This section is from the book "Machine Shop Work", by Frederick W. Turner, Oscar E. Perrigo, Howard P. Fairfield. Also available from Amazon: Machine shop work.
A growing apprehension of the possibilities of so safeguarding machines that the operator is reasonably sure that he incurs little risk of life or limb, would seem to render timely a few words on this subject.
It is well perhaps to note that no machine can be absolutely safeguarded and be operative. The danger to the operator can, however, with care, be reduced to a minimum, and much is now being done to safeguard such portions of machine tools as the gearing, the clutches, clutch couplings, belts, set screws, etc.
While the whole subject of "safety first" includes the building in which the machines are located, as well as the machines themselves, in general the machines should receive the first consideration. It is the truth that nothing can safeguard a machine against ignorance, bravado, or heedlessness on the part of the operative, and he must either educate himself or be educated to a point where he will voluntarily endeavor to protect himself against injury.
While it is usually true that the employe has very little direct authority in the matter of providing safeguards for the machines at which he may work, also in regard to the building in which he works, he may, by means of tactful suggestions made to the proper person, do much indirectly to promote the cause of safety. While usually the building in which the machinery is located must be taken as it is, many improvements can be made with safety first in view.
One of the common hazards is the danger of fire. This is a real danger to the employes' life if the building exceeds the height of a single story; and properly guarded stairways and fire escapes should provide easy exit. All exits should be designated by the word EXIT in prominent characters and all doors should open outward. Unobstructed passage to any and all exits should be maintained at all times, and all stairways should preferably be of a generous width and without bends or crooks. All stairways or other floor openings, as for example, elevator wells, should be safeguarded by suitable railings or nettings.
The transmission of power by means of shafting, pulleys, and belting, is a prominent hazard to safety unless it is properly safeguarded. Power driven gears, pulleys, and flywheels should be encased to at least 6 feet from the floor. All chain drives should be entirely encased, as should trains of gearing. Belts should be guarded to a height of at least 6 feet from the floor or any adjacent platform.
All line shafting, even if, as is usually the case, it is suspended from the ceiling, should be provided with necessary safeguards, as for example, smooth couplings, flush set screws, proper provision for belts when not on the pulleys, etc.
All switchboards should stand out from the wall to have a free and clear space sufficient for easy and safe inspection. This space should be enclosed with provision for padlocked entrances and exits. It should have also a prominent sign DANGER.
Wherever it is possible for the operative to accidentally make a dangerous ground connection, rubber matting should be provided and kept in a dry condition. High voltage lines should have prominently attached red signs stating the voltage. All switches should be guarded from accidental contacts.
All those machines which receive their power through a system of gearing, screws, spindles, pulleys, etc., should have all the working mechanisms covered. It will be noted that in essentially all of the production machines shown in this course, all moving parts have been encased wherever it was possible to do so without interfering with the convenient operation of the machine.
This is a very dangerous class of machinery and should receive special care in providing guards. The floor adjacent to such machinery as this should, as in the case of electrical apparatus, be covered with rubber matting.
Owing to the high rotative speed given to abrasive wheels in modern grinding, especial precautions should also be made to safeguard the workmen from a possible wheel explosion. While the manufacturer is painstaking in his efforts to safeguard his machines, it is not possible for him to prevent an ignorant or careless operative from rendering such safeguards inoperative.
In all operations which result in flying chips, the use of goggles is recommended. This includes such operations as snagging, chipping, hand grinding, and many other jobs.
All machines for punching, shearing, or pressing metals or other materials should, in addition to the ordinary safeguards, be provided with special safeguards at the working opening. These should absolutely prevent the closing of the machine while the operatives' hands are exposed to injury.
The art of safeguarding the workman is one that requires thought, ingenuity, and an unwillingness to ignore any little detail that will in any way achieve the end sought-Safety First.