Work Sharp Ken Onion Electric Sharpener In-depth Review

Anh Ngo
Anh Ngo
Lap Vo
Lap Vo
Head of RTR
Nguyen Ntk
Nguyen Ntk
Visual Specialist
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Work Sharp Ken Onion Electric Sharpener In-depth Review
Type: electric
Sharpening Stage: null

The Work Sharp Ken Onion is a versatile electric sharpener for kitchen knives and outdoor tools that allows you unpreceded control in terms of angle, speed, and abrasives. It also creates keen, mirror-like edges that are close to what’s achievable with a series of whetstones. The compromise is that it takes longer to master than other sharpeners, and the uncontrolled dust means you can’t use it near your food prep area.

Things We Like

  • It accommodates different edge angles and blade types
  • You’re in control of the speed 
  • It can produce a mirror-like finish
  • It works on various tools other than kitchen knives

Things We Don’t Like

  • It throws dust into the air 
  • There’s a learning curve
  • It’s tricky to get even bevels
  • Updated Nov 22, 2022:

    Review published.

We bought the Work Sharp Ken Onion electric sharpener in October 2021, put it through our initial battery of tests, and ever since have been using it to perfect the knives our manual sharpeners failed to complete. After more than a year and dozens of knives, we’re excited to test and review this ferocious machine again.

The Work Sharp Ken Onion is a well-built, durable machine. It offers many options in terms of both edge angle and sharpening speed, and can create edges with mirror-like sheens to them. The device is not particularly difficult to use, though it takes a while to get the hang of. The lack of safety features was the only part that caused us consternation.

Work Sharp Ken Onion Electric Sharpener In-depth Review


How We Tested

The Work Sharp Ken Onion took longer than most to sharpen a knife to Level 9 on our Practical Sharpness Scale, but it also produced the smoothest, shiniest edge without removing excessive amounts of steel. It can run continuously for 25 minutes or more without overheating, making it an ideal machine for binge sharpening.


The Ken Onion sharpener took longer than most others to bestow an edge to a uselessly dull knife. For over 9 minutes, we made a total of 40 strokes through the Coarse, Medium, and Fine belts before the test knife could cut through raw beef tendon.

The machine wasn’t particularly fast when it was brand new, either: It took 8 minutes 29 seconds to get to the same sharpness level when we first tested it one year ago. However, we’ve used this set of belts to sharpen more than a dozen knives since, and the abrasives have obviously worn down quite a bit. In the future, we’ll conduct this test again on new belts and compare the results.


Work Sharp Ken Onion Electric Sharpener Edge Quality

The Ken Onion produced an extremely fine edge with no chips or scratches—the finish reflects light so well we had a hard time photographing it. A smooth edge is not necessarily sharper, but it allows your kitchen knives to glide through food to make a neat cut. In other words, it won’t tear the surface or squish the innards. The only other way to achieve this mirror-like finish is to spend at least half an hour with a series of whetstones.

Because the belts are soft and flexible, they create a convex edge, which is supposed to be stronger than a traditional edge. However, sharpened to a 17.5 degree angle, we expected a little more edge height, which would help the knife cut through dense foods such as large carrots or pumpkins.  

We also ended up with uneven bevels almost every time we sharpened with the Ken Onion. This happened despite our efforts to keep the knife straight. We’re not sure if the edge angles are inconsistent between the two sides or if it’s due to the fact that we made an upstroke on one side and a downstroke on the other side. The consolation is that the discrepancy was very minor.


Work Sharp Ken Onion Electric Sharpener Material Retention

The Ken Onion throws diaphanous dust in all directions, so it was tricky to collect the debris. Regardless, the amount was meager compared to other electric sharpeners. The belts didn’t have to remove much material to produce a low convex edge. 

If you have bolstered knives, this is the best sharpener for them. The belt and angle guide make it easy to get to the knife heel, and the modest material loss means it’d take a long time before you see a recurve, too.

We suspect the Extra Coarse belt would be harsher on the edge, but that one is intended for damaged blades or tools, so we didn’t use it in the test.


Passing our 25-minute test was a piece of cake for the Work Sharp Ken Onion. Granted, we had to pause it a few times to change the belt, but the motor was never a limiting factor. After all, the unit is rated for 60 minutes of continuous operation. That’s plenty to cover all the knives in a typical house. If you like to sharpen all your blades in one go, this machine is your best friend.

Unlike other electric sharpeners, the Ken Onion’s design allows you to customize nearly everything—the grind angle, the speed, and even the type of abrasive. It sports a brawny body with lots of visible screws, levers, and complicated parts. The appearance can be a bit intimidating unless you’re handy with electric tools.

Work Sharp Ken Onion Electric Sharpener In the Box
  • Work Sharp Ken Onion electric sharpener
  • 5 x abrasive belts (Extra Coarse, Coarse, Medium, Fine, Extra Fine)
  • Quick start guide
  • User’s manual 
  • Stickers and advertisement leaflets 

The Work Sharp Ken Onion comes in a simple cardboard box with the manuals and a bag of belts.

Each of the five abrasive belts are color-coded. The names and grits of the three you’ll use most (Coarse, Medium, and Fine) are also printed on the inside of the belt. The Extra Coarse and Extra Fine belts are not labeled, but they’re easily distinguishable by their texture.

The user guide book is in English. It’s completely thorough, covering everything from safety information to troubleshooting. We particularly appreciate the reference chart for sharpening different types of knives. Each is listed with the angle, speed, necessary belts, and number of strokes per side—a great resource for first-timers.

