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Bruin,
Noting your photo of the Viel belt and square, in a perfect world, everything would be plumb, square and level. With belt grinders, if the belt can be adjusted to track correctly (and stay that way) and the platen can be adjusted so that table is square to it, in my opinion, we are OK.
Ken
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That's a wealth of information for me to digest, Mark. Again I can only say thank you to you, grepper, and Ken for generously sharing your experience. I hope this thread will benefit many more people who find it.
I will order some CBN compound directly from Ken ask you suggested. Ordener's Viel mod seems like just the ticket for tracking adjustment. And that digital angle gauge is the first I've seen of the kind, thanks for the heads-up.
I kinda understand your desire to get the best edge with the least steel removal. For my wife's Japanese kitchen knives, the thought of using a belt grinder just doesn't seem right. (As an aside, I was really into cleavers several years ago. I got my wife a custom Takeda with a Super Blue core, but she actually prefers her stainless Misono gyuto. I still have a couple of CCKs and a Takeda petty. Shapton pros for all of them). The typical stainless kitchen knives will get a 150 grit edge and deburring, and maybe that's it. A major reason why I got the Viel was to do these quickly. In a strange way, belt sharpening might get me to sharpen more on stones, and hopefully I'll get better at both.
Like Ken, I'm also curious why you prefer stones to sharpening over belt grinders. Clearly you have the experience, time, and luxury to choose whatever you want. Out of curiosity, do you sharpen the knives you make on stones also?
Ken, thanks for keeping an eye out for a pyroceram. I'll try to visit some local glass shops in the coming weekends.
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One thing I have found is that when sharpening with a belt grinder only extremely light pressure is necessary. When I do it, I see very little if any belt deflection even on an open area of the belt. I let the abrasive do the work and spend little time in any one place. This generates little if any detectable heat and keeps burr to a minimum.
Using extremely light pressure may take an extra pass or two, but the results are very different than what happens if you jam the knife into the belt. Considering how much abrasive is passing the edge when using a grinder, there is no need to use much pressure. The belt will do the work.
Try just “tickling” the edge of the blade and then adjust from there depending on your results.
I use a belt grinder because it’s fast, and because I have a belt grinder it’s no problem to do a quick touch-up when needed. Knives will get dull, and for those of us who can sharpen understand that it’s really no problem to keep them sharp.
You mention that magic 150 edge number. For me at least, anything sharper for a kitchen knife is really not necessary, unless you have some special purpose use in mind. 150 is easy to obtain with a belt grinder and super fast too. I like super fast. That’s the advantage of powered sharpening.
I guess my point is to start out with as little pressure as possible. Super light pressure. And then adjust from there. Some blades take more pressure, some less, but always use as little pressure as possible. For me that was the secret of sharpening with a belt. Less is more in this case. Less pressure deforms the edge less, keeps burr formation, heat, plastic deformation and metal removal to a minimum whilst getting the job done quickly.
Grinding the edge is easy and fast with a belt grinder. For me at least, deburring while not removing tooth is far more challenging and time consuming.
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Excellent posts! Grepper, this is one of the areas (and not the only one) where your focused work really shines.
Those of you who know me also know that for the past nine years my sharpening has been primarily oriented around the Tormek. Tormek is continually evolving, both in products and in techniques. One of the evolutions in technique is using lighter grinding pressure. Modern abrasives cut better by allowing the sharp abrasives to do the cutting instead of brute force. Tormek has recently introduced five diamond grinding wheels, two in the 200mm diameter for the very specialized T2 for restaurants. (These also work very well with the T4.) Three, just introduced, are 250 mm diameter for the T7/8 size machines.
These new diamond wheels offer vast potential, however, this potential is only realized if the user learns how to use very light grinding pressure.
Grepper is cutting edge with his light pressure observations. He is a fine example of Yogi Bara's comment, "You can see a lot by looking". Grepper typifies the spirit of this exchange looking beyond basic sharpening and sharing his observations. We all benefit from people like you, Grepper. Keep up the good work.
Ken
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Sorry, that was not enough explanation. I'm so used to sharpening on Kallys that that's just where my mind goes. IMHO, 1700 SFPM is simply too fast for well controlled metal removal. I'm not dismissing belt machines for sharpening all knives. Especially if you can turn the speed down. That is by far the biggest thing.
The reason I put Mr. Grepper into a different class is because he constantly speaks of a different level of pressure than anything I've ever seen, and no one else spends nearly as much time on a belt. I know he can achieve that with a blade rest, and I'm not sure there is another way. The consistency of his BESS scores is absolutely remarkable, which I think is very significant.
Cutting belt speed by 2/3 on his Viel gives Mr. Ken very much more control. That's huge, and Mr. Ken can take it a step farther with a very low speed Tormek, and benefits from the precision of a clamped jig system. Mr. KG takes the same platform, combined with dynamic software steroids and kicks every knife out at an astounding level of precision.
I'm not even slightly concerned about anyone building heat, even with normal pressure on a Kally. By the time you're proficient on a Kally, you know how quickly worn belts build heat. It's pretty obvious when a belt has given up a sharp scratch pattern, which is before it really builds heat. No worries.
On a Kally, rate of metal removal can be devastating. You will have "oh s#$t!" moments, where a blade simply vaporizes right before your wondering eyes. With fresh, aggressive belts, it only takes a heartbeat to significantly shorten a small blade, or a soft stainless folder in particular.
