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On cutting half-round, and other curve-faced files
On Cultin~ Curve-faced Files.
211
process, at an expense of only two or three cwt. of slack to each t o n of oil. It appears to me that the coloring matter is discharged by the absorptiotl of oxygen fro'm the atmosphere, as oil at a high temperature is known to have a strong affinity for oxygen at a high temperature, and hence agitation is essential, so as continually to present a new surface. I inadvertently made it known, and although it is of great importance to the trade, 1 shall derive no benefit from it. Ibid.
On Cutting Hal.f-round, and other Curve-faced Files. By the late Sir Jor I~ Ro~IsoN, K.H., F.R.S.E., F.R.S.S.A.* It is well known to workmen, that ahhough it be an easy matter to getjqat-faced files of almost any required degree of smoothness and regularity of surface, a half-round file having an approach to such smoothness, or regularity, is altogether unattainable at any cost. A method having occurred to me of striking half-round, or even round, files with the same smoothness, and with nearly the same accuracy of figure, as the fiat files, I beg leave to submit the process to the Society, that it may, through these means, become known to those to whom it may be of use.. To form a half-round file, either convex, or concave, I propose that blanks should be prepared as if for thin equalit~g-files, (i.e. of uniform thickness and breadth throughout,) and that they should be struck on one face, or both faces, of the degree of fineness required. This having been done, I propose that, by means of a screw-press, and swages of copper, or crther soft metal, they should have the required degree of curvature impressed on them before being hardened, and that, in this manner, files with curved faces, but with the teeth of equable depth all across them, should be obtained. In a similar manner 1 propose to form three-quarters round, or even cylindric, smooth files, by cutting fiat blanks on one face, and then bending them on steel mandrils into a tubular form previous to hardening them. On communicating this plan to the eminent manufacturer, Mr. Stubbs, of Warrington, I learned from him that something of this kind had been attempted by his house, but abandoned on account of the difficulty experienced in getting the files into the curved shape after they were struck. Mr. Stubbs, at the same time, sent me a file so made, thirty years before. This file at once explained how the difficulty had arisen, as, instead of the blank haying been made of uniform thickness and breadth, it has been fashioned like an ordinary crossing file, and, therefore, not susceptible of being squeezed into the regular curved shape by simple pressure. If Mr. Stubbs had thought of making the flat blank, he would, no doubt, have succeeded better; * Read before the Royal Scottish Society of Arts, 12th December, 1842.
212
Mechanics, Physics, and Chemistrg.
and the formation of tubular files, which he aeknow, ledges never o¢~curred to him, must have followed the other at a short interval.
Extract of a letter from Messrs. Johnson, Cammell 8/Co., Shea~eld, to the late Sir John Robison, K. H., F.R.S.E., Nov. 7, 1843. W e now have the pleasure to hand you, as requested, an extract fi'om our letter of Feb. 13th last, to the late Sir John Robison, explaining the mode we then adopted in the manufacture of the half-round files from sleel of parallel thickness, as suggested by him, viz., by means of a screw-press, and swages of copper, and which we see is d~e plan named in the paper communicated to the Society. From the specimens sent you last week, you will perceive we have deviated fi'om the plan first suggested, " o f cutting them from blanks of steel prepared as for a thin equaling-file." We, however, did not give up this plan until, from practical experience, we found its working very uncertain and irregular, for the file being of uniform thickness, the edges presented an equal, or greater, degree of resistance to pressure, than the centre ; and the top swage, or boss, coming in contact with the centre of the file previous to any other part, caused it to bend more freely than the edges, producing various degrees of curvature in the same file. Again, if our top boss was so shaped as to create an earlier and fi'eer pressure on the edges, lo ensure a more uniform curve, we then endangered the sharpness of the teeth oa those parts of each side of the file, convex and concave, first receiving such undue pressure. These objections and difficulties are all overcome, or lessened, by our present mode of cutting and turning the files from steel with slightly tapered edges on one side, thus, The fiat surface is cut with a continuoustooth, and canbe turned either convex or concave, and the tapered surface can either be cut in ridges, or left safe, or uncut, which, from the following extract, yon will perceive, was Sir John's first idea. h l Sir John Robison's first communication, N o v e m b e r 10, 1842, after recounting the diffmulty of obtaining a smooth half-round file, or one of equal continuous tooth, he says : ~ , I propose to overcome this difficulty, and to cut half-round files as truly smooth as fiat ones are now struck, by making the blanks of rolled steel-plate ; by striking them in the fiat state, and by afterwards giving them the degree of curvature required, by means of a screwpress, and tin, or copper, swages ; or else by passing them between grooved and furrowed rolls (of soft metal for the struck side)," evidently implying that one side would be unstruck, or uncut. In fact, for some time, at first we only attempted to cut one side of the file, and frequently now we are requested to leave sometimes the concave, and others the convex surface, blank, or uncut. Edin. New Philos. Journ.
ElMngton's Process o f Electro-Plating and Gilding. PELLATT.
B y Mr.
