WORKSHOP FILES

Sun (Auckland), Volume I, Issue 124, 16 August 1927, Page 6

WORKSHOP FILES

LENGTHENING THEIR LIVES. SOME PRACTICAL METHODS. The lives of steel workshop files are often short owing to their becoming clogged with metal which Jias been removed from the work upon which they have been used. The following are some of the methods which may be adopted with them in order to lengthen their lives: — If the teeth are choked up with greasy dirt, solder, lead, aluminium, or one of its alloys, the files should be boiled in a strong solution of caustic soda, which will dissolve or remove impurities After this treatment rinse well in water. Next scrape the file well with a steel wire brush or file cord, and finally wash in hot water and dry off quickly. When brass, copper, or zinc is the metal to be removed, the files, after having been treated as in the foregoing paragraph, should be immersed in a solution composed of two volumes of nitric acid, one volume of hydrochloric acid (also known as spirits of salts, or muratic acid), and 12 volumes of water the quantity of solution made up of course depending upon the number and size of the fifes to be treated. After treatment in this solution, in order to prevent their rusting, the files should be immersed in caustic soda solution, well rinsed with water, and then dried in warm sawdust. If the files have been used on iron or steel, after having been treated with the boiling soda solution as above and well washed, they should he immersed in a solution of copper sulphate, rinsed in water, then treated with acid solution mentioned in the preceding paragraph, and finally made rust-proof with the caustic soda and sawdust treatment. To resharpen files with acid solution they should first be cleaned by being boiled in caustic soda solution for a quarter of an hour. It is absolutely essential that the files should be thoroughly cleaned, as the acid cannot reach the steel through grease or oil. Ten to 15 per cent, of caustic soda will be found to give good results. After the files have been cleaned in this manner they should be placed in an acid bath, composed of equal volumes of nitric acid. hydrochloric acid, and water. The files should be dipped in this solution one at a time, and immediately after being taken out placed in a large volume of water and then washed in plenty of running water. To get rid of all the acid immerse the files in a solution of common washing soda, again rinse, and dry thoroughly. Before packing away rub a little oil or vaseline on the files, as an extra precaution against rust. Care should be taken in using the acid, which on no account should he allowed to get on the hands. In workshops where a great number of files are used a considerable saving can be effected by rejuvenating old files as shove. Your half of the road is not the middle half.