# Interesting sharpening video by J. Nielsen



## gic (Jun 1, 2016)

I was googling J. Nielsen (the forged in fire guy) and discovered two interesting sharpening videos by him made 6 years apart

[video=youtube;TLjFjT4vYsM]https://www.youtube.com/watch?v=TLjFjT4vYsM[/video]

[video=youtube;3KShdBL_1Og]https://www.youtube.com/watch?v=3KShdBL_1Og[/video]

Noteworthy is that he uses only a low grit belt and a stropping belt. But the speed at which he claims he can sharpen and the edges he claims to get are pretty mindboggling. 

(Also he still seems to be using what looks like the same (slack belt) 1x42 belt sander from Kalamazoo in both videos which says a lot about the durability of that unit if true)

Do people believe he can get that good an edge with only the single 220 grit belt and a stropping belt with compound? He is a master smith of course, so he obviously is no slouch at stuff.

Does anyone else use a 1x42 slack belt grinder for sharpening?? (In addition to the Kalamazoo version there is a version from Viel that I found by googling).


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## Kippington (Jun 2, 2016)

Do I believe he can get that good an edge with only the single 220 grit belt and a stropping belt with compound? Absolutely. It seems pretty standard to me, but then again I use belts quite often (although nowhere near as often is some of the vendors on this forum).

His methods are sound, and his 2 minute claim is well within reasonable limits for a knife that has been well maintained.

I use a very cheap belt grinder that has a slack area. He mentions in the video that a cheap grinder will work well for maintaining an edge, more expensive grinders are better for saving time for people that do this for a living. He talks about pressure and slack behaviour, but that will depend on your set up. He also makes it very clear what kind of edge geometry he is trying to achieve.

What exactly is so hard to believe about these vdeos?


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## gic (Jun 2, 2016)

Oh don't get me wrong, I found the videos very interesting and informative. But I compare it to the number of grits I use when I do a full sharpening via stones so two belts is a lot less than 4 or 5 stones to bring a knife back from the dead (say 220, 400, 1000, 3000 and a natural finishing stone) -) )


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## ecchef (Jun 2, 2016)

Well, he's not finishing precision kitchen knives here. For a hunter, utility, fighter, or even a butcher knife like he's demo'ing this procedure is probably good enough. 
Yeah, it's 'sharp', but he's not getting the same results that you would with a stone progression.


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## rogue108 (Jun 2, 2016)

I am speculating but I believe the success to this process is the power strop on a loaded leather belt. I had Dave sharpen a brand new Chinese Shabazi cleaver using a rough grit belt followed by stropping on a bench grinder with a leather wheel loaded with Chromium Oxide. It took less than 5 mins, he set a nice bevel on the belt and the leather wheel took care of the rest. It had a nice toothy edge and I didn't feel like it needed to hit the stones until a month had passed with home use but I did strop weekly on felt (forget if it was loaded or not). 

Another testament to the leather power strop is the individual who I bought my DT ITK from. It had a wicked edge so I asked what he did to get it and the answer was finishing on a medium JNAT then stropping on a 1x42 with a CrOx loaded leather belt. Again, I am speculating but I believe its the speed at which the grinding and stropping is taking place. You can for the most part raise a burr in seconds on a belt sander and rip it off in seconds on the leather belt while the edge is getting refined.

Precision, no. Effective, yes


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## Kippington (Jun 2, 2016)

By skipping the medium to fine grits he's creating a toothy edge with polished ends. There are some old posts floating around here and many other forums too that talk about this in more detail. It's worth experimenting with just to see how it changers the behavior and lifespan of a more refined finish.
Coarser finishes can be quite effective for some kitchen knife applications, and the edge stays sharper for longer then a full polished edge. I think someone on this forum mentioned that there's more surface area along the edge when it's toothy, hence more cutting area and a longer lasting edge.

Experiment for yourself. You don't need belts to try this, you can do it on the stones you already have (220 and your polishing stone).


