This is the second instalment of a new blog series, where I try out sharpening mechanisms. I’m not yet fully sure about the format – I will write about things that matter to me, such as build quality, capability to sharpen, but also very subjective things like how it feels to sharpen with this. If I was you, I would expect this to be a rare blog segment. The reviews will be independent from the manufacturer, without control over what I test or write. I am not paid nor do I receive anything from the manufacturer if you decide to buy one.

If you make a sharpening device and you want me to test it, feel free to reach out.

KMFS Vantaedge

Today’s sharpening mechanism is made by the Czech Company KMFS. It is a portable, high quality guided sharpening mechanism that accepts the standard format 1×6″ sharpening stones. As far as I know, they produce locally in Europe in the Czech Republic – wonderful! I love it when things are manufactured close to me. At the time of this review, the mechanism retails for about 350 Euro. The device was a loaner unit given to me by the manufacturer, but they had no control over this review and didn’t see it before it was uploaded publicly.

The assembled Vantaedge with optional stand/base.

The Vantaedge has been on the market for a couple of years already. It’s a bit different than most mechanisms on the market – the angle adjustment is done via a fixed joint near the swivel mount. This is (again, like in Part 1), similar to a “Bogdan” principle. This means the angle is not dependent on the thickness of the stone or the geometry of the knife – within a certain, small limitation. More about this at a later time.

The advantage here – and especially considering the high build quality yet affordable price – is that sharpening with this device is easy to learn. You do not have to adjust the angle of the mechanism all of the time – and I would even go so far as to say that the 4 positions supplied are enough. While experimenting with angles is interesting, for knives you use and sharpen a lot, it makes sense to keep a constant angle. When touching them up, there is no need to then start on coarser grits – which makes routine maintenance on sharpening quicker. I can tell you from personal experience, that since I’ve started keeping all of my cooking knives at the same 17 DPS, I spend a lot less time on keeping them in peak sharpness condition!

The device comes in a very nice hard case with precise foam cutouts. Moreover, 3 electroplated diamond stones are supplied with it. The small size and modular nature make this a very compact, portable sharpener. There is an optional stand that makes it very solid – personally, I’d say that the stand is a very nice option to have and I’d definitely buy it together with the mechanism. But without the stand, in the relatively small case, it’s a super portable solution!

Packaging and delivery content of the KMFS Vantaedge.

Build Quality

The device is completely milled. Individual components are made from “aerospace grade” aluminium (Type EN AW 7075), whereas the rods and bearings are made from ground and hardened steel. The device has a solid feel, the parts are milled from all sides and in my opinion is has a very aesthetically pleasing design.

Detailed views of the different components of the Vantaedge. Note the full surfacing of pretty much every part – this shows special care by the manufacturer. Every surface is finished to their design, which is a nice statement of quality.

Overall, the device has a solid feel to it. The aluminium parts look like they are anodised, but in their natural colour. I found it pretty prone to picking up dirt / fingerprints. A slight bead blasting and maybe an anthracite colour for the anodising would appeal to me – but overall, it’s a solid device with good manufacturing quality in premium materials.

Working Principle

The device works a bit different than other guided sharpeners on the market. Instead of adjusting the angle via a height mechanism, the angle of the guiding rods is constrained via a swivel joint:

Angle mechanism of the KMFS Vantaedge. In the standard configuration, 4 different angles (15, 17.5°, 20° and 22.5°) are possible. The manufacturer offers an optional 1° adjustment, and recently came out with an infite adjustable mechanism to set the angle you desire.

Here, the vertical rod can move up and down freely, and the stone moves back and forth on the guided rods. By coming into contact with the blade, the whole system complies with the fixed angle set in the back – this enables sharpening without having to adapt to blade width or stone thickness. It’s a very slick principle – and advertised as

“This sharpening system is the first in the world, which is able to completely eliminate the effect of the raised facet at the tip of the knife and enables absolutely precise repeated sharpening of the knife without any demands to repeat the knife clamping position.“ KMFS Homepage, accessed on Friday, 27th of March 2026

This is…not fully correct, but also better than on other guided sharpening systems. Let me explain it in a couple of sketches – for this I modelled up the mechanism in CAD:

Mockup of the mechanism. The model uses joints and “solid contacts” to be interactable. Modelled in Fusion 360.

