Every woodturner can likely recall a moment early in their journey when a tool, intended for precision, seemed to have a mind of its own. For many, this nemesis tool is none other than the **skew chisel**. It is often perceived as the most challenging of the primary woodturning tools, yet its mastery unlocks an unparalleled level of finish and efficiency. The frustration of constant catches, gouges, and less-than-perfect surfaces can be disheartening. However, as demonstrated in the insightful video above by master woodworker Rob Cosman, the skew chisel is not merely a tool of difficulty; it is a gateway to truly exceptional results.
Indeed, the pursuit of a flawless finish, achievable with minimal sanding, is a goal shared by nearly all woodturners. While other tools might rough out a shape or create specific profiles, the unique shearing action of a properly used **skew chisel** often leaves a surface that appears almost polished directly from the lathe. This article will expand upon the foundational principles introduced in the video, delving deeper into the nuances of sharpening, tool mechanics, and practical application that transform this challenging instrument into a powerful ally in your woodworking shop.
Understanding the Skew Chisel: The King of Finish
The **skew chisel** is frequently categorized alongside the parting tool, scraper, and bowl gouge as one of the four essential woodturning implements. Yet, its distinct design—a flat, rectangular cross-section with a bevel ground at an angle to the long edge—sets it apart. Unlike scrapers that tear wood fibers, or even gouges that can leave distinct marks, the skew chisel is engineered for a “shearing” cut. This means that instead of forcibly removing material head-on, it slices through the wood fibers at an angle, much like a hand plane shaves a board. This action not only removes wood efficiently but, crucially, compresses and polishes the remaining surface, leading to an incredibly smooth finish. A good skew chisel finish can often bypass coarser grits of sandpaper, sometimes moving directly to 220-grit or even higher for a quick buff.
Historically, prominent figures in woodturning, such as Dale Nish—acknowledged by Rob Cosman as one of the best-known woodturners of the last 50 years—have emphasized the importance of the skew chisel for spindle work and furniture components. His teachings, and those of many others, often centered on the precision and surface quality attainable with this tool, making its proper use a benchmark for skill.
Why the Skew Chisel is Difficult to Master
Despite its advantages, the **woodturning skew chisel** is widely considered the hardest tool for beginners. This difficulty primarily stems from the precise control required over three critical variables simultaneously: the angle of approach, the angle of the bevel to the wood, and the tool’s rotation along its axis. A slight miscalculation in any of these can lead to a “catch,” where the tool digs abruptly into the wood, often leaving a significant divot or even causing the workpiece to come loose. Such experiences can be intimidating, leading many new turners to shy away from the tool altogether in favor of less demanding scrapers.
However, the reward for perseverance is substantial. A properly sharpened and skillfully applied **skew chisel** can dramatically reduce post-turning work, saving considerable time and effort in sanding. Moreover, the clean, crisp lines and buttery smooth surfaces it creates elevate the quality of turned pieces, a testament to the turner’s growing expertise.
The Cornerstone of Precision: Sharpening Your Skew Chisel
As highlighted in the video, effective use of a **skew chisel** begins with meticulous sharpening. A dull skew chisel is not merely ineffective; it is dangerous, prone to tearing wood and increasing the likelihood of catches. The goal is always a razor-sharp edge with a consistent, flat bevel.
Optimal Bevel Angles and Geometry
While specific angles can vary based on personal preference and the type of wood being turned, a common recommendation for a **woodturning skew chisel** is a bevel angle between 20 to 30 degrees. Rob Cosman’s Henry Taylor skew chisel, with a 3/8-inch wide bevel on a 1/4-inch thick blade, implicitly suggests an acute, rather than obtuse, angle, which is essential for a clean shearing cut. A more acute angle (closer to 20 degrees) excels in softwoods, while a slightly less acute angle (closer to 30 degrees) provides greater durability for hardwoods.
Crucially, a flat bevel is often preferred over a hollow grind (concave shape) produced by the face of a conventional grinding wheel. A flat bevel offers more consistent contact with the wood, improving stability and control during the cut. This consistency is a primary reason why flat-grinding methods are often advocated by seasoned turners.
Sharpening Methods Explored
The video demonstrates several approaches to sharpening, each with its own advantages and accessibility:
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Disk Sander Method: Considered by Rob Cosman as the “easiest way,” the 16-inch disk sander provides a large, flat abrasive surface. With a 120-grit disk, it allows for maintaining a perfectly flat bevel by resting the chisel in a jig or simply using the table to support the angle. The large surface area helps dissipate heat, reducing the risk of overheating the tool, which can ruin its temper.
