Mueller 4-Stage vs Longzon 4-Stage Sharpener Side-by-Side Comparison

Anh Ngo
Anh Ngo
Reviewer
Nguyen Ntk
Nguyen Ntk
Visual Specialist
Reviewed
Our recommendations are made independently through research and testing following our review procedure. We may receive commissions from purchases made via our links at no additional costs to you.
Tested Using Methodology v1.1
Updated Nov 28, 2022
Tested Using Methodology v1.1
Updated Nov 28, 2022
Mueller 4-Stage Manual Knife Sharpener Review
Longzon 4-stage Manual Knife Sharpener Review
Knife Sharpener type
manual
manual
Power
0W
0W

Our Verdict

7.6
Overall Score
  • Performance (50%)
    6.7/10
  • Design (15%)
    9.1/10
  • Ease of Use (35%)
    8.3/10
7.0
Overall Score
  • Performance (50%)
    5.6/10
  • Design (15%)
    9.1/10
  • Ease of Use (35%)
    8.2/10

Apart from their logos, the Mueller 4-stage and the Longzon 4-stage sharpeners look identical. They have a robust build and sturdy construction. Both feature three sharpening slots for kitchen knives and one for scissors. Both sharpeners suffer slightly from a high center of gravity.

When put through the test of sharpening, interestingly, the sharpeners garnered very different results. The Mueller compromised the knife’s edge for quick sharpness, while the Longzon prioritized a smooth, shiny edge over sharpening time and serviceability. 

In the world of ‘convenience’ manual sharpeners, the one that makes the knife cut first has an edge, so the Mueller seems to be the more practical choice.

Performance

6.7
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
5.6
Performance Scores
  • Sharpening Time to Cut a Lemon (35%)
    1.0/10
  • Maximum Sharpness Achieved (20%)
    6.0/10
  • Edge Smoothness (20%)
    9.0/10
  • Material Retention (25%)
    9.0/10
8.8

Sharpening Time to Cut a Lemon

1.0
  • 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.

  • Sharpening Time: 3 minutes 10 seconds
  • Cutting Feel: Swift and smooth

The Longzon sharpener was disappointing in this test: It took 190 seconds on average to sharpen a dull knife to the level where it can slice a lemon with ease. Three minutes doesn’t seem so long, but when you’re repeating a motion on a small device, it can feel like an eternity.

Unlike the case with the Mueller, the tungsten carbide blades on this device offer a tight and steady brace. For some reason unknown to us, the knife edge just didn’t get keen quickly enough with it.

8.0

Maximum Sharpness Achieved

6.0
  • 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.

  • Sharpening Time: 6 minutes
  • Sharpness Level: 7 (ripe tomatoes)

We doubled the time in the lemon-cutting test and the Longzon sharpener could only up the knife sharpness by one level. It cut through a ripe tomato effortlessly, and took two forceful swipes to sever the tough skin on a chicken breast. This isn’t a bad performance, per se, but we had expected more from the sharpener as it looks so well-made.

5.0

Material Retention

9.0
Mueller 4-Stage Material Retention
Mueller 4-Stage Material Retention 1
  • 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.

Longzon Knife Sharpener Material Retention
Longzon Knife Sharpener Material Retention 1
  • Sharpening Time: 1 minute
  • Target Sharpness:

On most devices that employ tungsten carbide blades as the sharpening ‘abrasive’, the more material they remove, the quicker they work and the sharper the edge. The Longzon is not an exception. It took more than 3 minutes to produce a keen edge, so it’s not a complete surprise that it only removed a moderate amount of material from the edge in 1 minute.

4.0

Edge Smoothness

9.0
Mueller 4-Stage Edge Smoothness

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.

Longzon Knife Sharpener Edge Smoothness

We couldn’t be more impressed when we saw the knife edge after sharpening with the Longzon. It’s smooth, shiny, and balanced between the two sides — common among electric sharpeners, but a rare thing to see with manual pull-through devices. We can’t quite explain the lack of chips, grains, or unfinished shavings — we didn’t need a magnifier to see them on the edge produced by its identical cousin, the Mueller. 

At any rate, if a clean, perfect edge is what you’re after in a handheld sharpener, the Longzon should be among your top choices.

Design

9.1
design Scores
  • Build Quality (75%)
    9.1/10
  • Grip (25%)
    9.0/10
9.1
design Scores
  • Build Quality (75%)
    9.1/10
  • Grip (25%)
    9.0/10

In the Box

Mueller 4-Stage In the Box
  • 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.

Longzon Knife Sharpener In the Box
  • The Longzon 4-stage knife sharpener 
  • Instruction manual
  • Protective gloves 

The Longzon sharpener comes in a nice cardboard box with lots of instructions and contact information printed on it. Then there’s a leaflet that features the instructions in five different languages. Two thin gloves are included in the package, presumably for protecting your hands during sharpening, though this is mentioned nowhere in the manual.

