Smithy Midas 1220 XL - Manual (Page 67)

Figure 12.6 Tapers cut with the compound rest are
usually short, abrupt angles.
Figure 12.7 In setting over the tailstock, the lathe centers move
from their parallel position with the tool’s transverse travel.
To offset the tailstock, adjust the two base-locking bolts (Figure5.8). To offset to the right,
loosen the right adjusting bolt and tighten the left. To offset to the left, loosen the left
adjusting bolt and tighten the right.
You can turn long, gradual tapers by setting over the tailstock, but take care. Your
computations must be nearly perfect, because an error will spoil your work.
The distance of tailstock set-over needed to machine any given taper depends on three
factors:
• The differential between the finished diameters of the extreme ends of the taper
• The length of the taper in relation to its extreme diameters, if the entire shaft
is to be tapered
• The ratio between the length of the shaft (or work between centers when you’re
tapering only part of the shaft).
When the taper extends the entire length of the workpiece, tailstock set-over should
equal half the difference between the finished diameters of the ends (Figure 12.8). When
a taper extends only part of the length of the shaft, divide the total shaft length by the
length of the portion to be tapered. Then multiply the resulting quotient by half the
difference between the extreme diameters of the finished taper.
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Lathe Turning