Truthfully for just sharpening a cheap small belt grinder is more than good enough. Only reason I went for a better grinder than the $30 HF belt grinder is I use it for other things. But to sharpen you don't need adjustable speed water cooled or any of that other jaz.
why not sharpen on a belt grinder?
- Thread starter cap'njake
- Start date
I recently got through sharpening a set of custom kitchen knives that were previously sharpened on a powered belt sander/grinder with an extreme convex 50+ degree edge. The edges varied from moderately sharp (unused) to very blunt and dinged up.
The bevels looked good as recieved, but when put to a perfectly flat diamond stone, the extreme flaws became immediately apparent.
The bevels looked good as recieved, but when put to a perfectly flat diamond stone, the extreme flaws became immediately apparent.
Last edited:
- Joined
- Jun 4, 2010
- Messages
- 6,642
I won't use a powered grinder of any sort for sharpening without a guide. I've done so in the past and you can get pretty good at it for utility sharpening, but if multiple passes are needed it is very easy to hog off too much steel, wind up with asymmetric grinds or cosmetically chew things up.
- Joined
- Jun 4, 2010
- Messages
- 6,642
Even on a convex I use a guide. My hands/spacial abilities aren't good enough for me to hit the same angle when I make repeated passes after checking progress on any powered unit. If they were, I wouldn't take the time to jig a knife. Hat's off to those who can confidently pull that off. I normally use the grinder for commercial work or to do full regrinds, and do most of my personal sharpening by hand.
The other thing I find is that even with a jig, belt sharpening induces a slight convex. Normally I only use it to set the bevel and then move on to stones for finish work. If its utility work, I microbevel straight off the belt, and for a better effect I'll completely overgrind it with one or two stone progressions. Anything I can do to reduce angle deviation makes things go a lot quicker.
The other thing I find is that even with a jig, belt sharpening induces a slight convex. Normally I only use it to set the bevel and then move on to stones for finish work. If its utility work, I microbevel straight off the belt, and for a better effect I'll completely overgrind it with one or two stone progressions. Anything I can do to reduce angle deviation makes things go a lot quicker.
After dealing with those belt sharpened customs, it just reinforces what I already suspected.
The way I see it, you can never know what your final edge angle is, or how uniform it is sharpening on anything that gives. You may be holding the knife 15 degrees to the belt, but due to the give, pressure used, and resulting wrap around, it might actually be 25 or 30 degrees to the edge.
A belt is excellent at blending in flaws. A flat stone will reveal them.
The way I see it, you can never know what your final edge angle is, or how uniform it is sharpening on anything that gives. You may be holding the knife 15 degrees to the belt, but due to the give, pressure used, and resulting wrap around, it might actually be 25 or 30 degrees to the edge.
A belt is excellent at blending in flaws. A flat stone will reveal them.
- Joined
- Jun 4, 2010
- Messages
- 6,642
I have a system that allows me to go from the belt to the stone using the same angle of the spine to the surface. This is pretty nice as it lets me know what the amount of deviation can be at best, usually is, might be if overdone. Leaning on the belt at all will definitely add multiple degrees to the edge, more or less depending on how much surface area you're working with.
At its best you might have a degree or so - nothing more than good quality freehand. At its worst...?
That's why I use a guide. On my stone set-up I have an attachment that adds about 2.5 degrees for rapidly doing microbevels or cleaning up burrs and I will sometimes lower the angle on the belt another degree to compensate if I'm stopping at a two step edge.
If finishing on stones with a progression, I'll actually raise the belt ground edge a tiny bit to compensate - sounds contradictory, but it makes it easier to clean it all up on the stones if I'm working from shoulder to edge, especially if the blade has a coating or surface finish that highlights the stray scratches from the belt.
In practice, a degree or two is nothing and I don't fret a little here or there. I only do the extra diligence if sharpening for $ and working to a spec or told the customer beforehand they're getting a specific outcome.
At its best you might have a degree or so - nothing more than good quality freehand. At its worst...?
That's why I use a guide. On my stone set-up I have an attachment that adds about 2.5 degrees for rapidly doing microbevels or cleaning up burrs and I will sometimes lower the angle on the belt another degree to compensate if I'm stopping at a two step edge.
If finishing on stones with a progression, I'll actually raise the belt ground edge a tiny bit to compensate - sounds contradictory, but it makes it easier to clean it all up on the stones if I'm working from shoulder to edge, especially if the blade has a coating or surface finish that highlights the stray scratches from the belt.
In practice, a degree or two is nothing and I don't fret a little here or there. I only do the extra diligence if sharpening for $ and working to a spec or told the customer beforehand they're getting a specific outcome.
I applaud those that can do good work on a knife blade with powered grinding/sanding, but think it's a rarity. I've been using them all my life, even ground out a few blades, but due to my limited abilities know to stop just short of the edge and finish up on stationary abrasives.
