Reprofiling a wide factory edge angle. Your approach?

S

Shnipper

Joined
Jul 26, 2020
Messages
7
Hi everyone!

Questions first:
- If you are sharpening a knife for the first time and the factory edge angle is too wide, for your liking, with which stone do you usually start with, and why do you like that stone?
- I find the Cerax 320 too slow for reprofiling, which stone would you recommend as a significant upgrade in terms of speed?
- Does it make sense to get a Naniwa Traditional 220 or is the difference to the Cerax 320 too small?


I recently started freehand sharpening my knives. I sharpened 9 knives so far and got another dozen lying around (old German and Swiss knives like Zwilling, Wüsthof, Rösle, Victorinox), that are so dull that they are used as cake knives at this point. Many of them have a factory edge angle of 40 degree or more, inclusive (and sometimes uneven).

I sharpen most of my knives to 30 degree inclusive. The right side usually 13-14 degree and the left side 16-17 degree. That just seems the most comfortable position for my hand when I sharpen.

I have trouble holding that steep 20 degree factory edge while sharpening and getting the bevel to 13-14 degree always takes a long time (30-40 minutes for one side). I use light pressure (1-2 pounds, 3-4 pounds max only at the beginning), with a back and forth motion over the stone and I move along the blade in sections. If a stone isn't fast enough while trying to raise a burr, I much rather go to a lower grit stone than using higher pressure on the current stone.


My stones: Cerax 320 (model 401), Bearmoo (probably same as Sharp Pebble) 400/1000, Naniwa Economical combi 1000/3000, Shapton Pro 2000;

The Cerax kinda feels like the Sharp Pebble 400 but is a bit faster I think.
 
unless the thickness behind the edge was pretty thin i would start with my coursest stone(i sometimes start with a grinder and finish with a stone to prevent overheating) and put the primary bevel(not to bevel that forms the edge) flat on the stone and grind it until i just barely feel a bur and then switch to the other side and polish until i get the desired finish at which point put the actual edge on with a few strokes of my finest stone(a hard black arkansas stone) at the desired angle and maintain it using said stone but that is because i prefer to be really thin behind the edge and find this method to be the easiest way to get my prefered edge geometry and i find that the edge angle is less important so long as it is above 10 degrees inclusive and it is thin enough behind the edge ymmv.
 
The best stone I've found for thinning out a thick edge, and behind the edge, is the 60 grit Baryonyx Manticore. From what I read when I first started sharpening, I thought ~120 grit stones (mostly SiC and diamond) would do the job well. I like this grit but it's too slow for me when it comes to quickly hogging off metal, especially with my thicker, hard-use outdoor knives. I use the Manticore for probably 90% of my sharpening. The rest is just light finishing strokes at higher grits for coarse, toothy edges.

I also like my edges to be thin as well as sharp. I don't pay much attention to following factory edge angles as most of them are too thick for me, from what I've seen. I relief grind as described in The Razor Edge Book of Sharpening. If an edge rolls or chips for what I need it to do I'll put on a temporary microbevel and sharpen at a slightly higher angle next time until I get it right.
 
DMT works well when you use a light touch. If you have a naturally heavy hand at higher grits, SiC are a good option. You aren't tearing the diamonds out of the matrix, but exposing a fresh layer of abrasives.

I guess it depends on your technique.
 
I’ve used my bog standard belt sand to good success clamped in a vice, although getting close to the heel can be an issue
 
If you have a diamond flattening stone, use that unless you are heavy handed.
Otherwise at least a 120 if you are talking water stones or a coarse SiC.
I mean you can do it with that 320, it's just a question of how much time you want to put into this - or money to shorted the work.

I've done something similar with a soft 320 and at up 1/4 the stone.
 
Yes, ^ a diamond flattening plate would be better. Which are more coarse than a x-coarse and are recommended for such work. I used my x- coarse to do that once 220 grit,and leaned on it. Which didn't turnout well. DM
 
I can get a 6x2 double sided DMT (coarse / extra-coarse) for 55€. Diamond plates seem very polarizing - people either hate them or love them. I don't have a diamond plate, yet, so I don't know on which side I fall.
I looked for the Baryonyx Manticore but it's hard to get outside the US.

I ordered an 80 grit Norton Crystolon for 22€ now. Maybe I will try the diamond plates some other time.
 
David Martin said:
Use the 80 grit. It will do the job. Then progress finer. DM
Click to expand...

Is the 80 grit Norton stone a rubbing brick? I looked it up but it didn't give a grit rating. I thought 120 was as low as Norton went with their Crystolon series.

If it is a rubbing brick, do you use a lubricant? Thanks...

Shnipper, I use diamond plates for light finishing strokes only. The instructions usually say to only use light pressure with diamonds, but I can remove metal significantly faster using SiC stones with heavier pressure. My guess is that most of the problems people have with diamond plates is because they don't follow the instructions and use too much pressure.
 
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MtnHawk1 said:
Is the 80 grit Norton stone a rubbing brick? I looked it up but it didn't give a grit rating. I thought 120 was as low as Norton went with their Crystolon series.

If it is a rubbing brick, do you use a lubricant? Thanks...

Shnipper, I use diamond plates for light finishing strokes only. The instructions usually say to only use light pressure with diamonds, but I can remove metal significantly faster using SiC stones with heavier pressure. My guess is that most of the problems people have with diamond plates is because they don't follow the instructions and use too much pressure.
Click to expand...

It's the Norton Crystolon fine/coarse stone. On some sites it says 80 grit and on some sites it says 100 grit so I am not 100% sure which is correct. And it says it can be used with water but I'll probably use oil or an oil-dishsoap-water mixture. What is a rubbing brick?
I probably wouldn't have that problem with diamont plates because I like to use light pressure anyway.
 
David Martin said:
Mountain Hawk, you looked this up before. Its the Ace stone in SiC grit. DM
Click to expand...

My question was regarding an 80 grit Norton stone. Since this was mentioned in the post immediately preceding your Post 11, I naturally assumed this was the "80 grit" you were referring to in Post 11.

I can't read minds so I had no idea you were apparently referring to something in an old, unrelated thread.

Shnipper, the Norton Crystolon Coarse stone is 120 grit and the Fine is 320, so I was puzzled when you mentioned an 80 grit Crystolon (Post 10), which I've never heard of. I have a rubbing brick in 60/80 grit, which is why I thought your "80 grit Crystolon" might instead be a rubbing brick, which Norton also makes.

A rubbing brick is a low-grit abrasive used to smooth and clean hard surfaces, such as concrete.
 
Yes, they are not easy to find. They were offered and bought up. I doubt some don't know what they have. I was able to get a 6 and 8". DM
 
jpm2, I don't believe I've ever seen an Ace 80 grit stone, either.

There aren't many manufacturers that come to mind when I think of SiC or AlOx stones lower than 120 grit. That's why I was happy to find the 60 grit Manticore, and to have confidence in its quality and consistency. It's just what I needed.
 
David Martin said:
Yes, they are not easy to find. They were offered and bought up. I doubt some don't know what they have. I was able to get a 6 and 8". DM
Click to expand...
Were these combos, or single grit?

MtnHawk1 said:
jpm2, I don't believe I've ever seen an Ace 80 grit stone, either.

There aren't many manufacturers that come to mind when I think of SiC or AlOx stones lower than 120 grit. That's why I was happy to find the 60 grit Manticore, and to have confidence in its quality and consistency. It's just what I needed.
Click to expand...
Been meaning to pick up a manticore. In the meantime I still have a couple norton jb8's and 6's, my previous job kept us stocked with them.
 
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