I have a ceramic knife that I use a lot but its definitely beginning to
lose its edge.

Are they worth sharpening, and if so, whats the best tool? Diamond file?
If so, what grade?

Tim


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On Wednesday, 29 January 2020 18:23:27 UTC, Tim+ wrote:
I have a ceramic knife that I use a lot but its definitely beginning to
lose its edge.

Are they worth sharpening, and if so, whats the best tool? Diamond file?
If so, what grade?

How about the finest grade of diamond grinding/polishing paste on a sheet
of glass?

I was given to understand that it was a throw away if it went blunt, but I
suppose it might be sharpened, but something hard enough and yet fine enough
to make cut smoothly could be hard to find. I wonder how they make them in
the first place?
Brian

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"Chris Hogg" wrote in message
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On 29 Jan 2020 18:23:24 GMT, Tim+ wrote:

I have a ceramic knife that I use a lot but it's definitely beginning to
lose its edge.

Are they worth sharpening, and if so, what's the best tool? Diamond file?
If so, what grade?

Ceramic knives are made of zirconia. It has a hardness of about 9.5;
diamond has a hardness of 10. You will need a diamond file, the finest
grade you can lay your hands on.

--

Chris

On Wednesday, 29 January 2020 18:23:27 UTC, Tim+ wrote:
I have a ceramic knife that I use a lot but its definitely beginning to
lose its edge.

Are they worth sharpening, and if so, whats the best tool? Diamond file?
If so, what grade?

Tim

Diamond. A set of 3 in different grits is a good plan.

On 30/01/2020 09:25, wrote:
On Wednesday, 29 January 2020 18:23:27 UTC, Tim+ wrote:
I have a ceramic knife that I use a lot but its definitely beginning to
lose its edge.

Are they worth sharpening, and if so, whats the best tool? Diamond file?
If so, what grade?

Tim

Diamond. A set of 3 in different grits is a good plan.

I'm half way between you and Chris, I'd use my double sided diamond
file, coarse side first!

Interestingly, there is a difference between "polishing" and sharpening
by grinding. As I am sure you are all aware, the Moh's scale is based on
finding one material that will actually scratch another, and I suspect
that diamond will not scratch zirconia.

But you can, actually, polish diamond with a material that is less hard.
The surface gets smoothed by a process of deformation rather than
material removal, caused at least in part by softening associated with
frictional heating. So you may be able to improve the cutting of a
ceramic knife with a softer material.

See "Bielby layer".

https://www.lehigh.edu/imi/teched/Gl...e_Lehigh .pdf

On 30/01/2020 12:49, newshound wrote:
On 30/01/2020 09:25, wrote:
On Wednesday, 29 January 2020 18:23:27 UTC, Tim+Â* wrote:
I have a ceramic knife that I use a lot but its definitely beginning to
lose its edge.

Are they worth sharpening, and if so, whats the best tool? Diamond
file?
If so, what grade?

Tim

Diamond. A set of 3 in different grits is a good plan.

I'm half way between you and Chris, I'd use my double sided diamond
file, coarse side first!

Interestingly, there is a difference between "polishing" and sharpening
by grinding. As I am sure you are all aware, the Moh's scale is based on
finding one material that will actually scratch another, and I suspect
that diamond will not scratch zirconia.

But you can, actually, polish diamond with a material that is less hard.
The surface gets smoothed by a process of deformation rather than
material removal, caused at least in part by softening associated with
frictional heating. So you may be able to improve the cutting of a
ceramic knife with a softer material.

See "Bielby layer".

https://www.lehigh.edu/imi/teched/Gl...e_Lehigh .pdf

stropping a razor?


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community, compassion, investment, security, housing...."
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"Jeremy Corbyn?"

On 30/01/2020 13:12, The Natural Philosopher wrote:
On 30/01/2020 12:49, newshound wrote:
On 30/01/2020 09:25, wrote:
On Wednesday, 29 January 2020 18:23:27 UTC, Tim+Â* wrote:
I have a ceramic knife that I use a lot but its definitely
beginning to
lose its edge.

Are they worth sharpening, and if so, whats the best tool? Diamond
file?
If so, what grade?

Tim

Diamond. A set of 3 in different grits is a good plan.

I'm half way between you and Chris, I'd use my double sided diamond
file, coarse side first!

Interestingly, there is a difference between "polishing" and
sharpening by grinding. As I am sure you are all aware, the Moh's
scale is based on finding one material that will actually scratch
another, and I suspect that diamond will not scratch zirconia.

But you can, actually, polish diamond with a material that is less
hard. The surface gets smoothed by a process of deformation rather
than material removal, caused at least in part by softening associated
with frictional heating. So you may be able to improve the cutting of
a ceramic knife with a softer material.

See "Bielby layer".

https://www.lehigh.edu/imi/teched/Gl...e_Lehigh .pdf

stropping a razor?


Yes, another good example. Another thing this is doing is removing any
little curls of swarf left by the previous process. I think that is also
one of the things behind the Ray Mears trick of finishing off a knife
blade against the edge of a car window.