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Chef's Choice 4643 vs. Mueller 4-Stage Manual Sharpener Side-by-Side Comparison

Anh Ngo
Nguyen Ntk
Visual Specialist
Tested Using Methodology v1.1
Updated Mar 17, 2023
Tested Using Methodology v1.1
Updated Mar 25, 2023
The Chef’s Choice 4643 knife sharpener
Person holding the Mueller 4-stage manual knife sharpener in one hand
Knife Sharpeners type

Our Verdict

Overall Score
  • Performance (50%)
  • Design (15%)
  • Ease of Use (35%)
Overall Score
  • Performance (50%)
  • Design (15%)
  • Ease of Use (35%)

The Chef’s Choice 4643 may be double the price of the Mueller 4-stage sharpener but our test results revealed the latter to be the more effective one.

The Chef’s Choice 4643 has a great design. Though lightweight, it sports four rubber feet that keep it well balanced and in place during the hardest pulls. In terms of stability, the Mueller is okay but it does depend on its heavy weight and the tall body doesn’t particularly help either.

That being said, the Mueller fared much better in speed and sharpness. The Chef’s Choice 4643’s unconventional disc design, while performing well at preserving knife material, couldn’t bring a keen edge to it.

Chef's Choice Manual Knife Sharpener’s Performance

Mueller 4-Stage Knife Sharpener’s Performance
Performance Scores
  • Sharpening Time to Cut a Lemon (35%)1.0/10
  • Maximum Sharpness Achieved (20%)6.0/10
  • Edge Smoothness (20%)5.2/10
  • Material Retention (25%)7.0/10
Performance Scores
  • Sharpening Time to Cut a Lemon (35%)8.8/10
  • Maximum Sharpness Achieved (20%)8.0/10
  • Edge Smoothness (20%)4.0/10
  • Material Retention (25%)5.0/10

Sharpening Time to Cut a Lemon

  • Sharpening Time: 4 minutes
  • Cutting Feel: Slightly heavy

The Chef’s Choice took its sweet time to sharpen and was consistently among the slower ones in all our test attempts. It took a whopping 4 minutes to bring the test knife from uselessly blunt to adequately usable on a lemon. Even then, the knife needed a little more force than usual to execute the cut. You’d get better results within the same time using a whetstone.

We wouldn’t count on this one as a convenient sharpener to prep our knife before a cooking session.

  • Sharpening Time: 1 minute 15 seconds
  • Cutting Feel: Swift and smooth

The Mueller isn’t the speediest of sharpeners, but it works fast enough. We put it through the lemon test twice, and it took 60 and 90 seconds respectively to complete the task. This is quite a reasonable time range, considering how dull we made the knife before testing.

Skipping the diamond rods won’t affect the result. We only used them to rid the knife edge of metal particles and make sure it was as smooth as it could be, but if you’re in a hurry, the ceramic rods alone would suffice.


Maximum Sharpness Achieved

  • Sharpening Time: 6 minutes
  • Sharpness Level: 7 (Ripe tomatoes, 1 swipe)

The blade had no trouble slicing its way through a ripe tomato in one swift motion. The chicken breast posed much more difficulty: Its slippery skin made it impossible for the test knife to slice clean-off in one go. Two rather heavy attempts were needed to sever the pieces, so we decided to keep the Sharpness Level at 7 instead of 8-.

This sharpness level should allow your knives to complete most food prep tasks with mild effort, but we usually expect more from a device with such a high price tag. We can’t count the number of sharpeners that cost one half or even one third of its price that can offer a better performance.

  • Sharpening Time: 6 minutes
  • Sharpness Level: 8 (Chicken breast with skin, 1 swipe)

After 5 minutes on Slot 2 and 30 seconds on each of the remaining slots, our test knife was able to cut through a raw chicken breast with the skin still attached. It did need a second swipe to sever the tough, slippery fat and skin, but this is the case for most devices.


Edge Smoothness


Chef’s Choice advertises ‘two distinct facets set at different angles that form a longer lasting, arch-shaped edge’. The sharpener indeed created what looks like a double edge on our test knife. 

Unfortunately, while the secondary edge emerged sharp and convincing, the abrasives’ effects on the primary edge were so subtle they were unrecognizable even under a magnifying lens. The discs on the Honing slot were either too fine to make a difference or were placed at an angle that did not allow contact with the knife edge. 

That explains the lack of sharpness on the test knife—the secondary edge helps, but it can only do so much.

The diamond dust and ceramic rods didn’t seem to do much if anything to smoothen the edge: It came out rough with waves and small chips all across its length. I could see it with my naked eyes and feel the chips and small particles as I ran my fingers along the edge. The discrepancy between the two sides just tops it off.


Material Retention

  • Sharpening Time: 1 minute
  • Target Sharpness:

The Chef’s Choice 4643 took off more steel from the test knife than its sharpness suggested, but the amount wasn’t significant. As typical of wheel-type sharpeners, the residue was fine dust rather than coarse shavings, suggesting highly controlled grinding.

