What do you knifemakers use to sharpen your made knives?

B

blandies

Joined
Aug 18, 2011
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Just curious to hear what everyone uses to do the final sharpen/hone on the knives you make for customers.
Product names or links would be great.
 
What kind of differences did you see when you switched to the diamonds from what you were using before?
 
When I stopped using belts to establish the edge bevel and went to doing all of that by hand with wetted diamond stones I found that I had better edge retention, much less "wire edge" which is softened metal that has distorted away from the edge. Yes it takes a lot longer to do it, but I can hold a lot narrower (which translates to more aggressively sharp edge. I have always sharpened with flat stones, but now I establish my edge bevel and sharpen by hand on the diamond stones

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A C Richards said:
Interesting, Any references to this?
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Roman Landes introduced this in a lecture at Ashokan, and in response to someone questioning on another forum the last time I brought this up on this forum, Roman replied

Re: Unwanted Tempering Whilst Sharpening

Postby Roman Landes » Tue Sep 06, 2011 3:26 pm
Hi guys,

sorry for delay but i was out of office.


I read on another forums that Roman Landes said at ASHOKAN that he has found that sharpening a knife on a dry stone can induce unwanted tempering and lowering of the hardness in the vicinity of the edge and more so with abrasive belts.



Yes that is true.

Grinding generates energy (heat) and every step of sharpening is grinding even the strop.
This heat can be sucked away by the right coolant such as water.
If the grinding action lacks the coolant, the heat goes mostly into the torn out part and the body (blade/edge) it was torn off.
It becomes obvious to see the induced energy when you see the sparks fly (Burning steel!!).

Depending on how hard you go over the piece the more energy is induced the hotter it gets, thats basic physics.
Than the guys come and say but I can do it so sensitive that the edge will not suffer and I'm dipping the blade each run into cold water....
Well that is a nice effort, but when it comes down to the very edge this tiny fraction is overheated faster, than the eye can see or the wrinkled fingers can feel.
Unfortunately the edge becomes thinner the close you come to the very edge/point means generated heat will get jammed in the tip.
In addition to that tempering colors that would visually proof this are ground away immediately when they appear.
and Stainless steels need a higher temperature to generate tempering colors and longer time to build them up.
Nevertheless one can do metallurgical examination that can proof the issue testing micro hardness
There are some old german study's that examined this issue in the very detail.

and in a followup post Roman says:


I had a book dedicated to general grinding methods, in this book i found a test application.
A normal steel block apx. 2"x2"x4" that had a large number of highly sensitive thermocouples integrated in the surface.
The block was slit dry by hand over a 1000grit grinding paper.
The peak temps measured, walked up to 2000°C for split seconds in the very surface (some microns).
Of course the block did not melt since the volume fraction of induced heat was to tiny to affect such a large solid piece of steel.
But the effect was there and proofen.
In a edge we just talk about some microns of material, here the effect is solid an clear.
Every manufacturer of razorblades knows this and does excessive cooling whilst grinding and polishing edges, that need to hold an super sharp edge for very long.
It seems just some the magic makers out of the custom knife scene think, the physical principles like this, do not apply to them....


He has a bibliography a couple of posts later, but all of the papers and books he cites are in German. When I was working in a metallurgical lab all sample preparation had to be done with wet grinding because the heat generated from even a short dry polish would overheat the sample at the surface and destroy the structures

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Thanhs sunshadow for the info. I have blued an edge and thought about tempering effects espicially at the tip, sad thing is i use the same exact sysytem as a local factory big dog, i was taught to count draws across antler to gauge edge retention, and could see the diference only when i changed steel, great food for thought! GHaile
 
mattbrook said:
Worn out trizac belt then paper wheels
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+1 for the paper wheels. i have used them for 20 years and i have no problems with my edges from using them. some people say they ruin the edge but what do they know :rolleyes:, check out my paper wheel thread and you'll see how many pepole use and like them. the knife in this vid is on a private passaround. it was convexed on a belt sander then finished off on the paper buffing wheel. it has done quite a bit of chopping. the edge on it is still going strong http://www.youtube.com/watch?v=8q_eMwRaHYg
 
I grind my edges pretty thin, and they're no trouble to finish on a DMT diamond hone, and a 8000 grit waterstone. Final sharpening probably takes me less than 5 minutes. I like my old Lansky too. I have diamond hones and a sapphire hone that puts a mirror finish on the edge. Crazy sharp!
 
Sounds like a diamond stone is what I would prefer.
I planned on getting my knife finished, heat treated, and then when it's all done and dull with no edge put the edge/final edge on there with the diamond stone and get it sharp.

Which set from here should I consider? There seems to be quite a few choices,

http://www.theperfectedge.com/diamond.shtml
 
D6CX 6" x 2" Xtra coarse 220 grit/ Coarse 325 grit - double sided, continuous diamond $ 43.00
D6EF 6" x 2" Extra fine 1200 grit/ Fine 600 grit - double sided, continuous diamond $ 43.00

I think these two with a holder (which you could make yourself) would cover most of your needs

I'm thinking of getting one of these for doing the initial edge bevels faster
D8XX Continuous (extra coarse 120 grit) diamond on 8" x 3" x 3/8" steel plate $79.00

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I use one of these to maintain the proper angle while setting the initial edge bevels. If the blade has been flat ground to a zero edge; using a 600 grit belt on ultra slow speed; a couple of passes is all it takes. One of the major factors in producing a great edge is being able to maintain the same angle during the sharpening process. Once I have the edge set I switch to diamond stones using the same water based coolant I use on my cnc mill to flood the surface.
To keep the angle consistent while sharpening on the diamond stone, I use a set of degree wedges cut to the proper angles, to position the blade.

After the diamond I strop using leather.

Fred

bubble+jig+first+time+001_001.jpg
 
sunshadow said:
D6CX 6" x 2" Xtra coarse 220 grit/ Coarse 325 grit - double sided, continuous diamond $ 43.00
D6EF 6" x 2" Extra fine 1200 grit/ Fine 600 grit - double sided, continuous diamond $ 43.00

I think these two with a holder (which you could make yourself) would cover most of your needs

I'm thinking of getting one of these for doing the initial edge bevels faster
D8XX Continuous (extra coarse 120 grit) diamond on 8" x 3" x 3/8" steel plate $79.00

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Click to expand...

If I just got the D8XX continuous one you mentioned getting would I still need the other two? I will be doing my initial edge and finishing my edge on diamond stones alone, no belts.

Fred, I just purchased one of your nifty jigs. I look forward to using it! It seems very versatile.
 
The 120 grit is for grinding, the finer grits take you up through your final sharpening

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blandies said:
If I just got the D8XX continuous one you mentioned getting would I still need the other two? I will be doing my initial edge and finishing my edge on diamond stones alone, no belts.

Fred, I just purchased one of your nifty jigs. I look forward to using it! It seems very versatile.
Click to expand...


Give me a call any time you have a question you want to talk over. It is a very versatile little tool with many, many uses in the knife shop.

Fred
 
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