Modification and improvement of drill bits of one and two diameters that allow the depth of the drills and countersinks to be graduated beforehand without the danger of exceeding the depths that they must reach in them. (Machine-translation by Google Translate, not legally binding)

摘要

It is claimed, THE MODIFICATION AND IMPROVEMENT IN THE BITS OF ONE AND TWO DIAMETERS, WHICH ALLOW GRADUAL IN ADVANCE THE DEPTH OF DRILLS AND HAZELNESS, WITHOUT THE DANGER OF REBASATING THE DEPTHS THAT MUST BE ACHIEVED IN THEM. (Machine-translation by Google Translate, not legally binding)