When tooling leather designs, there are times when neither a stamp nor stylus will be enough. I have practiced using a swivel knife to create deep, smooth tooling lines throughout my projects. Although I have yet to master the technique, continuous practice has shown how greatly I can improve my leather projects through intricate designs.
A swivel knife is a tooling gadget that relies on a chisel edge blade on a rotating surface, with a slot to cradle a finger. This design allows precision, pressure control, and tight contours. Swivel knife prices vary widely from around $15–$80 due to knives requiring different parts and blades.
Let’s take an in-depth look at swivel knives. Uncovering their purpose, differences, and how they may improve your tooling designs.
What Is a Swivel Knife?
A swivel knife is a leather tool used for carving designs into leather. These unique tools place blades into a rotating base that allows for tight contours when tooling leather. Additionally, their ergonomic design, with a “U” shaped finger rest, allows for the greatest control.
The blade is typically held like a pencil, with the index finger sitting in the rest. From this spot, pressure can be applied delicately. The purpose of a swivel knife is to create depth in tooling designs by cutting the leather surface, forming a valley that captures both shadows and antiquing products.
What We’ll Explore
- Clearing up Myths & Misconceptions
- When You Might Use a Swivel Knife
- Swivel Knife Quick Reference Table
- Swivel Knife Types and Variations
- Swivel Knife Characteristics
- Swivel Knife Pros
- Swivel Knife Cons
- Swivel Knife Manufacturing Process – How They’re Made
- Swivel Knife Costs
- Alternative Options to a Swivel Knife
- Experienced Tips for Working with a Swivel Knife
- My Personal Research with a Swivel Knife
- Swivel Knife Care and Maintenance
- Helpful Swivel Knife Insights
- Key Takeaways
Clearing Up Myths & Misconceptions
Those new to tooling leather may not consider the sharpness of their blade when starting. While a swivel knife is not used to cut through the leather completely, the knife makes cuts on top of the surface. Although it may seem that having a sharp blade isn’t important, as a dull blade will accomplish the same goals, keeping your swivel knife sharp is the key to clean work.
A dull blade will catch the leather more often, halting the blade and reducing precision. With a sharp blade, the tip will glide through, making the process feel much more like drawing on the leather. Even the most expensive swivel knives can be ruined with a dull blade.
When You Might Use a Swivel Knife
The purpose of a swivel knife is to draw designs into the leather, adding depth when outlining a leather design. This can be done freehand or after tracing a design onto the leather’s surface. The swivel knife will both help with curves and control depth through pressure.
Another popular use for a swivel knife is drawing guidelines for tooling. While this can be done with other tools, the swivel knife creates a more defined border and adds depth to the project.
Since the swivel knife creates shallow cuts on the surface of the leather, an antiquing gel will highlight the lines, completing the final look of the tooling design. Frederic Fontaine Perkins, from the California State University, Northridge, in Northridge, California, described the artistic capabilities of a swivel knife and explained how the tool takes a practical craft and turns it into a creative art form.
Swivel Knife Quick Reference Table
|Component Materials||Free spinning bearings, metal barrel, and tool steel|
|Common Sizes||3/8”, 7/16”, 1/2”, 9/16”, 5/8” Barrel Size 1/4”, ⅜”, 1/2“ Blade Width|
|Cost Range ($)||$15–$80|
|Recommended Maintenance||Blade sharpening and polishing|
|Recommended Storage||Completely dry with a blade cover on|
|Common Uses||Cutting designs into leather, outlining stamping areas|
|How Long It Lasts (on average)||Lifetime, with blade replacements required every 10+ years|
Swivel Knife Types and Variations
While the majority of swivel knives look similar, various blades can be used with the tool. Two main types of swivel knife blades include straight and angled. A straight blade is best for straight lines with small curves. An angled blade helps more with curved designs.
In addition, there are various sizes for both types of blades. From ¼ –½ inch, a thicker blade simply results in thicker lines. Since carving leather is an artistic process, there is no correct answer. Some crafters pick a single blade for all their needs, while others swap blades depending on the design.
Swivel Knife Characteristics
The three main parts of a swivel knife include the barrel, blade, and bearings. The barrel of the knife is what holds everything. The body of the blade may come in different sizes to better fit a crafter’s hands. The barrel can be made from stainless steel metal, brass, or titanium, depending on the quality. Swivel knife blades are an essential part of the knife.
Much like other knives, their material is important in determining how the blade will perform. A wide variety of steels are used, including D2 and M4 tool steels. In addition, ceramic blades are available for swivel knives. Ball bearings used in swivel knives are known as free spinning. It is the part that allows the barrel to swivel, giving the blade its name.
