THE TECHNOLOGIST. [Sept. 1, 1864. 



t>2 ON THE MACHINERY FOR 



keep the main line of shafting continuous, for driving a series of tables 

 in one room. Over the top of the table a strong timber bar is fixed, 

 about 10 in. from its surface ; and on the two opposite sides of this bar 

 are bolted two notched plates of cast-iron, one on each side of the centre 

 of the table. The notches are for receiving the centre studs of the runner 

 frames, which are very similar to those used on the old class of ma- 

 chinery ; and the runners can thus readily be moved nearer to or fur- 

 ther from the centre of the table, as circumstances require, by shifting 

 the stud into a different notch. The only motion which these runner 

 frames have is round their own centres, and this is given to them by 

 the excess of friction on the side furthest from the centre of the table 

 over that on the side nearest to the centre, this excess being caused by 

 the greater velocity of the portion of the table further from the centre. 

 It is evident that the amount of grinding action is considerably greater 

 on this machine than upon the old one, both from the increased velocity 

 of the runner frames themselves, and also from the double amount of 

 movement obtained by the revolution of the table and the runner frames. 

 The idea of driving the runner frames themselves, as well as the table, 

 was conceived at an early stage of the experiments ; . but on being put 

 to the test, it was found that the unaided movement of the runner 

 frames adapted itself to the work to be performed far better than any 

 compulsory motion could do. It has also the advantage of leaving the 

 surface free and unencumbered with any machinery, and consequently 

 facilitates the operation of laying and removing the plates of glass ; the 

 whole of the driving machinery is also covered over, and thus protected 

 from the injurious effects of the sand and water thrown off from the 

 edge of the table in working. 



This machine has been found to answer equally well for smoothing 

 as for grinding ; and this is perhaps its most successful feature in a 

 commercial and economical point of view. Both these processes are now 

 completed on it at the Ravenhead Glass "Works, the finishing portion of 

 the smoothing operation alone being effected by manual labour for the 

 reasons before stated. The plates of glass being generally oblong in 

 form, it was found that the machine in its original shape, having a cir- 

 cular table for carrying the glass, entailed considerable waste in filling 

 up the area of each table for grinding ; and it wa3 then determined to 

 alter the shape to that of an unequal-sized octagon, or square with the 

 corners taken off. No difficulty has been experienced in the process of 

 grinding from this alteration in form, whilst the amount of waste in 

 making up the tables has been considerably reduced, and greater facili- 

 ties are obtained for grinding large plates. The amount of wear and tear 

 on this machine has been found to be very small in comparison with 

 the old machines, owing to the small number of working parts, the large 

 extent of bearing surface, the smoothness of the motion, and the com- 

 plete balancing of the table. The quantity of glas3 finished upon one of 

 these machines per week is 1,200 to 1,500 square feet, which is about 



