302 



Popular Science Monthly 



same 



Drilling Square Holes 



THE drawings relate to work that is 

 drilled in the lathe. The 

 piece is shown in Figs, i, 2 

 and 3, Figs, i and 2 showing 

 round and square holes. They 

 are the formers and are used 

 for drilling square holes in 

 round stock, such as would 

 be used for socket-wrenches, 

 etc. Let us say we need an 

 inch-square hole. The 

 stock is put in the lathe 

 chuck and drilled with a one-inch round 

 drill. Then the former (Figs, i, 2, 3) 

 is slipped over the stock and fastened 

 with the set screw, C. This brings the 

 one-inch square, B, against the one-inch 

 round drilled hole. The tool. Fig. 5, is 

 then inserted in the back-center of the 

 lathe and fed to the round hole, tlie 

 three-sided drill, D, cutting the hole 

 one inch square. 



This is caused by the square in the 

 former going around the drill, and the 

 drill having a pla^- in all directions. 



The play of the drill is pro\-ided for 

 by the simple means of something like a 

 modified universal joint, E and F, Figs. 

 4 and 5, the pin E fitting loosely in part 

 F. Being rounded, the part F has a 

 movement that works two ways and 

 the pin E makes the other two move- 

 ments. Hence we see that this provides 

 for a limited circular movement. 



If the work (flat stock or otherwise) is 



Fig. 6. Former, to be 

 held in tool post of 

 lathe when drill is 

 running and work is 

 on back center 



needed to be drilled, the tool (Fig. 4) is 

 inserted in the lathe head, and the tool 

 (Fig. 5) is used in the tool post, the 

 former part / being brought 

 up to the work, which is 

 secured by an>- ordinary 

 means to the back center. The 

 position of the drill in cut- 

 ting square hole is shown in 

 Figs. 7 and 8. It must be 

 understood that the former 

 must be as close to the work 

 as possible. The former 

 should be hardened and the drill edges 

 slightly rounded. 



The cutting end of the drill should be 

 slightly rounded, similar to a reamer 



Fig. 7 Fig. 8 



Showing two positions of three-sided drill 



about to cut the round hole square 



edge. Of course the drill has not much 

 work to do — simply taking out the 

 round corners. It can be used in the drill 

 press, the work and former being strapped 

 to the table. — Edgar Hoi.dcroft. 



A Remedy for Jarring Bottles 



^^x TN order to keep bottles from jarring 



I 



Fig 2 Fig.3 



Formers for round stock that is held in 

 lathe chuck 



from being knocked oft" a shelf which 

 may be remote from the lathe, a tin 

 can is nailed down to the shelf and 

 about iK "IS. of shavings and sawdust 

 placed in it to keep the bottle from being 

 broken when dropped into it. 



Fig. 5. Same as Fig. 4, but assembled 



The bottle can not slide or jar off 



