PERFORATED PIPE 



248 



Applying the Idea of the Needle Bath 

 in Shell-Making 



THE steel utilized in the manufacture 

 of explosive shells must be carefully 

 tempered. If the steel is too brittle or too 

 ductile the destructiveness of the pro- 

 jectile is affected. Steel of the correct 

 temper, however, does 

 not lend itself readily to 

 heavy machine opera- 

 tions. For this reason, 

 steel shells, after the in- 

 sides have been removed 

 from the blanks and most 

 of the surplus material 

 cut from the outside, are 

 subjected to what is 

 called "heat treatment." 



The first step in heat 

 treatment is to bring the 

 shells to a comparatively WATE r 

 high temperature. Then 

 they are quenched, usu- 

 ally in oil, and once more 

 heated to bring the ma- 

 terial to the proper 

 condition. 



Although projectiles of . 

 all artillery ammunition 

 must be heat treated, the 

 cleverness of the French 

 and the ingenuity of the 

 Yankee has given manu- 

 facturers a substitute for 

 the oil bath which is an 

 interesting and unusual 

 adaptation of the familiar bath spray. 



The accompanying illustration could 

 with very little imagination be taken as a 

 model of the original needle bath. 



The shell bath is a cylindrical, double- 

 walled receptacle, not unlike one ashcan 

 placed within another. The space between 

 the concentric walls forms a reservoir 

 for a supply of water under pressure. 

 The inner wall is perforated, and there 

 is also a central perforated pipe passing 

 through the top of the needle-bath, 

 where it connects with a piece of ordinary 

 rubber hose. 



The shell to be cooled is placed in the 

 main chamber, the perforated pipe in- 

 serted in the nose of the shell and the 

 water sprayed on the inside and outside 

 of the heated case. 



The shell is taken for this bath from 

 a heating furnace where it has been kept 

 at a temperature of 1800 degrees Fahren- 



Popular Science Monthly 



5HELL 



heit for some thirty minutes, and it remains 

 in the bath until cooled thoroughly. 



Plunging the hot shell immediately into 

 a tank of cold water after taking it from 

 the furnace would be treatment too heroic 

 and would without doubt do a great deal 

 more harm than good ; but the gentle cool- 

 ing effect of the shower bath has 

 proved highly efficacious. 

 rubber hose a spray of cold water 

 seems to be as beneficial 

 to the temper of a shell 

 as it is conceded to be to 

 the temper of many a 

 fractious youngster. — 

 Reginald Trautschold, 

 M. E. 



The shell is placed in the main cham- 

 ber, the perforated pipe is inserted in 

 the nose of the shell and the water 

 is sprayed from inside and outside 



A Fortune from Old 

 Razor Blades 



A CALIFORNIA man 

 is making a little 

 fortune out of old safety- 

 razor blades. It seems 

 almost unbelievable but 

 it is not more strange 

 than the stories we hear 

 of fortunes made by rag- 

 pickers and dealers in old 

 tin cans. This man pat- 

 ented a suitable blade- 

 holder, which he sells 

 with supplies of old 

 blades to tailors, mil- 

 liners, show-card writers, 

 and photographers. 

 The holder is made from one piece of steel 

 bent in half with its two sides pressing close 

 together. One corner of the blade sticks 

 out from the holder. It will cut one 

 hundred ordinary sheets of paper or a 

 dozen pieces of cloth at 

 a single stroke. 



By means of a safety holder, the blades can 

 be used for cutting cloth, paper or cardboard 



