86 H. J. Grapon : 



4. — The Diamond. 



Under this heading it is proposed to allude briefly to the minor 

 but yet essential mechanical appliances for adjusting and con- 

 trolling the movements of the diamond during the act of ruling. 

 The principal features of the mechanism of the ruling carriage have 

 already been described and a short account given of the sequence in 

 ^vhich certain movements took place during the process of ruling. 

 (See page 49.) The follo^ving remarks so far as they relate to 

 the mechanism controlling the diamond, are sui^ijlementary to the 

 previous descrij^tion. 



Figs. 2 and -3, Plate XVI., are photographic views, back and 

 front respectively, of the ruling mechanism. Fig. -3 sho\vs in some 

 detail the following parts : — (1) The bar of hard steel of square 

 section supported in a steel frame with the aid of two hardened 

 conical screw pivots wliich permit of movement in arc of a few 

 degrees. Secured to this bar on its lower face there is a plate of 

 hard steel (37), i triangidar in shape, in the centre of which the 

 principal dash well (42) is placed, the diamond holder being 

 secured to its apex. This liolder is a small hollow cylinder (38) of 

 aluminium with solid end whose walls are partly slotted through to 

 hold the diamond clamp (39). The attachment of the solid end of 

 the cylinder to the triangular steel plate provides for rotational 

 adjustment. Three important movements of the diamond are pro- 

 vided for in this form of holder, viz. : (1) axial rotation of the rod 

 or pin 'jn which the diamond is mounted ; (2) movement of the clamp 

 block 39 in a vertical plane parallel with the direction of the lines 

 ruled; (3) movement in a direction or plane at a right angle to the 

 direction of the lines ruled. All these movements are important in 

 the preliminary setting up of a diamond. Two steel rods complete 

 the control outfit of the diamond ; one of these (4) is made to lift the 

 diamond from the plate after each line has been ruled, the other 

 supports the plunger of the dash well and is not shown by the 

 photograph. 



In Fig. 2, Plate XVI., we have a back view of the diamond 

 carriage and its fittings. Here may be seen an oblong block of 

 metal secured to the suspension bar and sei'ving as a counterpoise 

 to the trianu'ular frame and fittings of the diamond holder. This 

 block in addition to acting as a counterpoise is fitted with twO' 

 additional oil wells and dashers and also carries a projecting 



T The numbers refer to positions and parts indicated by corresponding- numbers on the plan of 

 tlie machine, Plate VI. 



