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Detail gouges are extensively used with both axially and transversely grained workpieces. As figure 2.1 shows, smaller sizes are commonly fitted with blades which flex. To overcome this, I’ll first consider detail gouge blade cross sections, then how to grind their noses.

Figure 2.5 shows the ideal detail gouge cross section. Before HSS displaced carbon tool steel, for cutting deep narrow coves, narrow blades with cross sections similar to that shown in figure 2.6 were produced by forging. The resulting blades were rotationally unstable, required more complicated manipulations, and in some cases were still not stiff enough.

Properly-stiff, small-fluted HSS gouges could be created by manufacturers producing detail-gouge blades with cross sections similar to that shown in figure 2.7. I’m not aware that such gouges are currently manufactured. Turners can however produce satisfactory alternatives by:

1. grinding down the nose of a suitable bowl gouge with an effectively small flute radius (this is detailed on pages 15 and 16). Manufactured bowl gouges usually have U- or parabola-shaped flute cross sections and high flanges. Their blades are therefore considerably stiffer than those of detail gouges with the same blade diameter. Also the cross section of the bottom of most bowl gouge flutes is close to semicircular

2. cutting a too-slender blade shorter—you then have the option of using the off-cut as a bit

3. cutting a slender blade into short lengths (bits) which are fixed into stiff shafts as explained in figure 2.4.

Figure 2.5 The optimum, rotationally-stable detail gouge cross section. The smaller the lever arm between the force exerted by the shaving and the upward reaction force exerted by the toolrest, the smaller the tool’s tendency to unexpectedly rotate and catch. This lever arm is small when there is a semicircle of steel below the base of the flute. Because most cutting is performed by the cutting edge’s shoulders, the lever arm is even smaller if the semicircle is slightly flattened (indicated by the blue, dashed line).

Obviously the stiffness of a blade with this cross section is related to its width.

Figure 2.6 A blade cross section which is somewhat stiffer than one with the same flute radius but the figure 2.5 cross section. However this deeper blade cross section results in a longer lever arm between the two forces and therefore greater rotational instability.

Figure 2.7 A rotationally-stable, stiff blade cross section with a small flute radius. To improve its ability to cut deep, narrow coves, the nose’s width must be reduced by grinding back the flanges as shown in figures 2.10 and 2.11.

Figure 2.8 Top, a 19-mm-wide detail gouge with a ladyfinger nose; bottom, a gouge with a fingernail nose.