The centre of this is a star of six curved rays, described by fixing
the cutter at the centre and turning the mandrel by hand through so
many divisions--for convenience so many 48ths of the circumference.
These rays are marked by B. (The segment stop is constructed for this
very kind of work, and is to be used in the present case):--
Bed-plate. Slide rest. Arcs done for star.
5 B 5 6 (12/48ths of the circle)
5 B 5 12 (11/48ths " )
5 B 5 12 (10/48ths " )
5 B 5 12 ( 8/48ths " )
14-1/8 5 24 (2 done, 2 missed)
19-3/4 1/2 96
24-1/4 4 32
29-1/2 2-1/2 32 (intersecting)
30-1/2 2 32
SPECIMEN V.--Catherine wheel; tool 28.
The ground grailed by concentric circles contiguous to each other. The
arcs by fours, all of same radius.
Bed-plate. Rest. Arcs done.
0 1/2 3/4 1-1/4 &c. (for grailing)
B 30 30 12 (16/48)
(Repeat at three next divisions.)
SPECIMEN VI.--Tools 28, 36; Click-plate, 288.
Bed-plate. Rest. Number.
1-1/4 1 8 done
B 12 12 12-7/48 (to meet next circle)
4-3/8 17 24
30 1/2 12
29-1/2 1 12
(On same radius as the last, and surrounding it.)
29 1-1/2 12
28-1/2 2 12
28 2-1/2 12
27-1/2 3 12
27 3-1/2 12
26-1/2 4 12
23-1/2 1 12
(3 done, 21 missed between last, or if click-plate 96.)
25 1 12 (between last)
Although in the matter of beauty the patterns here given are by no
means comparable to many others, especially to some lately published
from blocks cut by Mr. George Plant, for the _English Mechanic_;
they are, by their comparative simplicity, well selected to give the
learner a good idea of designing and working with the eccentric chuck.
It is not, indeed, proposed by the writer to multiply patterns, as
mere copying of such is of small interest to those who are really
endued with taste and skill; and the variations producible by
combinations of different numbers of divisions of the click-plate and
slide rest are of such infinite number, that printed designs of a
score or two would not serve to teach the nature of this work better
than the half dozen now before the reader. When a new chuck, indeed,
is brought out, it is well to give a few specimens of its work, to
show the possible purchaser its value as a means of ornamentation and
the extent of its capabilities; but when these are understood, the
purchaser had much better design for himself, instead of becoming a
lazy imitator and copying patterns laid down by others. Details of
designs that are presented in a tabular form remind us sadly (for we
are married) of the old "_knit one, drop two_," "_purl_" or some such
mysterious and, to us, detestable jargon wherewith ladies were, or
are, wont to worry the ears of mankind.
* * * * *
The chuck of Professor Ibbetson, and the elliptic cutting frame
of Captain Ash, are not introduced here, partly because this work
has reached its intended limit, and partly because the inventors
themselves have published separate works entirely devoted to a
description of the arrangements and capabilities of their respective
chucks. A brief notice is appended of Plant's geometric chuck,
contributed by the inventor to the pages of the _English Mechanic_.[24]
[24] See Appendix.
* * * * *
The author now concludes his pleasant labours, the result of which
is contained in the preceding pages. These labours have been
lightened, and the work itself benefited, by several kindly-written
remarks received from various readers of the _English Mechanic_,
while the articles were in course of production in that paper.
Criticisms and suggestions also came to hand in which no such kindly
feelings appeared. These also have, nevertheless, had an equal share
of attention, and where they appeared to be of value they have
been turned to profit, and have resulted in various more or less
important alterations and additions. "The Lathe and its Uses," thus
re-arranged and modified, must now take its chance in the world with
other productions of a similar character; and the writer hopes it
may suffice to help those who need such assistance, and may be well
received by others who though able to walk alone may yet cherish a
kindly feeling for the friendly walking-stick.