am almost there i rely on my calipers to measure the edge at several locations along the edge. I then concentrate on those thicker locations (slower belt speed, lighter pressure) to thin just those areas...
 
Diego_B said:
Almost sharp edge kinda thin.

If you have a grinder this is easily achievable but if your just working with hand tools, your edge is probably only going to be as thin as it is before you HT.


View attachment 1780524
Click to expand...
I have a 2 by 72. But Im finding it touch to get the edges consistent thickness.. but I have only had it 5 months. So I’m sure much more practice is needed.
 
Cushing H. said:
These days i come off of the 60 grit belt with the edge between 0.007" and 0.009". When i go to the 120 grit belt i am really mostly removing scratches and refining the bevel/shinogi transition, but there is some metal removal at the edge that brings it down to something like 0.004-0.005". I usually call it quits there, and the rest of my belt work is surface finish refining. I find if i try to go thinner my risk of biting into the edge proper (and thus grinding it back) goes up a lot.

As to "how" ... i find i have developed something for a feel for visual recognition on when i am getting down into that range and also for how the thickness varies along the length of the edge, but when i am almost there i rely on my calipers to measure the edge at several locations along the edge. I then concentrate on those thicker locations (slower belt speed, lighter pressure) to thin just those areas...
Click to expand...
Makes sense thanks. I just need to practise more. I just got a wet grinding set up and that helps me slow things down and watch the edge closely as im grinding.
 
Moz Blade said:
I have a 2 by 72. But Im finding it touch to get the edges consistent thickness.. but I have only had it 5 months. So I’m sure much more practice is needed.
Click to expand...
If you are having trouble keeping your edges even along the whole edge it sounds like you aren't getting a good initial grind to begin with? I use a block cut at a 45 degree angle to use as a guide to know off the 45's and get my center line established. On forged blades this is a little more difficult to do since your edge is already fairly thin if you forged your rough bevels but using a guide has helped me a lot. Then once I get to that point where I am satisfied and still leaving some meat on the edge I grind my bevels with sweeping motions across the whole blade.
 
I usually finish my blades with lengthwise grinding. Really does a good job of keeping the bevels smooth Take a look at Nathan's setup here:

Lengthwise grinding, plunge grinding, compound curvature platen. Very cool.

I am an evil super genius. This is the best idea ever. This is a platen I made with compound curvature for finish grinding a hollow ground blade lengthwise. I've been wanting one of these for a while so I finally made one and put it in my last batch of platens. It came back from Peter's HT...
www.bladeforums.com www.bladeforums.com
I don't have his same setup, just something I rigged up myself, but it works nicely.
 
Ken H> said:
I usually finish my blades with lengthwise grinding. Really does a good job of keeping the bevels smooth Take a look at Nathan's setup here:

Lengthwise grinding, plunge grinding, compound curvature platen. Very cool.

I am an evil super genius. This is the best idea ever. This is a platen I made with compound curvature for finish grinding a hollow ground blade lengthwise. I've been wanting one of these for a while so I finally made one and put it in my last batch of platens. It came back from Peter's HT...
www.bladeforums.com www.bladeforums.com
I don't have his same setup, just something I rigged up myself, but it works nicely.
Click to expand...
Every time I have tried lengthwise grinding I have damaged my edge line. Just one reference point…
 
You dont really need to put whole edge down when grinding lengthwise. Rotate your blade to put more surface down on the platen. I usually tilt down the heel of the knife. When evening the thickness and flatness of the grind I usually notice that my tip and heel are thicker. Switching the orientation even a bit will show you fast where the blade is thicker. Basically the same thing that N Wheeler recommends in his hand sanding video just on the grinder. Other option is grinding lengthwise on the wheel, but that takes even more practice IMHO.
 
When I grind a blade and the grind is "finished" but the edge is a bit to thick I simply tilt the blade more and thin down the edge and then walk, from the new edge, back up into the grind.
 
AVigil said:
When I grind a blade and the grind is "finished" but the edge is a bit to thick I simply tilt the blade more and thin down the edge and then walk, from the new edge, back up into the grind.
Click to expand...
That is another approach that has caused me problems with digging into the edge. Much safer to keep the belt on the flat, and work it down on that angle until the edge gets to the thickness I want
 
AVigil said:
When I grind a blade and the grind is "finished" but the edge is a bit to thick I simply tilt the blade more and thin down the edge and then walk, from the new edge, back up into the grind.
Click to expand...
That actually makes a lot of sense. I’m going to give that a try next. Thanks
 
Does your grinder have a vfd? Turn the speed way down. Or use a diamond stone. You can also slack bring the last few thou for a slight convex for a bit of food release.
 
Cushing H. said:
That is another approach that has caused me problems with digging into the edge. Much safer to keep the belt on the flat, and work it down on that angle until the edge gets to the thickness I want
Click to expand...
Sure you can do it that way, but at the final stages of grinding and the edge getting thinner you are generating a lot of heat with full blade contact on the belt which in an instant can burn the edge.

That is why some makers wet grind to avoid that.

With the technique I described you have much less heat build up at the edge
 
Cushing H. said:
These days i come off of the 60 grit belt with the edge between 0.007" and 0.009". When i go to the 120 grit belt i am really mostly removing scratches and refining the bevel/shinogi transition, but there is some metal removal at the edge that brings it down to something like 0.004-0.005". I usually call it quits there, and the rest of my belt work is surface finish refining. I find if i try to go thinner my risk of biting into the edge proper (and thus grinding it back) goes up a lot.

As to "how" ... i find i have developed something for a feel for visual recognition on when i am getting down into that range and also for how the thickness varies along the length of the edge, but when i am almost there i rely on my calipers to measure the edge at several locations along the edge. I then concentrate on those thicker locations (slower belt speed, lighter pressure) to thin just those areas...
Click to expand...
I do the exact same thing. I might add that I grind with 120 almost parallel to the platten rather than perpendicular to make sure to remove all 60 grit scratches. This also helps even up the edge.
 
AVigil said:
Sure you can do it that way, but at the final stages of grinding and the edge getting thinner you are generating a lot of heat with full blade contact on the belt which in an instant can burn the edge.

That is why some makers wet grind to avoid that.

With the technique I described you have much less heat build up at the edge
Click to expand...
Actually, i find heat to be much less of an issue doing it that way. There is more mass of metal in the bulk of the blade to absorb heat, and most of the grinding is actually away from the edge itself. Also, you can actually see (looking down at the gap between the edge and the belt) as the grinding "interface" approaches the edge proper, and adjust as necessary to avoid digging into the end of the edge
 
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