Sizing options for swivel knives begin with the barrel. From ⅜– ⅝ inch, with a large variety in between, the barrel size changes for each crafter’s need. The proper size for a swivel knife should be small enough to hold comfortably without the finger rest feeling tight.
In addition to the barrel size, the blade size on a swivel knife may vary. The blade size used for a swivel knife determines how wide the cut will be. Sizes include ¼, ⅜, and ½-inch blades. While a thicker blade may be easier to create straight lines with, a well-practiced crafter can use any size they prefer with great results.
Straight blades are flat throughout and can be used vertically or at an angle to utilize the blade’s tip. Many crafters consider the straight blade best suited for straight lines or designs with very few curves. Alternatively, swivel knives can be used with an angled blade.
Angled blades naturally create a point and focus on more detailed carving. The single point allows for tighter contours and targeted details without needing to change your angle when working with a swivel knife.
Swivel Knife Pros
Swivel knives were created for carving leather with precision. As a result, there is no better tool for the job. The spinning blade helps carve curved lines into the leather. While the blade design prevents the blade from cutting too deep due to its angle.
Swivel knives are also ergonomic in their design, similar to using a pencil with a finger rest to control pressure. These characteristics combine to provide high-quality carving, outlining, and detailing lines. Swivel knives allow for additional creative freedom when working with leather, as fine art can be added to the surface of projects.
The purpose of a swivel knife is to create depth in tooling designs by cutting the leather surface, creating a valley that captures both shadows and antiquing products.
Swivel Knife Cons
Since swivel knives are a specialty tool, their purpose around the workshop is limited. They can only be used when carving treated vegetable tanned leather. Using a swivel knife will also take a lot of practice.
From handling to pressure control, swivel knives require precision to get the most out of them. Swivel knives will also require constant maintenance to keep the tool performing well. A dull blade can quickly cause the leather to catch, tearing the leather or creating jerky lines.
Swivel Knife Manufacturing Process – How They’re Made
Swivel knives are fairly simple tools that many crafters have made themselves, as they only require three main parts. The blade, barrel, and ball bearings. The blade of a swivel knife is unique in its shape. Tool steel is ground to form a point with a heavy taper that prevents the knife from cutting too deep into the leather.
The blade will also have a “pin” to insert and lock the blade into place. Some of these pins may be threaded for those that screw on. The body of the tool, also known as the barrel, houses the bearing and knife pin. Barrels are created by drilling out the center of a material, for example, brass, metal, wood, stacked leather, or other materials.
The outside of the barrel is then shaped to provide the best fit. After being rounded to the correct size, a knurling can be added to the barrel to provide a better grip. For assembly, the ball bearings are placed into the barrel with a yoke to keep the finger holder from spinning. The blade is inserted into the barrel and locked into place with a small screw or by threads.
Swivel Knife Costs
The introductory price of swivel knives will be around $15. There may be a few issues with the knife at this price point, but it can get the job done. The blade may be dull and need sharpening, the barrel may be too large, or the bearings may be too stiff to swivel smoothly.
As the price increases, swivel knives improve functionally and ergonomically. The biggest changes are different barrel sizes and a smoother spinning action. Swivel knives become more custom workpieces at the highest price points of $80+, utilizing more decorative material or incorporating intricate engravings.
Alternative Options to a Swivel Knife
If you find yourself without a swivel knife, some unique alternatives can be used. Any craft knife can be used, but controlling the depth will be necessary as it is easier to cut through the leather entirely. Al Stohlman and Bob Brown, pioneers of leather crafting, used sharpened shop tools for their carving. A screwdriver, or even a nail, was sharpened and used for carving leather.
Experienced Tips for Working With a Swivel Knife
- Ensure the leather has been thoroughly cased before attempting to carve.
- Test multiple barrel and blade sizes to find what works.
- Use less pressure and multiple passes to control the blade around tricky designs.
In this really interesting video, Jim Linnell from Elktracks Studio shows some of the amazing swivel knives Tandy has made:
My Personal Research with a Swivel Knife
To create the best results with a swivel knife, I tested the differences when using one on dry, wet, and cased leather. My goal was to see how easily it was to use the swivel knife on the leather and how the final result looked.
I started this test with completely dry vegetable tanned leather. While I know it is necessary to wet leather before using a swivel knife, I was curious why. I quickly found out why when attempting to use the knife. The knife did not want to pass through the leather easily. Too much pressure, and I found myself snagged, too little, and it felt like the knife was bouncing off the surface.
