Читать книгу Mike Darlow's Woodturning Series: Useful Woodturning Projects - Mike Darlow - Страница 29

As figure 2.3 shows, turners can readily produce small skews by grinding down skews with wider-than-required blades, or by locking bits into stiff shafts. Figure 2.4 explains how I produce the latter type.

Skew chisel blades with circular cross sections are obviously stiffer than thinner, essentially rectangular blades with the same effective cutting-edge length. However when rolling tiny beads with a circular-bladed skew, the blade may have to be traversed “backwards” along the toolrest.

Figure 2.3 Two small, stiff-bladed skews, top 7-mm-wide, bottom 3-mm-wide.

Figure 2.4 Making a turning tool with a bit housed in a stiff shaft.

Here I’ve axially gripped in a scroll chuck a suitable length of steel cut from a 10-mm-diameter mild steel bolt or machine screw. After scraping a small axial recess in the right-hand end of the shaft to accurately center the drill tip, I bored a hole about 25-mm long. The drill’s diameter should be such that the bit will fit snugly within the hole.

For a tiny skew, I use the unfluted part of a HSS twist drill as the bit. For tiny gouges, the bit can be cut from a too-slender gouge shaft such as that shown next to the bedway. I use the edge of a grinding wheel to cut off a bit length.

To lock the bit into the bored hole you could use a suitable adhesive. Instead I usually just use a crisp blow with a hammer on the end of the shaft as shown on the right-hand gouge in figure 2.12.