Trying to sharpen on my whetstone but do not get a burr ...

M

Mikali

Joined
Sep 15, 2014
Messages
23
Hi guys,

I'm fairly new to the hobby (my knife obsession started with straight razors) and am now moving on to pocket knives as well :)
Now I just followed a workshop of whetstone sharpening, and at the class itself it worked quite well on my kitchen knives.
However now, back at home, I have difficulties raising a "feelable" burr on my pocket knife (brandless).
I've counted my strokes and after 120 I gave up ...
Thought it was my technique or so but when I tried my kitchen knife again I raised a burr in about 20 strokes ... (european knife, at 20°degree angle)

What do you think? should I be more patient and keep on doing strokes, or is the quality of the brandless pocket knife that bad it is hardly possible to sharpen on a whetstone?

thanks in advance, and hope to learn a lot here on the forum ;-)
 
How long it takes to form a burr depends on how much metal you have to remove to reach the apex of the edge. The kitchen knife was likely thinner behind the edge than the pocket knife. Inspect the area you're sharpening visually from time to time to see how far you've come. If you're not all the way up to the edge yet, keep scrubbing (alternating sides once in a while to keep it even).

If you're having a hard time seeing what part you're sharpening, you can colour the edge with a permanent marker to make it easier to see what part the stone is coming in contact with.
 
Thanks mrdeus for the reply :)

Just went to buy a Opinel no8 to test my sharpening "skills" on and while at the office I dulled it and then re-sharpened it with coffee mug and afterwards stropped it on my leather belt.
Guess what, it's very sharp and cuts paper like it's nothing ...

So to go back on-topic with the cheap brandless knives, could this be the reason why they are so hard to sharpen ? or is the ceramic side of a coffee mug a lot coarser then a 600 grit carburandum stone ?
 
The bottom of a coffee mug is simply a poor choice of tools. It is nowhere close to having a uniform grit structure and if it's improving your results over what a quality stone can do then your tools are not to blame.

Giving up and trying other methods are the biggest mistake that beginners make. Another one is using low quality stones, while some may "work" they are a far cry from the results a quality stone will yield.
 
Mikali said:
Thanks mrdeus for the reply :)

Just went to buy a Opinel no8 to test my sharpening "skills" on and while at the office I dulled it and then re-sharpened it with coffee mug and afterwards stropped it on my leather belt.
Guess what, it's very sharp and cuts paper like it's nothing ...

So to go back on-topic with the cheap brandless knives, could this be the reason why they are so hard to sharpen ? or is the ceramic side of a coffee mug a lot coarser then a 600 grit carburandum stone ?
Click to expand...

Sometimes one can have problems with the stone, if your carborundum is choked up or glazed it won't grind worth a bean. Also, on fairly aggressive man-made stones, the softer steels can actually be more challenging if you're not used to it. I just responded to another thread re how well the coffecup can work on lower RC steel, can be a better tool for the job than a more effective abrasive sometimes - similar to how many do not care for diamond on carbon steels. It works but is not the best tool for the job in many cases.
 
Mikali said:
Thanks mrdeus for the reply :)

Just went to buy a Opinel no8 to test my sharpening "skills" on and while at the office I dulled it and then re-sharpened it with coffee mug and afterwards stropped it on my leather belt.
Guess what, it's very sharp and cuts paper like it's nothing ...

So to go back on-topic with the cheap brandless knives, could this be the reason why they are so hard to sharpen ? or is the ceramic side of a coffee mug a lot coarser then a 600 grit carburandum stone ?
Click to expand...

Too many unknowns; both with the steel, and the tool used. With 'cheap' steels like these, it's best to at least start with a sharpening tool that's predictable and reliable and known to work well for actual sharpening. A 'ceramic' coffee mug, by it's very origin, is simply pottery (meaning of the word 'ceramic'); it's made according to a 'pottery' process, but the base materials are usually a complete unknown. As mentioned, it's made with materials that really weren't ever intended for sharpening, and so will be widely variable in use. Sometimes you get lucky and find one that works well with a given blade; but even that takes time and also requires adapting the technique to it (stroke, pressure, etc.).

