Many of today’s bowl gouges are made by milling round bar stock with a milling cutter to create the flute. These milling tools come in many shapes, which result in various flute profiles in woodturning tools. How these tools are ground adds further choices for the final shape of the gouge. The combination of bowl gouge flute shape and grinding profiles leads to a vast array of possibilities for how a bowl gouge looks and performs. Once you find what works for you, you’ll have the perfect tool for your style. Below, I will explain more about this topic and share my thoughts on the subject.
| All regular Carter and Son bowl gouges have a V-shaped flute. | All Carter and Son Mike Mahoney gouges have a parabolic flute. | The CST 5/8″ gouge above is the only U-shaped tool we carry. | All Robust bowl gouges have a parabolic flute. |
Flutes in bowl gouges are deep but they should retain a certain amount of mass at the bottom of the flute to keep the tool strong. Most bowl gouges feature one of three primary flute shapes:
U-Shaped Flutes
These flutes are broader at the bottom, which gives the nose of the tool a longer, straighter cutting edge. This shape is highly effective for making smooth finishing cuts, particularly on dry or highly figured woods, because it cleanly slices through irregular fibers and may help minimizes tear out. U-shaped flutes are also considered the best shape to use if you prefer a traditional grind. This flute shape produces a naturally flat wing cutting edge while grinding the wing without requiring additional tool manipulation. If you want a convex wing on a V-fluted gouge then you will have to rock the tool back and forth while grinding the wing cutting edge.
V-Shaped Flutes
V-shaped flutes are a popular deep-profile choice for bowl turning. They pair exceptionally well with swept-back wing grinds (such as the Irish or Ellsworth grind), making them highly versatile for heavy roughing, pull cuts, and shear scraping. This bowl gouge flute shape naturally produces a flat wing cutting edge during grinding without requiring additional tool manipulation. If you prefer a convex wing on a V-fluted gouge, you will need to manually rock the tool back and forth while grinding the wing.
Parabolic Flutes
Alternatively, many bowl gouges utilize a parabolic flute. The unique geometry of these flutes allows the tip of the gouge to slice into the wood while the wing simultaneously produces a peeling action. Because of its shape, the parabolic flute produces a natural convex curve on the wing cutting edge with a simple, direct grind—no extra movement required.
Observations on Gouge Flute and Grinding Geometry
A gouge with a U-shaped flute naturally tends to produce a flat wing during grinding. As seen in typical profiles, the U-shaped bowl gouge features straight wings that remain parallel and widely spaced, appearing vertical when viewed from the end. This configuration means the grinding profile must “wrap” around the top edge to complete the cutting surface. While this straight-wing shape is excellent for bulk material removal, the “wrap” requires more tool rotation for effective shear scraping. In my experience, the wide nose at the bottom of a U-shaped flute can be somewhat prone to catches; however, these make exceptional bottom bowl gouges when ground with a steep 60° to 65° bevel and nearly zero rake, though I typically sweep the left wing back to improve safety.
Similarly, bowl gouge flute shaped like a V tend to grind a flat wing, though the wings spread further apart due to the flute’s geometry. This spread reduces the degree of “wrap” on the upper edge. While it is a versatile tool, it is not my preferred choice. A V-fluted gouge is particularly well-suited for a 40/40 grind, as it provides a flat wing surface ideal for heavy stock removal, much like a scraper. The 40° bevel is advantageous for entry cuts because the handle does not need to swing as far as with a 50° or 55° bevel, though it may struggle when navigating the interior of deep bowls.
The parabolic fluted gouge is my personal favorite, specifically when paired with a swept-back wing (akin to the Ellsworth or Irish grind) and a 55° bevel angle. I adopted this grind during a transformative class with Al Stirt in 2008, and it was a significant turning point for me. This has remained my primary configuration for many years. With a parabolic flute, a convex wing is naturally produced during grinding—whether using a Tru-Grind system or another jig. This convex wing allows for more controlled contact, ensuring only a small portion of the cutting edge engages the wood at any time. The narrow nose further limits contact, providing exceptional control for both rapid waste removal and fine detailing cuts.
Be sure to read on about ‘Bowl Gouge Grinds‘ to put the pieces together so that you can understand the relationship of the grind with the flute geometry.
If you have comments please let me know (see comment or email button below) and I will answer and share what I learn.