  • Sharpening Time: 1 minute
  • Target Sharpness:

The Mueller is a disappointment when it comes to preserving edge integrity. We were horrified at the size and amount of swarf the sharpener churned out after every swipe on the tungsten carbide blades. It’s all or nothing with this slot: When it works, it shaves off as much metal as it can. When it doesn’t, your knife simply glides through it, untouched.

The icing on the cake is the obvious unevenness on the two sides of the edge. We can’t quite work out the reason for this, because its sharpening slots look exactly the same as the Longzon, which created a very nice edge in our test. We re-edged the test knife and tried again, and even replaced the test knife in case it was a faulty one, but the end result was the same.

Chef's Choice 4643 Manual Knife Sharpener’s Design

Mueller Knife Sharpener’s Design
design Scores
  • Build Quality (75%)9.0/10
  • Grip (25%)10/10
design Scores
  • Build Quality (75%)9.1/10
  • Grip (25%)9.0/10

What’s in the Box With the Chef's Choice 4643 Knife Sharpener

What’s in the Box With the Mueller Scissors and Knife Sharpener
  • Chef’s Choice 4643 AngleSelect Knife Sharpener
  • 1 x instruction manual

The Chef’s Choice snugly fits into a plastic blister pack with a user’s guide included (which is also available online). The package can pop open quite easily, so there’s no need to cut it with scissors.

Besides the sharpening techniques, the manual also guides you on how to test the knife’s sharpness, and provides helpful tips to keep your knives in their best condition.

  • The Mueller 4-stage knife sharpener 
  • Instruction manual 
  • Appreciation card & promotional leaflet 

The Muller KS-4ST knife sharpener comes in a nice cardboard box. Included is a detailed user guide with safety notes and instructions on how to sharpen knives of different dullness levels.


  • Length:
    9.3" (23.6 cm)
  • Width:
    2.0" (5.1 cm)
  • Height:
    2.8" (7.1 cm)
  • Weight:
    6.6 oz (187 g)

  • Length:
    9.3" (23.6 cm)
  • Width:
    1.8" (4.6 cm)
  • Height:
    3.1" (7.9 cm)
  • Weight:
    8.6 oz (244 g)


Build Quality


Its materials do not scream ‘top-notch quality’, but the Chef’s Choice 4643 benefits greatly from an ergonomic design and robust build. The parts are well reinforced and screw-tightened, though it can be disassembled piece by piece. Finish is near perfect and matches its high price tag.

The Muller sharpener appears to be made from decent-quality materials. There’s also little to complain about regarding the construction: Its parts align well and even when we dropped the device on the floor they stayed together like a one-piece tool. We don’t like its high center of gravity and prefer a more weighted base, but at the same time, we can’t deny how well it was put together.



  • Material:

The handle extends and slightly arches itself toward the end, forming an ergonomic crescent-like shape. It’s just about the perfect size, and the coating material feels soft and grippy between the palm and fingers. Unfortunately, the handle isn’t loop-shaped. Otherwise, you’d be able to hang it on a hook to keep it within an arm’s reach.

  • Material:
    ABS plastic and rubber

The Muller has a grip that’s proportional to its wide working section. It offers lots of space for those with large hands, and there are finger nubs that make it easy to hold on to. We also appreciate the rubber padding on the upper side of the grip: It’s soft and gentle to your palm while also creating useful friction against grease or moisture.

Working Section

  • Levels of Sharpening:
    Coarse, Fine
  • Abrasive:
    Diamond-coated disks
  • Mechanism:
    Pull through
  • Sharpening Angle:
    15° & 20°

The Chef’s Choice 4643’s working section features three sharpening slots that are securely fastened into the base and covered in a shiny stainless steel sheet.

Unlike most manual sharpeners with abrasive bars or rods, it’s equipped withdiamond-coated discs. As the blade passes through them, these wheels rotate with each draw, grinding and reshaping the edge. 

Slot 1 sharpens Asian knives at a 15-degree angle while Slot 2 sharpens Western knives at 20 degrees. 

Interestingly, there’s only one slot for honing (Slot 3) for both types of knives, but the exact grinding angle isn’t mentioned in the manual. We asked the official manufacturer in an email but have so far received no response.

  • Levels of Sharpening:
    Sharpen (slot 1, 2, 3), Hone (slot 4)
  • Abrasive:
    Tungsten carbide blades, diamond rods, ceramic rods
  • Mechanism:
    Pull through
  • Sharpening Angle:
    20 degree

The Muller has a large working section with one slot for scissors and three for kitchen knives. It’s placed on a rather thick base — in fact, the Muller is among the tallest of all the devices we’ve tested. Unfortunately, this is not an advantage in the world of handheld sharpeners: A high working section only makes it more prone to toppling during operation.

the Base

Chef's Choice 4643 Manual Knife Sharpener

Mueller 4-Stage Knife Sharpener’s Base
  • Material:
    Synthetic rubber
  • Feet Type:
    Slip-proof sole (x 4)

With the bottom being a hollow gap instead of a solid whole block, the sharpener is lightweight. However, because the base is wide and the center of gravity low, it maintains its balance very well. 