- Benefit: Excellent for maintaining a flat bevel and rapid material removal.
- Consideration: A 16-inch disk sander is a specialized and less common tool in most home shops.
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Bench Grinder with CBN Wheel: This method is far more common. The use of a Cubic Boron Nitride (CBN) wheel is a significant upgrade over traditional aluminum oxide wheels. As mentioned, CBN wheels, such as the 80-grit variant used, are abrasive on multiple sides and generate much less heat. This is paramount when grinding steel tools to prevent bluing or annealing the edge. By using the side of the wheel rather than the face, a flat grind can be achieved, albeit with more manual control required compared to the disk sander.
- Benefit: Superior edge quality and less heat generation compared to standard grinding wheels. More accessible for many woodturners.
- Consideration: Requires careful hand-eye coordination to maintain a consistent angle and avoid hollow grinding. Overheating is still a risk if not careful, hence the “in and off” technique.
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Diamond Plate (Hand Sharpening): For those without power grinders or needing touch-ups, a diamond plate, such as the double-sided Trend stone (300-grit and 1000-grit) shown, is invaluable. This method provides ultimate control and is ideal for refining an edge or removing a burr. While more laborious for significant regrinding, it is excellent for maintaining a keen edge.
- Benefit: Portability, precision control, no heat generation.
- Consideration: Slower process for substantial material removal; requires a steady hand and practice with short, controlled strokes to avoid rocking the tool.
Regardless of the method, the final step involves removing the burr (a thin wire edge) created during grinding. A simple piece of scrap wood, as demonstrated, can effectively break off this burr, leaving a clean, sharp cutting edge. It is interesting to note that Rob Cosman suggests that for lathe work, the power of the lathe combined with a decent grind often negates the need for extensive honing beyond 120-grit or 80-grit, a testament to the aggressive nature of turning.
Setting Up for Success: Lathe and Tool Considerations
Before any wood is transformed, the lathe and workpiece must be properly prepared. The video emphasizes several crucial setup elements:
Lathe Stability and Speed
A heavy, stable lathe, such as the General brand model used by Rob Cosman, is highly advantageous for spindle turning. The increased mass minimizes vibration, which is critical for achieving smooth cuts and reducing chatter, especially with a sensitive tool like the **skew chisel**. While many beginner lathes require manual pulley changes for speed adjustments, modern or modified lathes with variable speed controls offer immense flexibility, allowing the turner to fine-tune RPMs for different wood types and cutting operations. For small diameter stock, a higher RPM is generally preferred, as it increases the effective cutting speed of the tool.
Tool Rest Position and Ergonomics
The tool rest’s height should be set just slightly above the center of the workpiece. This provides optimal leverage and ensures the tool’s cutting edge engages the wood effectively. Furthermore, positioning the tool rest as close to the wood as safely possible maximizes leverage, giving the turner better control over the tool’s presentation. It is also a good practice to ensure the tool rest’s surface is smooth, preventing catches or snags as the tool slides along it.
Skew Chisel Selection and Preparation
Rob Cosman showcases four sizes: 1-inch, 3/4-inch, 1/2-inch, and 1/4-inch. His personal preference for the larger 1-inch or 3/4-inch skew chisels stems from the “extra reference surface” they provide. This larger surface area can aid in stability for beginners. Reputable brands like Henry Taylor, Sorby, or Craft Supplies offer high-quality chisels. A crucial tip, often overlooked, is rounding over the sharp corners of the chisel. These corners, if left sharp, are notorious for digging into the wood and causing unsightly marks or catches. A belt sander or file can quickly achieve this rounded profile, greatly improving the tool’s user-friendliness.
Mastering the Shearing Cut: Effective Skew Chisel Techniques
The core philosophy of the **skew chisel** lies in its shearing action. Understanding this principle is fundamental to overcoming the tool’s initial challenges and unlocking its potential for flawless finishes.
