Democratic Sentinel, Volume 18, Number 11, Rensselaer, Jasper County, 30 March 1894 — Very Hard Steel. [ARTICLE]

Very Hard Steel.

The strong-rooms of a safety-de-posit company in London are constructed. throughqut of steel, the doors being faced further with a solid plate "half an inch thick, of patent compo safe steel. What kind of material this compo safe steel is may be gathered from a abscription of a re-

eent drilling test Tbe position of the holes was selected variously at random, and the steel used in the drills was ordinary high-class Sheffield steel. Subsequently Styrian and Mushet’s self-hardening steel were also tried. The drills were first tried with a temper corresponding to the usual “purple” for drilling iron. Later som«» were tried of a very stiff, strong form, completely hardened by being plunged in cold water and untempered in any way. This condition corresponds to that of the tool* found most suitable for cutting chilled iron. Other drills were tried, ranging through all degrees of hardness from that last described down to the softest “blue" temper for cutting Iron. The drills were lubricated by petroleum oil chiefly, but in the course of the trials other lubricants were used, such as water, spirits of turpentine, paraffine, malt vinegar, acetic acid, lemon juice, solution of soap and vegetable oiL The results were In one sense uniform; no single plate proved penetrable. The hard drills crumpled up under the pressure whenever they came In contact with the hard steel lamination, while the drills of the softer class were turned up or burned by abrasion. No matter what lubricant was tried the result was the same. With such a material as this in the market the “cracking* of safes is likely to become a decayed industry—Chicago Saturday Record.