Now, the constraint at the back of the guided rods (alpha angle) will force the vertical rod to move up and down, depending on stone thickness and blade position. This forces the angle onto the blade. The angle at the blade (beta angle) is calculated by simple geometry: 180° – gamma – alpha = beta. The confusing part here might be: The manufacturer wrote the angle that exists on the blade onto the angle selector, not the actual angle at that point.

Now, if we had a flat blade (aka: no curvature), every point along this blade would be on the same plane, and the mechanism would work flawlessly.

We can see this in my model if we swivel to the left side, where the blade is more regular / straight:

Here, the contact is ideal: perfectly matching the bevel of the blade.

If we swivel the mechanism to the other side, where the tip of the knife is more curved:

The angle is NOT held correctly, and we are able to detect a small deviation:

Illustration of the angle error by leaving the plane. Picture with the angle measurement shows a small distance between the contact to allow for easier visualisation. Please note that this is an extrem curvature! The error in real applications will likely be smaller.

This is a bit less than on a regular guided system, as reduced distance between vertical rod and blade is accounted for here – but because we left the previous plane, a change is still happening.

So, in summary: on a straight blade, the mechanism would work perfectly, and compensate any changes in stone thickness. But when you have a strongly curved blade, just like every other system, a small error at the tip will appear. It is less pronounced than on “angle-adjust guided rod systems”. The compensation for stone thickness still works though!

Sharpening Process

The use of the device is pretty straightforward: put the stone into the spring loaded holder. Clamp your knife down with the very solid clamps.

Detailed photos of the individual components: the clamp for the knife, the stone fixture and the assembled and ready to sharpen mechanism.

On the vertical rod, there is an adjustable spring – pressure control can be realised by adjusting the position. It also helps with the movement of the rod – makes it a bit more smooth!

Detail of the pressure-control spring. It compensates for the weight of the aparatus and is very helpful in a smooth motion.

The knife is sharpened like on every system by employing a back and forth movement of the stone. One can grab ondo a small handle for that:

It’s generally very smooth when going back and forth:

I found the mechanism to stick slightly when employing edge trailing moves only:

This got a bit better by lubricating the rods and practicing. I would not call it a dealbreaker, but it stuck out to me during sharpening.

In order to sharpen the second side of the blade, one takes out the guiding vertical rod, lifts the central clamp / main body, flips it 180° and puts everything back together. I think this is the biggest weakness of the system – it takes some time getting used to, and definitely even with practice takes longer than a swivel mechanism. On the other hand, it’s remarkably stiff and there’s no angular error by deflection.

Conclusion

Overall, I’m a little bit torn. Things I like about this system: well made, high quality materials, made in Europe. It’s easy to use, there is no learning curve for setting the angle, and stone thickness is compensated flawlessly without user input. It is portable and relatively affordable.

During sharpening, because of the long levers, sometimes the mechanism feels a bit “sticky”, but this improves with practice. The angle along the curvature of the blade is fixed better than on other guided sharpening systems, but not perfect. I found applying oil to the stone a bit tricky, as the stone is fixed with the abrasive facing downwards. The “flip” mechanism is a very simple solution – but I found this to be the biggest weakness of the system. I’d love it if the manufacturer would implement a swivel mount, so one didn’t have to take it apart everytime.

Honestly? I think this is the ideal system to start into the hobby. Instead of dropping a couple hundred bucks on an import from overseas, you can support a wonderful engineering and manufacturing company from Europe, get a cool, mobile device that gives you wonderful edges. Craftsmanship & quality is spot on. If you already have a larger guided mechanism, it might just be the solution to carry along to sharpen at a friends place, and it’s definitely worth trying out because of the special mechanism involved here.