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## Dave Martell (Jun 2, 2016)

I've got some comments on this subject... 


Belt sharpening is something that pretty much has to be done on some level at some time if you're in the game to make money. I was against this at first, I tried every gadget/tool you can name to avoid belt sharpening, and then finally gave in and bought a Harbor Freight 1x30 to try - and BAM - I started to make some $$$ finally. Within a short period of time I upgraded to a larger machine (2x48). I could now handle a wide array of repairs (which is 98% of what a pro knife sharpener does) and edge knives faster. Since I was doing mostly German type knives at the time this worked out well for me. It took me MANY years more before I would even dare try to sharpen a gyuto on belts. I finally did though and this opened it up even more for me....I'll talk more about this later.

So how much time can one expect to spend per knife when sharpening on belts? In my best of days, when I was on the road working out of my truck servicing restaurants/caterers/etc, I could do 1 (German) knife every 2 mins, start to finish. A pro knife sharpener needs to do a knife in 1-2 mins - max if he/she hopes to survive. It's not just a matter of $$$ made, it's a matter of volume in time. Imagine a restaurant handing you 40-60 knives, all beat to hell, and expecting them back immediately. Yeah it's not a game for the Ken Schwantz wannabes with their 999,000,000x CBN emulsions. :lol2:

So using a belt grinder is all about speed (quantity vs quality)? Nope, not at all actually. Depending on one's approach, a fantastic edge can be made with belts, in fact I'd go so far as to say in some cases a better edge can be made with belts than with stones. 

Belt grit ratings don't match up well to stones for comparison's sake. A 220x stone is, however, pretty darn close to a 220x belt but this changes as you travel up the grits. For instance a 600x stone os rather coarse whereas a 600x belt is getting into pre-polishing territory. I use two grit belts for sharpening knives, 120x & 320x SiC. For cheap knives I apply a cheap edge, 120x is great for German knives, leaves just the right amount of bite plus it's renewable using a "steel" or ceramic rod. If an edge is polished too much there's nothing there for the "steel" to grab and refresh/realign. This is a new belt sharpeners most common mistake, he wants to impress with a 600x+ edge, and yes it impresses initially, but what happens once the soft edge collapses and the user needs to refresh it?

For Japanese knives (that's hard knives using quality steel) we can refine the edge more because the steel used and the heat treat employed provides edge retention. Still though, it's a mistake to go too high with the grit belts being used, I suggest stopping at 320x-400x (max). 

In J's videos he's using the unsupported 100% slack section of the belt to grind in his edge (create a burr), and that's OK, but I'd suggest doing this on thicker knives only. This way has a tendency to really round over and provide deep convex edge which are strong but thick. This is OK for choppers/axes/meat cleavers/etc. 

So I'm suggesting using the supported (platen) section to grind in edges for thinner knives? Nope! Grinding edges on the platen is something I only do when I have to remove a ton of steel quickly and only on thick ass knives. This simply generates too much friction and with that comes HEAT which we all know isn't good. 

I prefer the sweet spot for grinding in edges, that's the spot in the slack section immediately in front of the platen. You get firm stiffness yet the slightest bit of give. Heat is kept to nearly nothing using the slack section as the belt carries cool air to the edge and there's no friction being created from the platen beneath. 

I do prefer using the platen for deburring though. The platen provides support and eleminates (most of) the belt wrap/flex. You never want to use a leather belt unsupported unless you want a significantly rounded over ,and not-deburred, edge. An unsupported leather belt will not only round over the edge it will not deburr thoroughly causing the need for an additional step to be employed, like using an extra bench strop. 


Stropping/deburring/compounds on leather belts: 

White is OK for deburring, and will provide a keen edge but some whites are aggressive enough to raise a burr.... and yeah it's not always fun to chase one's tail while deburring. White and greens (especially greens containing chromium oxide) tend to roll the edge to the point of being too slick for most kitchen knife use. 

