e total length is only 9 inches. For lengths longer
or shorter than twelve inches, the taper per inch should be found first;
this is then multiplied by the _total_ length of the work (not the
length of the taper) which gives the taper for that length, and one-half
this taper is the amount to set over the center. For example, the taper
per inch of part _B_ equals 1 inch divided by 12 = 1/12 inch. The total
length of 9 inches multiplied by 1/12 inch = 3/4 inch, and 1/2 of 3/4 =
3/8, which is the distance that the tailstock center should be offset.
In this example if the taper per foot were not known, and only the
diameters of the large and small ends of the tapered part were given,
the difference between these diameters should first be found (2-1/2-2 =
1/2); this difference should then be divided by the length of the taper
(1/2 / 6 = 1/12 inch) to obtain the taper per inch. The taper per inch
times the _total_ length represents what the taper would be if it
extended throughout the entire length, and one-half of this equals the
offset, which is 3/8 inch.

=Example of Taper Turning.=--As a practical example of taper turning let
us assume that the piece A, Fig. 4, which has been centered and
rough-turned as shown, is to be made into a taper plug, as indicated at
_B_, to fit a ring gage as at _C_. If the required taper is 1-1/2 inch
per foot and the total length is 8 inches, the tailstock center would be
offset 1/2 inch.

[Illustration: Fig. 4. Taper Plug and Gage]

To adjust the tailstock, the nuts _N_ (Fig. 3) are first loosened and
then the upper part _A_ is shifted sidewise by turning screw _S_. Scales
are provided on some tailstocks for measuring the amount of this
adjustment; if there is no scale, draw a line across the movable and
stationary parts _A_ and _B_, when the tailstock is set for straight
turning. The movement of the upper line in relation to the lower will
then show the offset, which can be measured with a scale.

When the adjustment has been made, nuts _N_ are tightened and the part
to be turned, with a dog attached, is placed between the centers the
same as for straight turning. The taper end is then reduced by turning,
but before it is near the finished size, the work is removed and the
taper tested by inserting it in the gage. If it is much out, this can be
felt, as the end that is too small can be shaken in the hole. Suppose
the plug did not taper enough and only the small end came into contact
with