FILE 



305 



the roughness; when they arc to be double cut, .another set of teeth is cut, crossing 

 the former nearly at right angles. The file is now finished upon one side, and it is 

 evident that the cut side cannot be laid upon the bare anvil to cut the other. A flat 

 piece of an alloy of lead and tin is interposed between the toothed surface and the 

 anvil, while the other side is cut, which completely preserves the side already formed. 

 Similar pieces of lead and tin, with angular and rounded grooves, are used for cutting 

 triangular and half-round files. 



Hasps are cut precisely in the same way, by using a triangular punch, instead of a 

 flat chisel. The great art in cutting a rasp is to place every new tooth as much as 

 possible opposite to a vacancy. 



File-cutting machines have been from time to time invented. In 1778 M. de 

 Montigny read a memoir before the Committee of Commerce, in which he mentioned 

 the inventions for file-cutting in 1699 by Duverger, in 1725 by Fardouet, in 1740 

 by Thiout, in 1756 by Brachat and Gamain, and in 1778 ; since which, in 1800, Kaoul 

 invented a file-cutting machine; and in 1836 Ericsson introduced another. Sir John 

 Eobison, just before his death, invented a method for cutting curved files ; and in 

 1843, Messrs. Johnson, Cammell, and Co. received the medal of the Scottish Society 

 of Arts for perfecting Sir J. Kobison's scheme. The accompanying woodcuts, which 

 are representations of the file-cutting machine of Mr. W. Shilton of Birmingham, will 

 show the general principle upon which those machines are constructed. 



In order to render this inven- 

 tion better understood, two views 

 of the apparatus for producing the 

 crosscut or teeth of the files, are 

 given. 



Fig. 857 is an elevation of the 

 tipper part of the file-cutting ma- 

 chine, as seen on one side ; fig. 858 

 is a plan or horizontal view, as the 

 machine appears on the top. 



a, is the head of the tilt hammer 

 placed in the end of the lever b, 

 which is mounted on an axle c, 

 turning in proper bearings in the 

 frame work of the machine ; d, is 

 the tilt wheel mounted on another 

 axle s, also turning in bearings on 

 the frame work of the machine, 

 and having any required number of 

 projections or tappets upon it for 

 depressing the tail or shorter end 

 of the hammer or tilt lever b. 



The tilt wheel d, receives its 

 rotatory motion from the toothed 

 wheel /, mounted upon the same 

 axle, and it takes into gear with a 

 pinion g, upon the main shaft h, 

 which is actuated by a band passed 

 from any first mover to the rigger 

 on its end, or in any other con- 

 venient manner. The bed upon 

 which the blank piece of steel 

 bears is marked i. This bed is 

 firmly supported upon masonry 

 placed upon proper sleepers : j, is 

 one of the blank pieces of steel 

 under operation, and is shown 

 secured in the pair of jaws or 

 holdirig clamps k, mounted on centre pins in the slide /, fig. 858, which slide is 

 held down by a spring and slide beneath, and is moved backwards and forwards in 

 the machine upon the (v) edges m m, of the frame, by means of the rack n and its 

 pinion ; the latter being mounted upon the axle of the ratchet wheel p, and which 

 ratchet wheel is made to turn at intervals by means of the pall q, upon the end of the 

 lever r, fig. 858. This lever is depressed, after every cut has been effected upon the 

 blank by means of the teeth or tappets of the wheel s, coming in contact with the 

 inclined plane t, upon the lever r. The tappet wheel s, is mounted upon the end of 

 the axle e, of the tilt wheel, and consequently revolves with it, and by depressing the 



