When the same splint plane was used for the stronger and less flexible matches nearly one-tenth of an inch square now used, the splints were found to be broken or disrupted in their fibres, by the comparatively abrupt angle at which they were removed from the block of wood, notwithstanding that the plane had a very thin iron sole and a cutter of very low pitch. This defective action of the hand plane led to the invention of Mr. Mayer's Patent Splint Cutting Machine, used exclusively at the celebrated works of the Messrs. Esdailes and Margrave of London.
The splint-cutting machine has a metal slide, which travels parallel with the ground, but in a vertical plane, by means of a crank and connecting rod that give it 60 strokes in a minute. The slide carries first a series of 30 lancet-like knives, half sloped on the upper surface, the other half on the lower, these penetrate the wood about one-tenth of an inch, and are immediately followed by the cutter or plane iron, the broad flat side of which rests directly against the wood to be cut, (no sole being used,) the edge of this knife is very much inclined, namely, to 70 degrees, and is ground with a very long bevil, 2 inches wide, giving to the edge the acute angle of 12 degrees, and which, combined with the great obliquity of the knife causes the splints to be only bent from the wood at the insignificant angle of about 4 degrees, so as to be entirely removed by cutting, and not by splitting or rending.
The wood used for making the splints consists of whole deals 10 inches wide, 3 inches thick, cross cut into blocks 5 inches long. Three of these blocks are placed together, constituting a length of 15 inches, sufficient for six splints or matches: and as there are thirty lancet knives, every traverse of the machine produces 180 splints; this at 60 strokes a minute makes 648,000 an hour, or 6,480,000 in a day of ten hours. There are two such machines constantly at work, and these, notwithstanding the average production of each is upwards of three millions of splint a day, furnish another proof that in some processes, machinery cannot overpower hand labour; as the larger proportion of the splints used in this country are nevertheless obtained from the hand cutters and foreign importations. The hand-cut splints although cheaper are inferior to those cut by the machines in question.
When the tools 481 or 432 p. 533 are used in both directions, that is if some-times moved towards the right hand, at other times to the left, it is then necessary the chamfer or upper face of the point should be ground square across to serve for either direction of motion. But when the tool is used exclusively from the right hand towards the left, the chamfer should be so ground that the left side is the higher, as this from being then the entering angle of the tool, works much more freely from being sloped some 30 degrees from the horizontal, as already explained.
On the Tory same principle an efficient side-cutting tool for iron to be used in the slide rest, is derived from the triangular tool, page 521, and represented in three views in the annexed figure 982. A bar of steel is drawn down at the end, to about half its thickness, the width, or rather the vertical height remaining unaltered, this narrow part is chamfered on its outer face, so as to be a little inclined from the perpendicular, and is then ground on its upper surface to make a ridge parallel with the side of the tool The ridge which is sloped about 80° from the horizontal, is sometimes on the right, sometimes on the left, as the tools are made in pairs; and as they will readily remove a shaving an inch or more wide, a cylinder of six inches diameter may be reduced to four inches or less at one cut, in a lathe having proportionate power.
Note AR, page 538. - To follow the paragraph ending, "for general purposes." (On lubricating metal turning tools with water.)
When water is used for lubricating the took in turning iron with band tools, the most simple plan is to dip the tool occasionally into a small vessel containing the fluid. A more effectual way employed in turning by hand or with the slide rest, is to make a small mop, of a bit of rag surrounded by a loop of wire, the cuds of which are twisted together to form a handle, as in a bottle brush, with which the work is occasionally moistened.
In turning with the slide-rest or self-acting lathe, practical men often fix a drip can to the slide-rest, that the water may fall on the work close by the tool; or in the best mode a flexible hose is used that leads from a cistern above, the discharge of water being regulated by a small tap. These two modes require that metal pans should be placed beneath the work to catch the water that runs away, and also that some vigilance should be exerted to keep the lathes from becoming rusty.
Notes AS, AT, AU and AV. - To follow the last line of page 538. (On the Principles of Tools for Turning and Planing Metals.)
The formation of the tools used for turning and planing the metals is a subject of very great importance to the practical engineer, as it is indeed only when the mathematical principles upon which such tools act, are closely followed by the workman, that they produce their best effects. With a full conviction of the advantages which result when theory and practice are thus associated, the author has to congratulate himself on being able to present to his readers, two original papers, respectively written on the subject of the principles of tools for turning and planing metals, by Charles Babbage, Esq., F.R.S., etc, and Professor Willis, A.M., F.R.S., etc, both distinguished by their high mathematical attainments, and their intimate practical experience in the use of tools.