Shearing vs. Scraping: The Fundamental Difference
The video clearly illustrates the contrast between a shearing cut and a scraping cut. A scraping tool, such as a carbide scraper, simply presses its edge against the wood, tearing fibers and producing dust. While easy to use, it leaves a rough, torn surface that requires extensive sanding, potentially altering the intended profile. In stark contrast, the **skew chisel**, when properly applied, slices through the wood fibers, producing thin, ribbon-like shavings and a remarkably smooth surface. This fundamental difference is why a skew chisel is often favored for fine spindle work where surface quality is paramount.
The Bevel-Supported Cut: Your Safety Net
The secret to avoiding catches with a **skew chisel** is the bevel-supported cut. The video explicitly advises working on the lower half, or ideally the lower third, of the tool’s bevel. When the bevel is correctly registered against the rotating wood, it acts as a fulcrum and a guide, preventing the cutting edge from digging in too deeply. The actual cutting edge is then rotated into the wood just enough to take a controlled shaving. If the tool is inadvertently allowed to ride above the halfway point of the bevel, a catch is almost inevitable, as the tool loses its support and dives into the workpiece.
Imagine the process like using a hand plane: the sole of the plane (analogous to the bevel of the skew) registers against the wood, guiding the blade at a consistent depth. With the skew chisel, this continuous bevel contact ensures a controlled, predictable cut. This understanding underscores the importance of softwoods like Northern white pine, basswood, or poplar for practice. Their forgiving nature minimizes the dramatic effects of an accidental catch, building confidence without excessive fear.
Body Mechanics and Tool Control
The way the tool is held and moved is also crucial. Rob Cosman, echoing the advice of renowned turners like Richard Raffan, suggests a relaxed grip. Squeezing the tool too tightly diminishes the turner’s ability to “feel” what the tool is doing as it interacts with the wood. A relaxed grip allows subtle vibrations and resistance to be transmitted to the hands, providing vital feedback for micro-adjustments.
The lead hand guides the tool on the tool rest, while the off-hand primarily provides leverage from behind the tool rest. This creates a stable platform, allowing the cutting action to be smooth and controlled. Importantly, the turner’s focus should be on the overall profile of the turning, observing the top surface where the wood is being shaped, rather than fixating solely on the point of contact between the tool and the wood. This broader perspective helps to maintain consistent curves and lines, preventing unintentional dips or bulges.
Practical Exercises for Developing Skill
The video implicitly suggests starting with simple cylindrical shapes to get the wood round. This initial step, where all “flats” are removed, provides a consistent, round surface for practicing the bevel-supported cut. Once this foundational skill is acquired, turners can progress to more complex exercises such as:
- V-cuts: Creating a sharp, inward V-groove. This requires rotating the **skew chisel** into the wood, using either the “heel” or “toe” of the chisel.
- Beads: Forming convex, rounded profiles. This often involves a combination of push cuts and drawing cuts, smoothly rolling the skew chisel to create the desired curve.
- Coves: Carving concave, inward curves. These can be particularly challenging but demonstrate the tool’s versatility.
- Planing Cuts: Using the entire flat edge of the skew to smooth long, straight sections, much like a hand plane.
Each exercise builds upon the core principle of maintaining bevel contact, managing the cutting edge, and sensing the interaction between tool and wood. With consistent practice on forgiving softwoods, the elusive mastery of the **skew chisel** can indeed be attained, transforming potential frustration into profound satisfaction.
Let’s Talk Skew: Your Turning Questions Answered
What is a skew chisel and what is it used for in wood turning?
The skew chisel is a unique woodturning tool designed to make a ‘shearing’ cut. It is primarily used to achieve an exceptionally smooth, almost polished finish on turned wood, often minimizing the need for sanding.
Why is the skew chisel often considered difficult for beginners?
It’s considered difficult because it requires precise control over its angle, bevel, and rotation simultaneously. Mistakes can easily lead to a ‘catch,’ where the tool digs into the wood.
What is the most important technique to avoid catches when using a skew chisel?
The most important technique is the ‘bevel-supported cut.’ This means keeping the lower half or third of the tool’s bevel firmly registered against the rotating wood, which acts as a guide and prevents the cutting edge from digging in.
How important is sharpening for a skew chisel?
Sharpening is extremely important; a razor-sharp edge with a consistent bevel is essential for effective and safe use. A dull skew chisel is prone to tearing wood and causing dangerous catches.
What kind of wood is best for beginners to practice with a skew chisel?
Beginners are advised to practice on forgiving softwoods like Northern white pine, basswood, or poplar. Their softer nature makes accidental catches less dramatic, helping to build confidence.