61G 



BLOCK MACHINERY 



Method of 

 -using the 



k Ma- the points of two centres. Screws are seen at / on 

 chiti cr;-. t ] iese con trcs. The frame inclines when the handle 

 V ~~~ J L is depressed. At M is a lever, with a weight at 

 the. end of it, counterbalancing the weight of the 

 blocks and plate D, all which are above the centre 

 on which they mo\e. The frame F is also provided 

 with a counterpoise to balance the cutters, &c. The 

 cutters E, E are circular wheels of brass, with round 

 edges. Each has two notches in its circumference, at 

 opposite sides ; and in these notches chisels are fixed 

 by screws, to project beyond the rim of the wheel, 

 in the manner of a plane iron before its face. 



This machine is used as follows : In order to fix the 

 block, it is pressed between the two pins, (only one of 

 scoring en- w },i c ] 1 atflf can be seen in view), and the clamp d screw- 

 ' edupagainst it,soasjusttoholdtheblock,butnomore. 



The clamp has two claws, as is seen in the Figure, 

 each furnished with a ring, entering the double 

 prints before mentioned, in the end of the block. 

 These rings are partly cut away, leaving only such a 

 segment. of each as will just retain the block, and the 

 metal between them is taken out to admit the cutter 

 to operate between them, or nearly so. In putting 

 the blocks into this machine, the workman applies the 

 double prints to the ends of the claws of the clamps, 

 but takes care that the blocks are higher up between 

 the pins a than they should be ; he then takes the 

 handle f, and by it presses the cutters EE, (which we 

 suppose are standing still,) down upon the blocks, 

 depressing them between their pins at the same time, 

 till the descent of the cutters is stopped by the piece 

 h resting on the shape g. He now turns the screws 

 bb, to fix the blocks tight. The cutters being put 

 in motion, cut the scores, which will be plainly seen 

 by the mode of adjustment just described, to be of 

 no depth at the pin hole ; but by depressing the 

 handle L, so as to incline the blocks, and keeping 

 the cutters down upon their shape g by the handle f, 

 they will cut any depth towards the ends of the 

 blocks, which the shape g admits. 



By this means, one quarter of the score is formed; 

 the other is done by turning both blocks together 

 half round, in this manner : The centres / are not 

 fitted into the plate D itself, but into a frame seen at 

 R, beneath the plate, which is connected with it 

 by a centre pin, exactly midway between the two 

 blocks A, B. A spring catch, the end of which is 

 seen at r, confines them together ; when this catch is 

 pressed back, the plate D can be turned about upon 

 its centre pin, so as to change the blocks, end for 

 end, and bring the unscored quarters (i. e. over the 

 clamps) beneath the cutters; the workman taking the 

 handles/ and L, one in each end, and pressing them 

 down, cuts out the second quarter. This might 

 have been effected by simply lifting up the handle 

 L ; but in that case the cutter would have struck 

 against the grain uf the wood, so as to cut rather 

 roughly; but by this ingenious device, of reversing 

 the blocks, it always cuts clean and smooth, in 

 the direction of the grain. The third and fourth 

 quarters of the score are cut, by turning the other 

 sides of the blocks upwards, and repeating the above 

 operation. The shape g can be removed and another 

 put in its place, for diiFerer.t sizes and curves of 



7 



blocks ; but the same pins a, and holding clamps d, Block M*. 

 will suit many different sizes. chinery. 



By these machines the shells of the blocks are com- 

 pletely formed, and they are next polished and finish- 

 ed by hand labour ; but as this is performed by tools 

 and methods which are well known, it is needless to 

 enterinto any explanation: the finishing required being 

 only a smoothing of the surfaces. The machines cut 

 so perfectly true, as to require no wood to be removed 

 in the finishing ; but as they cut without regard to the 

 irregularity of the grain, knots, &c. it happens that 

 many parts are not so smooth as might be wished, 

 and for this purpose manual labour alone can be em- 

 ployed. 



The lignum vita; for the sheaves of the blocks, is 

 cut across the grain of the wood by two cross cutting 

 saws, a circular and straight saw, as before mentioned. 

 These machines do not essentially differ in their prin- 

 ciple from the great cross cutting saws we have de- 

 scribed, except that the wood revolves while it is cut- 

 ting, so that a small saw will reach the centre of u 

 large tree, and at the same time cut it truly flat. As 

 the limits prescribed our Plates will not admit of giving 

 drawings of these machines, and as the idea which 

 could be derived from a verbal description would not 

 be materially different from the cross cutting saws be- 

 fore mentioned, we shall defer any farther account of 

 them till a future opportunity. These machines cut 

 off their plates for the end of the tree, which are ex- 

 actly the thickness for the intended sheave. These 

 pieces are of an irregular figure, and must be rounded 

 and centered in the crown saw. 



The crown saw is represented in Plate LX. Fig. 2. Crown 

 where A is a pulley revolving by means of an endless 8aw " 

 strap. It has the crown or trepan saw a fixed to it, by Plate 

 a screw cut within the piece, upon which the saw is l-.X. 

 fixed, and which gives the ring or hoop of the saw S" 

 sufficient stability to perform its office. Both the pul- 

 ley and saw revolve together upon' a truly cylindrical 

 tubei, which is stationary, being attached by a Haunch 

 c to a fixed puppet B, and on this tube as an axis, the 

 saw and pulley turn, and may be slid endwise by a 

 collar fitted round the centre piece of the pulley, and 

 having two iron rods (only one of which can be seen at 

 d in the figure, ) passing through holes made through 

 the flaunch and puppet B. When the saw is drawn 

 back upon its central tube, the end of the latter pro- 

 jects beyond the teeth of the saw. It is by means of 

 this fixed ring or tube within the saw, that the piece 

 of wood e is supported during the operation of saw- 

 ing, being pressed forcibly against it by a screw D, 

 acting through a puppet fixed to the frame of the 

 machine. At the end of this screw, is a cup or bason 

 which applies itself to the piece of wood, so as to 

 form a kind of vice, one side being the end of the 

 fixed tube, the other the cup at the end of the screw 

 D. Within the tube b, is a collar for supporting a 

 central axis, which isperfectly cylindrical. The other 

 end of this axis (seen at f,) turns in a collar of the 

 fixed puppet E. The central axis has a pulley F, fixed 

 on it, and giving it motion by a strap similar to the 

 other. Close to the latter pulley a collar g is fitted on 

 the centre piece of the pulley, so as to slip round 

 freely, but at the same time confined to move end- 



*t*r. 





