364 FILE 



are sometimes a little coarser than the rough ; they are known by the name of 

 rubbers. 



Files are also distinguished from their shape, as flat, half-round, three-square, four- 

 square, and round. The first aro sometimes of uniform breadth and thickness 

 throughout, and sometimes tapering. The cross section is a parallelogram. The 

 half-round is generally tapering, one side being flat, and the other rounded. The 

 cross section is a segment of a circle varying a little for different purposes, but seldom 

 equal to a semicircle. The throe-square generally consists of three equal sides, being 

 equilateral prisms, mostly tapering; those which are not tapering are used for 

 sharpening the teeth of saws. The four-square has four equal sides, the section 

 being a square. These files aro generally thickest in the middle, as is the case with 

 tho^ smith's rubber. In the round file the section is a circle, and the file generally 

 conical. 



The heavier and coarser kinds of files are made from the inferior marks of blistered 

 steel. Those made from the Kussian iron, known by the name of old sable, called 

 from its mark CCND, aro excellent. The steel made from the best Swedish iron, 

 called Hoop L or Dannemora, makes the finest Lancashire files for watch and clock 

 makers. 



The steel intended for files is more highly converted than for other purposes, to give 

 them proper hardness. It should, however, be recollected, that if the hardness be not 

 accompanied with a certain degree of tenacity, the teeth of the file break, and do but 

 little service. 



Small files are usually made of cast steel, which would be used for all other kinds, 

 if it were not for its high price. It is much harder than the blistered steel, and from 

 having been in the fluid state, is entirely free from those seams and loose parts 

 which are common to blistered steel. 



The smith's rubbers are generally forged in the common smith's forge, from the 

 converted bars, which are, for convenience, made square in the iron before they 

 come into this country. The files of 'lesser size are made from bars or rods, drawn 

 down from the blistered bars, and the cast ingots, and known by the name of tilted 

 steel. 



The file-maker's forge consists of large bellows, with coke as fuel. The anvil-block, 

 particularly at Sheffield, is one large mass of millstone grit. The anvil is of con- 

 siderable size, set into and wedged fast into the stone ; and has a projection at one 

 end, with a hole to contain a sharp-edged tool for cutting the files from the rods. It 

 also contains a deep groove for containing dies or bosses, for giving particular forms 

 to the files. 



The flat and square files are formed entirely by the hammer. One man holds the 

 hot bar, and strikes with a small hammer. Another stands before the .anvil with a 

 two-handed hammer. The latter is generally very heavy, with a broad face for the 

 large files. They both strike with such truth as to make the surface smooth ami 

 flat, without what is called hand-hammering. This arises from their groat oxpcrienee 

 in the same kind of work. The expedition arising from the same cause is not less 

 remarkable. 



The half-round files aro made in a boss fastened into the groove above mentioned. 

 The steel, being drawn out, is laid upon the rounded recess, and hammered till it fills 

 the die. 



The three-sided files are formed similarly in a boss, the recess of which consists of 

 two sides, with the angle downwards. The steel is first drawn out square, and then 

 placed in a boss with an angle downwards, so that the hammer forms one side, and 

 the boss two. The round files are formed by a swage similar to those used by 

 common smiths, but a little conical. 



The file-cutter requires an anvil of a size greater or less, proportioned to the size of 

 his files, with a face as even and flat as possible. The hammers weigh from one to 

 five or six pounds. The chisels aro a little broader than the file, sharpened to ;m 

 angle of about 20 degrees. The length is just sufficient for them to be held fast bi- 

 tween the finger and thumb, and so strong as not to bond with the strokes of tho 

 hammer, the intensity of which may be best conceived by the depth of the impression. 

 The anvil is placed in tho face of a strong wooden post, to which a wooden scat is at- 

 tached, at a small distance below tho level of tho anvil's face. Tho file is first l.ii.I 

 upon tho bare anvil, one end projecting over tho front, and tho other o\\-r th- 1-ark 

 edge of tho same. A leather strap now goes over each end of tho file, and pass, s down 

 upon each side of the block to tho workman's feet, which, being put into tho str;ij> <.n 

 each side, like a stirrup, holds the file firmly upon the anvil as it is cut. "While tho 

 point of the file is cutting, tho strap passes over one part of the file only, tho point 

 resting upon tho anvil, and the tang upon a prop on tho other side of the strap. "\Vln-n 

 one side of the file is single cut, a fine file is run slightly over tho tooth, to take away 