While I could make cuts throughout the leather, and there was little to no damage on the surface, it was not ideal. Hours after cutting, the lines started to close up and almost faded. While the cuts were still present, the sides were not pushed apart to create the ideal valley.
For wet leather, I used a traditional wet-and-go method. For this to work, I took a sponge, dipped it in water, and rubbed it on the area I was about to carve. I knew using soaking wet leather would result in poor-quality carving, but treating each area as I went worked better than expected. The leather was much more reactive to the swivel knife, cutting the leather with much less effort than dry leather.
I felt the knife snag on very tight turns, but otherwise, it was an enjoyable method. However, needing to apply water on areas made the results inconsistent at best, as some areas would receive more water than others. When dried, the cut marks were clear, and the inconsistencies were harder to see. Overall the method worked, and I can see why crafters choose to use this when time is restrictive.
After previously testing cased leather for stamping, I had the highest hopes for this method. Casing leather is the method of soaking it in water until the air bubbles stop, then wrapping the leather in plastic to be left to dry overnight. Using this method to carve leather was no different than stamping. The entire process of using the swivel knife was buttery smooth.
I felt as if there was almost no resistance when carving the leather, with my pressure well under control. Even the tightest of curves provided little resistance. Once the leather was completely dried I was once again blown away by the difference. While the wet leather left good clean lines, the cased leather looked even better. Every line was clearly defined, and the depth created was much greater than the simply wet leather.
To achieve the best results when using a swivel knife, it is important to wet the leather. Dry leather makes it difficult to cut and control the pressure and closes up the most. When deciding to case the leather or not, time is the most significant factor. While cased leather produces a much better result, it takes overnight to set up. When time is limited, dampening the areas before carving the leather will still produce good results.
Swivel Knife Care and Maintenance
How to Clean a Swivel Knife
Swivel knives can be cleaned using only water and a cloth. Dampen the cloth before rubbing any unwanted debris off the tool. Afterward, the tool must be completely dried before storing it to prevent rust from developing. Isopropyl alcohol can be used diluted with water to clean tougher messes. Apply this mixture onto a clean cloth before rubbing the surface.
How to Maintain a Swivel Knife
As swivel knives are used, they must consistently be polished to provide the best results. A leather strop with a polishing compound can be used to keep the blade sharp. It is best to polish the blade after every project to keep it at its best. If the blade becomes too dull, whetstones or sandpaper may be used to sharpen the knife. It is important to keep a consistent angle when sharpening the blade.
How to Store a Swivel Knife
Swivel knives need to be covered when they are stored. This protects the blade if the tool is dropped and prevents any danger of being cut by accident. In addition, it is important to ensure the tool is dry before putting it away. A moist swivel knife can develop rust, ruining the tool. Stored swivel knives should be kept in dry environments with the blade covered and ideally out of the way of the working area.
Helpful Swivel Knife Insights
What is a swivel knife used for?
Swivel knives are used to carve designs into leather. From flowers to animals, the swivel knife is like a paintbrush for leather. The tool provides depth to any design and can also be used as an outlining tool to highlight stamps.
How do you strop a swivel knife?
To strop a swivel knife, apply a polishing compound to the strop. Remove the knife when possible and match the angle by placing the blade onto the strop with the tip facing away from you. Lift the blade slowly until it is flush with the strop. Keep this angle and pull the blade along the strop to begin polishing it. Repeat for the other side of the blade to keep it sharpened.
Do you wet the leather before using a swivel knife?
Yes, much like stamping, leather must be wet before a swivel knife is used. Vegetable tanned leather should be cased overnight to produce the best results. Leather that is too dry may cause the swivel knife to jerk around when cutting. Leather that is too wet may cause unsightly wrinkles as it pulls the leather too much.
Does a swivel knife cut the leather?
Yes, a swivel knife cuts the leather, but only the surface. The blade’s shape prevents the leather from cutting through or excessively deep into the leather. These cut marks create a valley that adds depth when using a swivel knife.
- Swivel knives come in a variety of sizes and blade types.
- Vegetable tanned leather must be wet or cased before attempting to carve with a swivel knife.
- Swivel knives allow creative designs to be added to the leather’s surface.
Swivel knives are one of the most iconic tools in leather craft as it allows creativity when working with leather. They are specialty tools with limited uses but are invaluable when carving leather. If tooling leather is what you enjoy as a crafter, a swivel knife is a must-have tool.
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