It is immaterial what metal is used for articles to be plated b y this
211
process, at an expense of only two or three cwt. of slack to each t o n of oil. It appears to me that the coloring matter is discharged by the absorptiotl of oxygen fro'm the atmosphere, as oil at a high temperature is known to have a strong affinity for oxygen at a high temperature, and hence agitation is essential, so as continually to present a new surface. I inadvertently made it known, and although it is of great importance to the trade, 1 shall derive no benefit from it. Ibid.
On Cutting Hal.f-round, and other Curve-faced Files. By the late Sir Jor I~ Ro~IsoN, K.H., F.R.S.E., F.R.S.S.A.* It is well known to workmen, that ahhough it be an easy matter to getjqat-faced files of almost any required degree of smoothness and regularity of surface, a half-round file having an approach to such smoothness, or regularity, is altogether unattainable at any cost. A method having occurred to me of striking half-round, or even round, files with the same smoothness, and with nearly the same accuracy of figure, as the fiat files, I beg leave to submit the process to the Society, that it may, through these means, become known to those to whom it may be of use.. To form a half-round file, either convex, or concave, I propose that blanks should be prepared as if for thin equalit~g-files, (i.e. of uniform thickness and breadth throughout,) and that they should be struck on one face, or both faces, of the degree of fineness required. This having been done, I propose that, by means of a screw-press, and swages of copper, or crther soft metal, they should have the required degree of curvature impressed on them before being hardened, and that, in this manner, files with curved faces, but with the teeth of equable depth all across them, should be obtained. In a similar manner 1 propose to form three-quarters round, or even cylindric, smooth files, by cutting fiat blanks on one face, and then bending them on steel mandrils into a tubular form previous to hardening them. On communicating this plan to the eminent manufacturer, Mr. Stubbs, of Warrington, I learned from him that something of this kind had been attempted by his house, but abandoned on account of the difficulty experienced in getting the files into the curved shape after they were struck. Mr. Stubbs, at the same time, sent me a file so made, thirty years before. This file at once explained how the difficulty had arisen, as, instead of the blank haying been made of uniform thickness and breadth, it has been fashioned like an ordinary crossing file, and, therefore, not susceptible of being squeezed into the regular curved shape by simple pressure. If Mr. Stubbs had thought of making the flat blank, he would, no doubt, have succeeded better; * Read before the Royal Scottish Society of Arts, 12th December, 1842.
212
Mechanics, Physics, and Chemistrg.
and the formation of tubular files, which he aeknow, ledges never o¢~curred to him, must have followed the other at a short interval.
Extract of a letter from Messrs. Johnson, Cammell 8/Co., Shea~eld, to the late Sir John Robison, K. H., F.R.S.E., Nov. 7, 1843. W e now have the pleasure to hand you, as requested, an extract fi'om our letter of Feb. 13th last, to the late Sir John Robison, explaining the mode we then adopted in the manufacture of the half-round files from sleel of parallel thickness, as suggested by him, viz., by means of a screw-press, and swages of copper, and which we see is d~e plan named in the paper communicated to the Society. From the specimens sent you last week, you will perceive we have deviated fi'om the plan first suggested, " o f cutting them from blanks of steel prepared as for a thin equaling-file." We, however, did not give up this plan until, from practical experience, we found its working very uncertain and irregular, for the file being of uniform thickness, the edges presented an equal, or greater, degree of resistance to pressure, than the centre ; and the top swage, or boss, coming in contact with the centre of the file previous to any other part, caused it to bend more freely than the edges, producing various degrees of curvature in the same file. Again, if our top boss was so shaped as to create an earlier and fi'eer pressure on the edges, lo ensure a more uniform curve, we then endangered the sharpness of the teeth oa those parts of each side of the file, convex and concave, first receiving such undue pressure. These objections and difficulties are all overcome, or lessened, by our present mode of cutting and turning the files from steel with slightly tapered edges on one side, thus, The fiat surface is cut with a continuoustooth, and canbe turned either convex or concave, and the tapered surface can either be cut in ridges, or left safe, or uncut, which, from the following extract, yon will perceive, was Sir John's first idea. h l Sir John Robison's first communication, N o v e m b e r 10, 1842, after recounting the diffmulty of obtaining a smooth half-round file, or one of equal continuous tooth, he says : ~ , I propose to overcome this difficulty, and to cut half-round files as truly smooth as fiat ones are now struck, by making the blanks of rolled steel-plate ; by striking them in the fiat state, and by afterwards giving them the degree of curvature required, by means of a screwpress, and tin, or copper, swages ; or else by passing them between grooved and furrowed rolls (of soft metal for the struck side)," evidently implying that one side would be unstruck, or uncut. In fact, for some time, at first we only attempted to cut one side of the file, and frequently now we are requested to leave sometimes the concave, and others the convex surface, blank, or uncut. Edin. New Philos. Journ.
ElMngton's Process o f Electro-Plating and Gilding. PELLATT.
B y Mr.
It is immaterial what metal is used for articles to be plated b y this