All of these problems and complaints brought up about using power belt grinders and their faults can also be said about any and all the other sharpening methods. As I was learning to sharpen I messed up many edges with jigged systems and also bench hones. No method is full proof. You have to learn the method you want to use and in my case keep learning. A person can learn and use a belt grinder to sharpen just like any other method. There is no magic to it other than taking a little time and learning. If you want to dismiss the belt grinder as a method because you don’t want to take the time to learn it that is fine but don’t try and justify it by claiming it is a flawed system. I see many of the same arguments from the jig system crowd about free hand sharpening which is another method I prefer and use. FYI I learned how to get a sharp edge on those jig systems and know them well.
I'm no expert (and given that this is my first post, many might be tempted to completely ignore my opinions) but... at 50+ years old and having had a grandfather and father that made their own tools so that they could then use those tools to make bigger tools and workbenches, I was raised on using stones to sharpen everything. And each tool often had its own specific stone (and God help me if as a kid I used the wrong stone on the wrong tool!!). I was whupped more than once for causing irregularities in one of my Dad's stones... I still have many of them today, and consider myself pretty good with nothing more than my eyeballs, hands, and a stone on a flat surface. That being said, I sharpen a LOT of different kinds of edges - everything from spearfishing "iki jime" and shaft tips to single-edged sushi knives, folders, hunting knives, boat fillet knives, and antique Wustof/Henckles kitchen knives. They all have wildly different profiles and no one tool is "best" for them all. And I find that many new knives I buy need to be re-profiled anyway...
In addition to my carbide, diamond, and Japanese stones, I also have an Apex Edge Pro. At first I really liked the Apex but I got really tired of having to constantly flatten and replace the little stones. I also found that if I got lazy or sloppy, (or didn't have a perfectly level work surface at the right height) the results were about as inconsistent as doing it by hand. There is a running joke in my family about Dad spending entire Saturdays at the dining room table sharpening knives, and part of the reason is the lengthy process of re-profiling knives with the Apex. For this reason, I broke down and recently purchased the Ken Onion edition of the Work sharp. I love the fact that the belts never develop a "curve" that will throw off the edge profile - they just become less effective at cutting that edge. I also love how FAST I can re profile an edge when necessary.
I agree with all the comments about it being *really* easy to destroy a knife with a belt grinder/sander. But that risk is precisely the main advantage when in the hands of someone who is careful and deliberate about setup.
At this point, I rarely use the Apex any more, and only use my stones for touch-up or field maintenance when on a hunting/camping/fishing trip.
My vote is for a belt sander but with the caveat that it is better used with careful understanding of what grit belts to use and using a guide for reliable/repeatable angles.
In addition to my carbide, diamond, and Japanese stones, I also have an Apex Edge Pro. At first I really liked the Apex but I got really tired of having to constantly flatten and replace the little stones. I also found that if I got lazy or sloppy, (or didn't have a perfectly level work surface at the right height) the results were about as inconsistent as doing it by hand. There is a running joke in my family about Dad spending entire Saturdays at the dining room table sharpening knives, and part of the reason is the lengthy process of re-profiling knives with the Apex. For this reason, I broke down and recently purchased the Ken Onion edition of the Work sharp. I love the fact that the belts never develop a "curve" that will throw off the edge profile - they just become less effective at cutting that edge. I also love how FAST I can re profile an edge when necessary.
I agree with all the comments about it being *really* easy to destroy a knife with a belt grinder/sander. But that risk is precisely the main advantage when in the hands of someone who is careful and deliberate about setup.
At this point, I rarely use the Apex any more, and only use my stones for touch-up or field maintenance when on a hunting/camping/fishing trip.
My vote is for a belt sander but with the caveat that it is better used with careful understanding of what grit belts to use and using a guide for reliable/repeatable angles.
I'll say it again you can screw up a knife using any method if you don't know what your doing. I learned how to get a sharp edge on one of the jig systems and screwed up more than a few edges before I could get a good even edge.That doesn't mean that system or method is bad or worse than any other. It just means I didn't have enough time learning how to use it. You can get a knife just as sharp with a belt grinder as with anything else. There is no majic to any method other than learning it.
- Joined
- May 6, 2017
- Messages
- 45
I got a Work Sharp as a gift a while back. I can get it shaving sharp using the guided system. It took me a while to learn how to use it. On more than a few knives I took too much material off near the heel using too much pressure. It's really easy to screw up a blade, so much that I won't sharpen other peoples knives, I've had a friend or two ask.
My most expensive blade is a Delica, but I've been looking at getting a better sharpening system before I spend my money on more expensive knives.
My most expensive blade is a Delica, but I've been looking at getting a better sharpening system before I spend my money on more expensive knives.
Once you learn and understand the basics of sharpening you should be able to get a good edge useing just about anything. Watch Murray Carter get a good edge off of a cinder block and cardboard. Now I wouldn't really recommend using any kind of powered sharpener before learning the basics but once you have masterd sharpening they are a great tool to use.
- Joined
- Dec 27, 2004
- Messages
- 2,270
If you have the Ken Onion version... add the Blade Grinding Attachment. Night and day difference in the control you have, that'll equal better results.
- Joined
- May 6, 2017
- Messages
- 45
Just the regular Work Sharp. My dad gave it to me for Christmas probably 5 years ago. I just got into knives seriously and have been trying my hand at it.
He can get his blades scary sharp with it but I suspect he may be doing something different.
I've been looking at the KME as my next sharpener.