Knipex Twin Grip vs Stanley FatMax Slip Joint Pliers

When Knipex Tools released the Knipex twin grip slip joint pliers, I know you thought it was the first innovation on the classic slip joint pliers. What you don’t know is that Stanley Tools had the first stab at innovating around the classic 2-position slip joint pliers?

In this article, I look at the innovative Stanley Fatmax push-lock slip joint pliers and compare with the Knipex Twin Grip pliers. These modern-style slip joint pliers are quite similar and different at the same time. But first, let us understand what are slip joint pliers?

What are slip joint pliers?

Slip joint pliers are a type of gripping pliers with an adjustable joint. They offer better gripping ability than combination pliers but not better than water pump pliers. They are in between. You can use them to grip small flat-sided and round objects.

Slip joint pliers typically have two joint positions. However, there are some modern innovations of the classic slip joints that offer more than 2 slip positions.

Some of the most common modern-style slip joint pliers are the Knipex Twin Grip pliers and the Stanley Fatmax push-lock slip joint pliers. I have reviewed the Knipex Twin Grip extensively in this post: Why Knipex Twin Grip Pliers are a big deal

Stanely Fatmax 84-646 Slip Joint Pliers Features

Stanley 84-646 fatmax slip joint pliers

As I mentioned, Stanley FatMax push lock slip joint pliers are the first tweak to the old design of slip joint pliers. They were released before Knipex Twin Grip.

Unlike classic slip joint pliers that have two adjustment positions, these innovative-style push button pliers from Stanley Tools have 3 positions. Also, they feature a push-button for adjusting the jaws. You don’t need open the handles to slide the joint to another position. Instead, you just push the button and slide to lock the joint in any of the three positions without necessarily opening the handles.

This push-lock adjustment style is similar to that of the Knipex Twin Grip. However, the twin grip has a box joint like that of Knipex Cobra that offers up to 5 adjustment positions.

Another unique feature of the Stanley FatMax slip joint pliers is the multiple grip sections on the jaws. Unlike regular slip joints which mostly have a single gripping section, the FatMax has three grip sections.

multipurpose jaws of stanley fatmax slip joint pliers
Multigrip jaw sections

They have a large curved gripping section with large horizontal teeth. This is for gripping round pipes. It is immediately next to the fulcrum.

The second gripping section is small and slightly curved with lower profile horizontal serrations. This section is for gripping tiny round objects such as nails. You can use it to pull nails from wood.

Lastly, the front part of the jaws is a flat serrated section for gripping flat materials. You can use it to grab any material either to pull or manipulate. I like to use them to grip thin metal blades to form them into any shape.

The Stanley FatMax slip joint pliers are made from heavy-duty induction-hardened alloy steel. They are coated with black oxide to prevent rusting. The handles have comfort grip material that makes the tool very comfortable in the hands. The workmanship is not that great because it is not uncommon to come across a pair with misaligned jaws or discolored coating.

Stanley Fatmax Slip Joint Pliers vs Knipex Twin Grip

knipex twin grip vs stanley fatmax slip joint pliers

Because I already reviewed the Knipex Twin Grip extensively in a different article, I will go straight to compare its features with Stanley Fatmax to point out the similarities and differences that these two creative styles of slip joint pliers have.

Similarities and differences


One of the similarities between these two innovative styles of slip joint pliers is size. Both of them are 8 inches long from end to end. Also, the overall form factor looks similar.

However, the fatmax comes only with bi-material comfort handles whereas the Knipex twin grip has both regular and comfort grip handles.

Jaw grips

The second similarity is the multiple grip jaws. Both pliers have multipurpose jaw grips for gripping different shapes of material including hex, rounded, and flat-sided shapes. You can use them to grasp small metal pipes, bolts, and flat metal blades.

The difference is how the grips are designed and their purpose. While the fatmax has two round gripping sections, the twin grip only has one V-shaped section. V-shaped jaws offer more points of contact with hex-shaped objects and are also good for gripping round shapes. Round jaws, on the other hand, grip round stock better.

Both pliers have flat gripping sections at the end of the jaws but the Twin Grip also features a front grip with vertical serrations for extracting screws. It works just like the Engineer screw extractor pliers.

Adjustment mechanism and positions

The third similarity is that the joint on both pliers can shift to more than 2 positions. Also, they use a release button to adjust between the different sizes.

The difference, however, is that the Stanley FatMax shifts to 3 positions only while the Knipex Twin Grip offers 5 different positions. The twin Grip has a box-joint design with fine adjustment grooves where the push-button mechanism adjusts and locks.

Which is better? Stanley FatMax Slip Joint Pliers or Knipex Twin Grip

Both of these modern types of slip joint pliers are nice upgrades to the classic slip joint pliers. They are safer to use and more versatile. Unfortunately, they are also heftier because of the additional features.

These innovative-style slip joint pliers are safer because they use a push-button mechanism that eliminates the risk of pinching your hand. Regular slip joint pliers are notorious for biting the soft part between the thumb and front finger when opening the handles to shift the joint.

That being said, the Knipex Twin Grip has a far superior feel and workmanship than Stanley Fatmax slip joint pliers. This is because of the excellent quality control at Knipex Tools.

Stanley Tools fumbled with the quality control of the fatmax slip joint pliers. You will be in luck if you find a pair with jaws that align properly and no scratches on the coating.

The Twin Grip is also more versatile. You can use it to do everything that a pair of Stanely FatMax slip joint pliers does, in addition to using the front grip to remove stripped screws. Isn’t that cool?


Although the Knipex Twin Grip pliers are more expensive than the Stanley fatmax, they are worth the price. They are the best slip joint pliers for professional use, especially where regular slip joint pliers would be limited. For instance, the push-button technology makes it easy to adjust these pliers even in tight spaces.

On the other hand, I would recommend the Stanley fatmax slip joint pliers for use in home projects and DIY stuff. They are inexpensive and more importantly, their overall build quality is not that great for professional use, IMO.

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Julio a.k.a Pliersman is the owner and creator of the Pliersman Website. A blog that informs and educates you about different types of pliers and their uses. Julio is a handy person and has used a variety of pliers including general-purpose and specialty pliers to accomplish tasks. He holds an electrical engineering degree and has previously worked as an O&M manager for minigrids where his love story with pliers and other tools began.