A New System Or Decimal Gages Or Measures

For Sheet Metals, Wires, and Small Manufactured Articles Generally.

Including the exact decimal values of the gages now principally used for these purposes in the Mechanical Arts.

This paper is extracted from the Appendix to Vol. II. of "Turning and Mechanical Manipulation," by Charles Holtzapffel. Pamphlet 8vo, in wrapper, price 1s.

Printing Apparatus For The Use Of Amateurs

Containing full and practical instructions for the use of Cowper's Parlour Printing Press, also the description of larger presses on the same principle, and various other apparatus for the Amateur Typographer.

The pamphlet contains likewise, numerous specimens of plain and ornamental types, brass rules, checks, borders, ornaments, corners, arms, etc. etc. Third Edition, greatly enlarged. 8vo, cloth, Price 2s. 6d.

Holtzapffel And Co's General Catalogue

Of Lathes, Tools, and Instruments Employed in the Mechanical Arts generally.

Stereotype Edition. 1849. 8vo. pp. 72, Price 6d., or free by Post, 1s. 4d.

Brief Account Of Ibbetson's Geometric Chuck

H. & Co. beg to announce that they have purchased the remaining copies of the pamphlet written by the late J. H. Ibbetson, Esq., entitled "A brief Account of Ibbetson's Geometric Chuck, manufactured by Holtzapffel & Co., with a Selection of Specimens illustrative of some of its Powers." - Pamphlet 8vo., in coloured wrapper, Price 5s.

Elliptical Cutting Frame

Elliptical Cutting Frame 300153

MANUFACTURED BY

HOLTZAPFFEL & CO.,

64, CHARING CROSS, and 127, LONG ACRE, LONDON.

THE Elliptical Cutting Frame, invented by Captain Ash, H.E.I.C.S., is employed in the lathe, for ornamenting turned surfaces with elliptical figures, after the same general method that the eccentric cutting frame is employed for producing circular figures on similar surfaces; viz., the object to be ornamented is fixed on the lathe mandrel, and motion is given to the tool by the Elliptical Cutting Frame, which is fitted to the receptacle of the sliding rest, and driven by a band leading from the overhead motion.

The Elliptical Cutting Frame is capable of producing ellipses of all proportions, from a right line to a circle, according as it may be adjusted; and the ellipses may be arranged either in circular order by the employment of the division plate, or in rectilinear order by the motion of the sliding rest; or the two movements may be combined at pleasure. An almost infinite variety of patterns of a highly ornamental character will, therefore, he produced by the elliptical movement alone. In addition to which, the instrument is adapted to produce epicycloidal patterns of 4 loops, similar to those produced in the geometric chuck; these looped figures may likewise be made in all proportions, and be placed in any positions.

Pattern 1.

Elliptical Cutting Frame 300154

Pattern 2

ELLIPTICAL CUTTING FRAME.

ELLIPTICAL CUTTING FRAME.

Pattern 3.

Elliptical Cutting Frame 300156

Pattern 4.

Elliptical Cutting Frame 300157

From these comprehensive powers of the Elliptical Cutting Frame, it results that any desired arrangements may be produced of circles, ellipses, right lines, or 4-looped figures: the instrument is, therefore, a most desirable addition to all lathes for ornamental turning, and, if required, its powers may be still further increased by the addition of other epicycloidal patterns, or by combining its movements with those of the eccentric chuck or other apparatus for ornamental turning.

General Remarks on the Action of the Elliptical Cutting Frame.

The elliptical movement of the tool is produced as in the geometric pen, and in lbbetson's geometric chuck, by the combination of two circular movements in opposite directions, the one of which travels at double the angular velocity of the other. In the Elliptical Cutting Frame this is effected by the train of wheels seen in the front of the instrument, which are so arranged that the eccentric frame carrying the tool A makes two revolutions to the right, while the radial flange B makes one revolution to the left; and the proportions of the ellipse described by the tool depend upon the relative degrees of eccentricity given to A and B. Thus, when A and B are both placed central, the tool has no eccentricity, and merely produces a dot. When eccentricity is given to A alone, the tool describes a circle, the radius of which will depend upon the movement given to the screw of the eccentric frame, under the guidance of the micrometer head C, which has ten divisions. Supposing the eccentricity to be equal to 4 turns of the screw, or A 0 divisions of the micrometer head, and that it is desired to convert the circle into a straight line, the flange B is also moved 40 divisions, by means of the adjusting screw D, upon which a winch handle is temporarily fitted.

Any series of ellipses between the straight line and the circle may be described by reducing the eccentricity of the radial flange B. Thus, if it be shifted 5 divisions between each figure, a series of 7 ellipses will be produced, gradually advancing from the right line to the circle. Any other number of divisions may be adopted in the same manner; the instrument being so adjusted that equal numbers of divisions on B and C always produce the straight line. Series of concentric ellipses are produced by adjusting both A and B; thus, in pattern 1, A was shifted 4 divisions, and B two divisions between every cut.

The radial action of the flange B, however, has the effect of placing the ellipses oblique to each other, instead of parallel, and this requires some compensation to be introduced. Captain Ash compensated the obliquity by shifting the division plate of the lathe a proportionate quantity. Subsequently, the spindle was extended through the stem of the instrument, and a graduated disk fixed on the end of the spindle was employed for the compensation, but which is more conveniently and accurately effected by means of the worm wheel and tangent screw movement, suggested by H. Perigal, Esq., F.R.A.S. The tangent screw E is moved by a winch handle, and has a micrometer so arranged, that the movement indicated by one division exactly compensates the obliquity produced by moving the flange B one division; and therefore, to ensure the parallelism of the ellipses, it is only necessary to employ the same number of divisions on B and E. The tangent screw movement may also be employed to give any angular position to the ellipses that may be required. Thus, the worm wheel having 150 teeth, 37 1/2 turns of the tangent screw will place any of the figures at right angles to their former positions.