192 



KNOAVLEDGE ♦ 



[March 6, 1885. 



"Wolverhxmpton, \i ere amongst the finest machines shown, 

 both as regards design and workmanship. 



In my next I shall refer at some length to the 

 Cunard front-tteerer, which I regard as a tricycle of the 

 most advanced type. 



THE YOUNG ELECTRICIAN. 



By W. Slingo. 



(Conllntictl from p. 154.) 



"WJ E cow come to the second portion of the apparatus 

 Vt necessary to perform the operations of diilliog, 

 viz., the drill-stock. 



Ex. XXXII. Tbe American drill-stock is one which is 

 very frequently used. To the handle, H (Fig. 11), is fixed 



A 



a frame, upon the side of which the driving-wheel A B is 

 attached. This wheel gears into one or two (in the form 

 illustrated, two) small pinions rigidly fastened to the drill- 

 spindle, at the free end of which is the drill chuck. This 

 chuck is generally adjustable, that is to say it is capable 

 of taking drills made from wire of various diameters. A 

 portion of a drill i.s shown in position at D. Obviously 

 the rotation of the wheel A B by means of the handle F 

 causes the pinion, and with it the drill, to revolve more or 

 less rapidly in one constant direction. It is too apparent 

 that it would be out of all reason for the young worker 

 to attempt the manufacture of a tool of this description. 

 It is, however, very handy, and not expensive. The form 

 illustrated, which is made of malleable iron with tteel 

 spindle and chuck, may be obtained from Messrs. Churchill 

 and Co , Cross-street, Finsbury. 



E.v. XXXIII. There is another and even a cheaper form 

 of drill-stock, viz., the Archimedian, in which the drill is 

 made to rotate by moving a nut up and down a coarse 

 .spiral thread on tlie drill spindle. It is not to be recom- 

 mended, however, to amateurs, as considerable skill is 

 necessary to keep it steady. A want of steadiness natu- 

 rally involves bending and frequently breaking the drills — 

 rather an annoying experience. 



B[3L£: 



"^v 



Fig. 12. 



E.x. XXXIV. Let us now turn to a form of stock which, 

 while it is very largely employed by practical men in their 

 everyday work, can be made and used by young workers 

 without any gre^t tax either on their ingenuity or their skill. 

 It consists of three p:irts, the drill stock (Fig. 12), the 

 bow (Fig. 1.3), and the breastplate (Fig. 14) To use it, 

 the drill is placed in the stock, the pointed end of which, 

 after being slightly oiled, is fitted into the central hole in 

 the breast-plate. The gut of the bow is pissed once round 



the reel. The bow, on being worked to and fro, will cause 

 the drill to revolve and do its work. 



A rf 



To make the drill stock, procure a piece of bright stee? 

 wire, about a quarter of an inch in diameter, and il 

 inches long. At one end, A, make a rather long conical 

 point. When made, the point must be hardened by the 

 method described in Ex. XXX. A hole is now to be 

 bored in the other end (B) of the wire. As, however, we 

 are assuming that our young worker is making his first 

 piece of apparatus for rotating a drill, he is at this parti- 

 cular point unfortunately nonplussed. But the difficulty 

 is not by any means insuperable. Let him take his piece 

 of wire to a metal-worker and have, at a very trifling 

 expense, the necessary hole bored. The diameter of the 

 hole must be the same as that of the wire from which 



Fig. 14. 



the drills are made, and the depth of the hole should be 

 about three eighths of an inch. The hole being bored, 

 a slot, C, three-sixteenths of an inch wide, must be cut, 

 with the edge of a fl^t bastard file, in the wire near the 

 end, B. The centre of this slot must coincide with the 

 end or bottom of the longitudinal hole just bored, while 

 tbe bottom of the slot should be a little below and 

 parallel with the axis of the wire. The object of the 

 slot is to prevent the drill-spindle slipping round the 

 drill (which would, in that case, remain stationary, 

 doing no work). A reference to Fig. 10 (page 153) 

 will help to explain matters. It will be seen that tbe 

 unhardened end of each drill has a portion of the 

 steel cut away, so that a flat surface is produced at about 

 the axis of the wire. The consequence of this is that 

 when the drill is placed in the hole in the drill-stock, the 

 reduced end passes to the remote end of the slot, while the 

 edges of the flat surface of the drill, coming in contact 

 with the bottom of the slot, compel the drill to rotate 

 with the stock. 



Now for the rotation of the drill-stock. Procure a 

 wooden reel, to shape shown (C D) in the figure. The 

 diameter of the reel should be seven-eighths of an inch at 

 the ends and five eighths at the bottom of the curved 

 groove. The length of the reel should be about three- 

 quarters of an inch, a hole being bored through the centre 

 a trifle smaller than the size of the wire. To fix the reel, 

 drive it gently on to the spindle to about an inch from the 

 end ; but this particular distance is not important. The fact 