'Cheap' steels are usually at least low in carbon, and probably high in chromium (assuming stainless). It's also likely they weren't tightly controlled in heat treat. All of these things in combination mean the steel will at least be 'soft', and less likely to support a fine edge. Heat treat issues can also introduce larger grain, which also makes a steel less likely to take a refined edge in the first place. With steels like this, usually 'simpler and coarser' is the best route in sharpening. An aggressive hone in diamond, AlOx or SiC, used with very light pressure, will usually leave at least a serviceable utility edge on them. Trying to refine further, or take it to a high polish, is usually unrewarding. Either the steel will end up with a very fine edge which quickly folds over, or the edge won't refine beyond a certain finish without just crumbling away at the first cut. On the other hand, a known good steel from a reputable maker (like Opinel) can respond very well to a very wide range of sharpening tools, with minimal effort. Good heat treat, minimal impurities and fine grain make the difference.

I'd avoid using the coffee mug for this blade, and at least start out with a known good stone. The 600-grit carborundum might work, and I'd even suggest something coarser, such as down to 320/220 or so for blades like these. If your stone is clogged or otherwise not working well, some wet/dry sandpaper used over the top of it could provide the fresh grit, and should work up a burr pretty fast.


David
 
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Cheap blades often come ground really, really badly. It's normal to see a very thick blade with an obtuse edge (big angle) that's not really even fully ground to an apex. You should absolutely use the sharpie technique and see if your angle is matching what's already there, or if you're just grinding away at the shoulder (which would not be unusual). Second, you should look straight down at the cutting edge and see if it reflects light. If so, that's the issue: It's just very dull and you haven't made the two edge bevels meet in the middle yet.

Let us know how you do.

Brian.
 
Get Sanrenmu, or Enlan. They're cheap enough but the heat treat is adequate to support 30 degree inclusive. Good enough to learn sharpening and serve as EDC.
 
You should give a coarse silicon carbide stone a try. 600 grit is intermediate or even final sharpening depending on fineness preferences.
 
@yepinmonfire
Fyi, carborundum = silicon carbide :) (just found that one out myself haha)
However is it maybe an idea to rather buy a diamond stone with a grid of lets say around 320 ??
 
Mikali said:
@yepinmonfire
Fyi, carborundum = silicon carbide :) (just found that one out myself haha)
However is it maybe an idea to rather buy a diamond stone with a grid of lets say around 320 ??
Click to expand...

You could, if you really think you want the diamond. For the blade you're sharpening, you likely don't need diamond. A coarser SiC ('carborundum') stone can be found at Home Depot (the Norton 'Economy' stone) or Ace Hardware (essentially identical to the Norton Economy stone, under Ace's own branding). Either could work just as well, and you likely won't spend more than about $7-$8. Both are double-sided and rated 'Coarse/Fine', and the 'Fine' side will be close to the 320-grit you're looking for; the 'Coarse' side is something around ~120-grit. I have one of the Norton Economy stones, and it's very well-suited to blades like these; I use the 'Fine' side almost exclusively.


David
 
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I should mention I plan to buy a knife with harder steel like s30v in the near future ... But still, i doubt between a DTM or naniwa coarse stone ...
 
I have ordered a Shapton pro 320 grit and 1000 grit stone together with a DMT extra coarse for flattening the stones.
Those should be able to complement with my Cotcarb (Carborundum and BBW) and Coticule to get the hang of the "art" of sharpening :-)
 
Mikali said:
I have ordered a Shapton pro 320 grit and 1000 grit stone together with a DMT extra coarse for flattening the stones.
Those should be able to complement with my Cotcarb (Carborundum and BBW) and Coticule to get the hang of the "art" of sharpening :-)
Click to expand...

Nice choice of stones!
 
Try black magic marker to see where you are contacting the bevel when sharpening.
One other note, kitchen knives are somewhat easier to sharpen because of the size of the knife. Easier to hold stable and have nice even stroke across the stone surface. Pocket knifes are more challenging in that respect.
 
Are you sure you are not getting a burr? Its not as obvious on heavier blades as it is on kitchen knives in my experience.
 
I've been trying to sharpen again and got my Opinel no8 to cut paper fairly easy so I'm going into the right direction BUT.
When I tried the same on my small Swiss knife on an angel of 20 degrees I stays dull ... Have been looking at it, feeling it, but no clue what's wrong.
What I would like to know is when you finish with the coarsest stone, the knife should already be sharp right? But sharp enough to cut sponge or paper?
Just for me to know whether it is the angle that's not right, or I go to the finer grit to quickly :)
 
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