*Tip - WD40 removes polishing compounds from blades swiftly.



Now to go back to the idea of using a belt grinder on Japanese knives.....

I'm going to state that while they're your knives, and you can obviously do with them what you want, you may want to consider not sharpening them on belts for the following reasons.

1. Thin edges disappear VERY quickly. 
Japanese knives are almost all very thin at the edge and nothings worse than watching your precious edge thinness disappear while you chase a burr. 

2. Heat!
Thin edges turn brown and then blue quicker than thick edges do. Again Japanese knives have thin edges and can easily be burnt.

3. Angle of Attack
Japanese knives are sharpened at about half the angle of German knives, that's twice as close to the face of the belt as what J showed in the above videos. When the spine of a knife is only a few mm from a spinning belt it's easy to have an unsightly blemish form. :scared4:

4. Holes in the Edge
Because Japanese knives are so thinly ground it's very easy to grind through from one side to the other and cause a hole to appear in the edge. This "hole" will be a section of edge profile that doesn't make contact with the cutting board and will only get worse the more you sharpen the knife. All it takes is one single pause in the wrong place and it's game over - that quick.



Now I think it would go without saying but let's say it anyway - NEVER bring a single bevel to a belt grinder! :clown: OK I'll admit to having used a belt grinder to do repairs to single bevels before but this is only done as an absolute last resort and even then you're still talking about days on stones following said repairs. Just don't do it!


Bottom line.....belt grinders can be OK for sharpening cheap knives. They can also be OK for sharpening expensive knives once you have gained a sh*t ton of experience using them on cheap knives. For thin Japanese knives you should be even more experienced.

I hope this helps some...

Dave


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## Dave Martell (Jun 2, 2016)

Additional thoughts...


Using a belt grinder oriented (vertically )as J shows is a knifemaker's way. Pro sharpeners prefer the opposite, we prefer the belt in the horizontal position with the belt running away from us. The reason we like this positioning is that we can see (at the same time) the distance between the knife and belt (the angle) as well as the burr forming along the edge as we go. When the vertical position is used only one or the other factor can be viewed at a time, you have to chose between watching the angle or watching the burr form. 


The Kalamazoo 1x40 seems to be a well made machine that is popular with semi-pro sharpeners. It might be a bit too much machine/expense for the occasional user and not even machine for the pro.


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## gic (Jun 2, 2016)

Thanks Dave, very informative and useful as always!


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## Dave Martell (Jun 2, 2016)

gic said:


> Thanks Dave, very informative and useful as always!




You should come here sometime and we'll sharpen the hell out of everything we can find.


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## CrisAnderson27 (Jun 2, 2016)

Excellent posts Dave!


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## rogue108 (Jun 2, 2016)

I appreciate you going over the details again. It's great info and now I can attempt to ruin knives with my 1x30. 

To beat a dead horse even more...I just remember asking you if I could leave the cleaver for sharpening. You said bring it over and something along the lines of no problem. You were talking to Colin (Niloc) and pretty much without stopping fired up the sander, sharpened, fired up bench grinder, deburred, handed cleaver back to me, and continued your conversation. As noob at the time, I was fascinated that you literally without skipping a beat sharpened a knife and continued like on like it didn't happen. I just went back to my corner and started cutting paper like dork...


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## Dave Martell (Jun 2, 2016)

rogue108 said:


> I appreciate you going over the details again. It's great info and now I can attempt to ruin knives with my 1x30.
> 
> To beat a dead horse even more...I just remember asking you if I could leave the cleaver for sharpening. You said bring it over and something along the lines of no problem. You were talking to Colin (Niloc) and pretty much without stopping fired up the sander, sharpened, fired up bench grinder, deburred, handed cleaver back to me, and continued your conversation. As noob at the time, I was fascinated that you literally without skipping a beat sharpened a knife and continued like on like it didn't happen. I just went back to my corner and started cutting paper like dork...



Hahahahaha


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