Dimensions

Mueller 4-Stage Dimensions
  • Length:
    9.3" (23.6 cm)
  • Width:
    1.8" (4.6 cm)
  • Height:
    3.1" (7.9 cm)
  • Weight:
    8.6 oz (244 g)

Longzon Dimensions
  • Length:
    9.3" (23.6 cm)
  • Width:
    1.8" (4.6 cm)
  • Height:
    3.1" (7.9 cm)
  • Weight:
    8.7 oz (246 g)

9.1

Build Quality

9.1
Mueller 4-Stage Build Quality

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.

Longzon Knife Sharpener Build Quality

The Longzon sharpener has a strong build with quality materials and a robust design. Its working section, handle, and base are securely attached to each other, which helps with stability during sharpening. The design is function-oriented, but everything has a nice, flush finish. We couldn’t expect better, especially for its price.

9.0

Grip

9.0
Mueller 4-Stage Grip
  • 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.

Longzon Knife Sharpener Grip
  • Material:
    ABS, TPR

The Longzon has a nice, substantial grip. There’s plenty of space for larger hands or for those who want their gripping hand to be as far away from the knife as possible while sharpening.

The upper side of the grip is a plastic that’s very soft to the touch and has decent friction. The lower side features finger nubs for a firmer grip.

Working Section

Mueller 4-Stage Working Section
Mueller 4-Stage Working Section 1
  • 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.

Longzon Knife Sharpener Working Section
  • Levels of Sharpening:
    Sharpen, Hone, Polish
  • Abrasive:
    Tungsten carbide blades, diamond rods, ceramic rods
  • Mechanism:
    Pull through
  • Sharpening Angle:
    20 degrees

The working section features one slot for scissors and three for kitchen knives. Instead of a prep slot, you start sharpening your knives with the tungsten blades and use the diamond and ceramic rods for further honing.

The whole working section is covered with stainless steel, making it easy to clean should the need arise.

Base

Mueller 4-Stage Base
  • 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.

Longzon Knife Sharpener Base
Longzon Knife Sharpener Base 1
  • Material:
    ABS
  • Feet Type:
    EVA feet

The Longzon has a red ABS base that makes it look like a Louboutin shoe. It tapers from the working section downwards, but the base size is sufficient to keep the device in place. 

It boasts two flat, but effective, anti-slip pads underneath the working section and the grip.

Ease of Use

8.3
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
8.2
usability Scores
  • Slot Arrangement (20%)
    7.0/10
  • Insertion (20%)
    9.0/10
  • Pulling Through (10%)
    8.0/10
  • Stability on a Clean Surface (40%)
    8.5/10
  • Stability on a Wet and Dirty Surface (10%)
    8.0/10
7.0

Slot Arrangement

7.0
Mueller 4-Stage Slot Arrangement

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.

Longzon Knife Sharpener  Slot Arrangement

The Longzon’s layout of sharpening slots is identical to the Mueller, and in our experience, not ideal. We’d rather move Slot 3 (diamond rods) to the front of the row to serve as a prep slot.

Otherwise, the arrangement is simple and easy to work with — all the slots have the same grind angle and are designed for the same types of knife edge. The natural progression of coarseness (or fineness) level means you never have to pause halfway through in fear of going the wrong way.

9.0

Insertion

9.0
Mueller 4-Stage Insertion

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.

Longzon Insertion

Insertion was easy with the Longzon: Its wide slots with a neat design offer enough space for the blade to get in without obstruction. You may cut into the wall if you go too fast, but that should be rare.

7.5

Pulling Through

8.0
Mueller 4-Stage Pulling Through

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.

Longzon Pulling Through

With the U-shaped plastic frame placed too close to the sharpening rods, we ended up cutting into them after almost every swipe. Even a few more millimeters would avoid this. But other than that minor annoyance, the Longzon offers a great sharpening experience. Its blades and rods provide a steady brace with decent and stable friction that’s evident in the near-perfect knife edge it creates. It’s also effortless to keep the blade straight during sharpening — we never ended up with an uneven edge, as was the case with its Mueller counterpart.

8.5

Stability on a Clean Surface

8.5
Mueller 4-Stage Stability on a Clean Surface

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.

Longzon Knife Sharpener Stability on a Clean Surface

Even though the base is tapered, it’s still large enough to support the sharpener. The rubber pads offer good contact areas and great friction, so the device wouldn’t slip on a countertop. We didn’t have to use excessive force to keep it steady during sharpening, just a firm grip.

8.0

Stability on a Wet and Dirty Surface

8.0
Mueller 4-Stage Stability on a Wet and Dirty Surface

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.

Longzon Knife Sharpener Stability on a Wet and Dirty Surface

The slippery countertop wasn’t much of a challenge for the Longzon either. It did glide a bit when we intentionally used more force to sharpen, but it fared well most of the time.