Work Sharp Ken Onion Electric Dimensions

Work Sharp Ken Onion Electric Sharpener Power Cord


Chef’s Choice Trizor XV Electric Sharpener Build Quality

The Work Sharp Ken Onion doesn’t seem to be made of special materials, but it’s solid, sturdy, and offers excellent stability. The handle is ergonomically shaped and tacky enough for a good grip. And although many parts are detachable, they all feel rock-solid when it’s assembled. Nothing rattles around. 

The belts are so small and thin they almost look fragile. Despite that, ours are still intact, only showing the normal signs of wear and tear from more than a year of use on dozens of knives.

We thought the nooks and crannies are a bit too numerous; they all collect dust with every sharpening session. Still, we’ll admit the machine wouldn’t look as cool and ferocious without them.


Work Sharp Ken Onion Electric Sharpener Angle Adjustability

Our favorite thing about the Ken Onion is that it offers more angle choices than any other electric sharpener out there. Its own predecessor, the Work Sharp Standard, is capable of only 20 or 25 degrees. The Ken Onion sports a sharpening-angle guide that can adjust between 15 and 30 degrees at 1-degree increments. Technically, you could also achieve these angles using a whetstone, but that takes practice and skills that most people don’t have.


With small abrasive belts and open angle guides, the Ken Onion can handle most normal kitchen knife sizes and is better at small knives than any other machine.  

Knives that are particularly large and thick, such as 12-inch chef’s knives, may be a bit tricky to sharpen on this machine, as they’ll cut into the small edge guide. You can remove the angle guide to sharpen them freehand, but it’s hard to maintain a consistent angle that way.


Work Sharp Ken Onion Electric Sharpener Edge Type

The small abrasive belts of five different coarseness levels give you more sharpening options than most. The Ken Onion still can’t sharpen micro-serrated edges or individual teeth on a bread knife, but it can give a non-serrated bevel a good hone. You can sharpen wavy edges, very short tool blades, and even gut hooks with these belts!

Ease of Use

How We Rated

The Ken Onion gives you a lot of control and makes it simple to sharpen with precision. However, that also means its use involves a learning curve. It’s not a tool to run casually on your kitchen countertop. Wear protective gear and use it outside or in the garage to keep the metal dust out of your food and off your cookware.


Work Sharp Ken Onion Electric Sharpener Setup

It took us a while to figure out how to set this machine up. Adjusting the angle, installing the belt, setting the edge guide, setting the speed, turning it on, and locking the power switch all took a little learning. 

If you have small hands you might find it tricky to press the lock button and hold the power switch at the same time. We initially resorted to holding the handle in one hand and pressing the button with the other. 

A full sharpening run means progressing through the belts. Because they fit tightly, they can be frustrating to remove and install. Make sure you are gentle or you may break the belts, especially the finer ones.

Once you’ve learned the ropes, the setup won’t feel like such a hassle. It will begin to feel natural after the third or fourth knife. Just don’t start with your favorite or most expensive knives.


Most other electric sharpeners use abrasive discs, which sometimes push the knife blade away, making it tricky to insert the blade. The Ken Onion’s abrasive belts, on the other hand, can flex to accommodate the blade. Insertion is thus quite straightforward. Depending on the edge angle you pick, you can even glide a knife with a full bolster through its angle guides.

The edge guide helps keep the knife stable. What we haven’t figured out, even after a year of use, is how to avoid cutting into the guide when sharpening larger, heavier knives.


Despite the lack of a flat rectangular base, the Ken Onion is perfectly stable on a table. The vibration is minimal when you hold it, too. We think it’d be better if the abrasive belts were thicker and less flexible, but if you pay attention while sharpening it’s not difficult to keep the blade straight.


Work Sharp Ken Onion Electric Safety

We’ve sharpened a lot of knives with the Ken Onion—often several in succession—and its temperature always stays below 100°F. The risk of burning and skin damage from heat is minimal with this one.

It’s a loud piece of equipment, however. Sometimes, the noise can reach nearly 97 dB. That’s enough to cause hearing damage if used continuously for 30 minutes. 

As mentioned, the machine also propels fine metal dust all over the place, which may lead to respiratory problems if inhaled. The dust may also get into your food or cookware.

The user guide specifically requires users to wear safety glasses, dust masks, and ear protection. We strongly advise you to follow these instructions. 

Because the abrasive belt is exposed at all times, there’s the risk of injury if you accidentally touch it. It’s a good idea to release the power switch and turn the device off as soon as you finish.

All in all, we’re convinced this tool belongs in a garage and away from your cooking area, children, or pets.


The Work Sharp Ken Onion has quite a lot of nooks and crannies where metal dust accumulates. It will need regular cleaning with a fine brush. This doesn’t cause damage to the device itself, though we’ve read Amazon reviews by users who noticed micro scratches on their blades after sharpening. While the 1-year warranty seems standard, replacement parts such as the edge guide and abrasive belts are very easy to find online.

The Work Sharp Ken Onion Compared to Other Sharpeners

Of all the electric sharpeners we’ve tested, the Work Sharp Ken Onion is the most versatile and customizable, but it’s not a casual tool for everyone. 

If you’re looking for something more user-friendly, check out the Chef’s Choice Trizor XV. It only sharpens to a single grind angle but it’s faster and simpler to use. It’s also slightly more expensive than the Ken Onion, but there’s a reason we named it our best electric sharpener. 

The Presto Eversharp also offers decent sharpness without requiring much effort or bleeding your wallet dry. Of course, you can’t expect the same edge quality from it and you get no control over the grind speed or angle.