The quartet of rubber feet attached at the base corners do a great job of creating friction and keeping the device in place during sharpening—we feel this is a more economical and effective design than the large pads usually seen in other devices.

  • Material:
    ABS plastic
  • Feet Type:
    Anti-slip rubber pads

The Muller has a base running from the heel of its handle to underneath its working section. The base is supported with two flat rubber pads that offer friction and keep it from sliding across the countertop during sharpening.

Ease of Use

Chef's Choice 4643 Knife Sharpener Review

Mueller 4-Stage Knife Sharpener Review: Ease of Use
usability Scores
  • Slot Arrangement (20%)7.0/10
  • Insertion (20%)8.5/10
  • Pulling Through (10%)8.5/10
  • Stability on Clean Surface (40%)9.5/10
  • Stability on a Wet and Dirty Surface (10%)7.0/10
usability Scores
  • Slot Arrangement (10%)7.0/10
  • Insertion (20%)9.0/10
  • Pulling Through (10%)7.5/10
  • Stability on a Clean Surface (40%)8.5/10
  • Stability on a Wet and Dirty Surface (20%)8.0/10

Slot Arrangement


The sharpener has labeling for the slots’ functions and designated knife types. Depending on the knife you’re sharpening, the intended order goes as 1-3 (for Asian-style knives) or 2-3 ( for European-style knives).

The slot trios share the identical size, width, and depth, so it’s easy to confuse them. We strongly advise you to look at the labeling carefully before sharpening your knives, especially during the first sessions with the device.

While the Western slot can only blunt an Asian knife, putting your standard knife in the Asian slot can destroy the edge beyond the point of repair. We actually had to throw away a test knife trying that out.

Unlike many other sharpeners where the diamond rods serve as a “prep” stage, on the Mueller, you start sharpening your knife with the tungsten carbide blades (Slot 2), then move on to the diamond rods (Slot 3) and finish on the ceramic rods (Slot 4). Interestingly, in the Amazon product description, slots 2 and 3 are swapped. 

The tungsten carbide blades remove the most material from the knife, so it makes sense that they’re the ‘coarsest’ stage. However, we found that the diamond and ceramic rods may sometimes dullen a keen edge, especially when you use both of them to ‘polish’ it. As a result, we prefer the more common setting of starting with the diamond rods for the straightening effect.




The Chef’s Choice has rather narrow slot openings, so if you’re in a rush, there’s a chance you’ll misplace the knife and cut the cover instead of inserting it into the slot. 

On the bright side, once the knife is at the opening, it’ll be smooth sailing. Because the slots taper downwards and the discs are placed deep below, the knife will slide straight down. Insertion is thus much safer for the knife edge compared to sharpeners with tungsten bars that keep threatening to clash with the edge and cause chipping.

With a long grip and a wide working section, blade insertion into the sharpening slots was effortless and didn’t require much caution. If you’ve been sharpening with mini-size devices such as the KitchenIQ, where you’re gripping right next to the sharpening slot, you will likely notice the lack of stress when working with the Mueller.


Pulling Through


Because the slots are deep and run all the way across its width (2 inches), it was relatively easy to keep the knife straight during sharpening to reduce the risk of creating uneven edges. 

That being said, there’s some room for the knife to jig sideways; when it does, you will feel a change in the friction as you pull the blade through. 

As its discs are placed deep down in the slots, the knife kept nicking into the frame, leaving lots of marks and scratches.

The test knife went through the last two sharpening slots with little problem. However, our experience with the coarse slot seemed to be hit-and-miss:  Sometimes, the tungsten carbide blades were almost slippery with no friction or pressure felt, which means they weren’t doing their job. Other times, they were tight and ended up removing too much material from the knife.


Stability on Clean Surface

Stability on a Clean Surface

This is one of the rare devices that come without a full base and can still offer excellent stability. Despite being lightweight, the sharpener stayed secure and steady on a spotless kitchen countertop, thanks to its well-proportioned structure. Those with weak wrists or shaky hands will really feel a difference with this design.

The Muller keeps its balance well on a dry and clean wooden table or marble countertop. It’s taller than most devices, but thanks to the flat and frictious base, we never had to use excessive force to keep it in place during our multiple tests.


Stability on a Wet and Dirty Surface


Moving on to the simulated messy countertop splashed with cooking oil and peppered with salt: The sharpener’s balanced design continued to keep its footing. The base did lose its traction with the contact surface and moved along with the pull, but only occasionally and not to the extent seen on most other sharpeners.

We had to be a little more cautious on a messy slippery countertop, but as long as you don’t work too fast, balance and stability won’t be an issue.