Fig. 1.
Fig. 1.
Fig. 2.
Fig. 2.
Fig. 3.
Fig. 3.
Fig. 4.
Fig. 4.
Fig. 5.
Fig. 5.
Fig. 6.
Fig. 6.
It is evident that the variations producible by working intersecting spirals and waved lines are very numerous, and these may be additionally varied by the combination of eccentric and spiral movements.
The following six patterns are re-engraved from Valicourt's Hand Book, which is almost identical with that of Bergeron. They were not engraved in time to be inserted under the head of eccentric chuck work. The notation and description annexed is from a manuscript book kindly lent to the writer by an amateur. "Bed-plate," 4 deg., must be taken to mean that the work is shifted (on one of the beds of the chuck) four of the marked divisions for eccentricity, counting from the axial line of the mandrel.
"Slide rest, 4 deg.," means that the cutting tool is moved four corresponding divisions in its bed for radius of the circle to be cut; and so throughout.
"4 *," means four times repeated.
The cutting tools, unless otherwise expressed, are double angled, and "25 cutting tool," means 25 deg. of cutting edge.
Holtzapffel's scale of divisions is
Holtzapffel's scale of divisions is
The scale used in Valicourt iswhich is that here quoted.
The scale used in Valicourt is
which is that here quoted.
If bed-plate and slide rest are both equally diminished at each cut, a shell results, with the close part internal. If bed-plate is increased and slide rest diminished, the close part of the shell is external.
SPECIMEN I.—Tools 25, 32, 36; Click-plate 96 or 288.
SPECIMEN II.—Tools 28, 36; Click-plate 288.
( 1 " 18 " )
( 1 " 4 " )
(15 done 4 missed)
( 1 " 4 " )
(1 " 18 " )
(1 " 4 " )
From B to here, border, if with 96 click-plate, not good-looking; tool a boring-bit.
(1 " 5 " )
(1 " 1 " )
(1 " 1 " )
(5 " 1 " )
(1 " 1 " )
(1 " 5 " )
(1 " 1 " )
(7 " 1 " )
SPECIMEN III.—Click-plate 96.
SPECIMEN IV.
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):—
SPECIMEN V.—Catherine wheel; tool 28.
The ground grailed by concentric circles contiguous to each other. The arcs by fours, all of same radius.
(Repeat at three next divisions.)
SPECIMEN VI.—Tools 28, 36; Click-plate, 288.
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 theEnglish 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 theEnglish Mechanic.[24]
[24]See Appendix.
[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 theEnglish 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.