"Oversharpening" is real, and far more common than not. Whenever you hear of someone dealing with a large burr, about 95% of the time it's on a belt, and totally unnecessary IMHO. It's pretty uncommon to generate a large burr on stones. Not impossible, especially on very coarse diamond stones, but it doesn't happen in two seconds like it does on a belt. Sometimes guys will think that totally removing all traces of a chip is necessary. It's not. It's Way better to remove it in due course. Just because you can take that much steel off in a few seconds on a belt doesn't mean it's best. Inexpensive knives suffer far less though.
The most insidious outcome of sharpening on a 1700 SFPM belt is the "cumulative affect" of metal removal, which is much sneakier. It involves expensive EDC knives, and it's a heart breaker. With a coarse belt, this is simply guaranteed to disappoint. I don't even think a light touch and knife rest can help.
I have a couple significant knives that were victims of the cumulative affect of high belt speed. Even with fine belts, frequent sharpening will remove a lot of blade steel over time. S30VN was kind of an unknown quantity at that time. It won't stay sharp like I prefer. In less than a couple years I suddenly realized that I'd ground away 1/3 of the blades. Using up a couple $400 blades that quickly really freaked me out.
When I'm event sharpening, I see a preponderance of inexpensive knives that probably haven't ever been sharpened, so that makes all the difference in the world.
When I set the bevels on new blades, I use a belt, but it's 2" wide and absolutely creeeeeeping. A TW90 (and Kevin's Viel, I bet) can run just fine at about 75 SFPM. That's 12X slower than a Veil, and 23X slower than a Kally, but it still only takes one minute to achieve an edge. If you spend two minutes at 75 SFPM you just wasted a bunch of steel. When you live with this on a daily basis, it's infinitely poignant.
I've approximated hand sharpening to be less than 10 SFPM. That's simply a different world for control ability. Additionally, you have a nice big patch of dead flat stone, which is not comparable to the 1" width of a belt. You really can't wobble on a stone, but it's easy to wobble on 1" of contact surface. For precision sharpening there just is no comparison.
The other things in need of consideration are the price and size of the blades. Pocket knives and neck knives have small blades. My pocket knives run from $250-$1000. Forged neck knives are $500-$1500. There simply isn't any room for error in any way.
With larger kitchen knives, it's all about precision, and the large contact area vs the small one is paramount. IMHO, you probably won't see many people sharpening Japanese kitchen knives on anything except stones. If they can't freehand, they either use guided equipment or send out for sharpening.
Many knifemakers sharpen their knives for little to nothing. I'm happy to sharpen the knives I make for free. I want them to look and perform their best. Hardly anyone can do that for themselves.
As I said, I've been sharpening on stones for several decades, and it's easy for me. Murray Carter sharpens every knife he sells by hand. So does Ed Fowler. So do most people who make or use high end knives, and anyone who uses razors, so I don't think I'm out of line in any way. Actually completely normal IMHO.
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Excellent points, Mark. Just one minor comment: When the Kally is fitted with the same Penn State Industries variable speed motor, the low speed is essentially the same as the Viel. (My Kally was a "skeleton", no motor.)
Ken
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Valuable insight on light pressure, grepper! I'll make that my mantra as I practice.
Ken, the way you speak of Tormek piques my interest. I'm going to take another look at the system, just to see how it's evolved over the last few years. And how did you get a motorless Kally? If it were readily available, I might have started with a 1SM skeleton and added my own motor and VFD. One reason I got the Viel was that I could add my own motor, but it has a larger drive wheel than the Kally.
Mark, I'm surprised at how slow you're talking about, and it makes a lot of sense. I set my VFD at 10/100 and counted about 90 rpm, which is still around 140 SFPM. It's hard to consistently dial a slower rate below that without going to zero. I'm going to play with the MIN/MAX trimpot adjustments to see if I can get more usable range on the low end. Full speed is 2710 SFPM, scary fast! I can't imagine learning to sharpen on nothing but full speed. BTW one nice thing about going overkill on a 3-phase motor size is that the torque rating is measured at full RPM; fan-cooled TEFC and open vent motors drop off to around half torque at 10% speed because of overheating.
I got in touch with Ken and ordered some CBN emulsions and linen belts. I also have some 150 Cubitrons, 80 Cubitrons IIs, and 400 Deerfos coming. I just need to get some beater practice knives, and that will keep me busy until I find a pyroceram platen.
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I experimented with my VFD and have good news for KBAC owners. You can set the maximum speed trimpot to 70, and this will give you finer speed control with the dial in the operating range. Who runs theirs at 71-100% speed anyways? Setting the minimum trimpot to about 9 o'clock lets you zero the dial and still get a usable low. Mine now runs at around 39 rpm, or 61 SFPM at the lowest speed. I found that below this, the motor no longer turns smoothly (it chugs along).
Digital VFD users, I bet you could dial in even more precision. Have fun!
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Kevin, that's what I was thinking you would find. All my VFDs act like that. In my experience, 60-80 SFPM doesn't make any difference. It's slow enough to set bevels.
I run my machines wide open too, but it doesn't matter exactly what SFPM they make. It's fast enough.
You're right about the differences between a 3 phase with VFD and... well, anything else.
The point is simply that the lowest speed gives you the most control, and if you can take advantage of the benefits of finishing an edge on high quality water stones, you'll understand why they are still popular and in very high demand.
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