Maximum guard openings on mechanical power presses

January 22, 1998
William H. Kincaid, CSP
Loss Control Consultant
Lockton Companies
[Recipient address omitted]
Dear Mr. Kincaid:
This is in response to your letter of February 16, regarding mechanical power presses and requesting an interpretation of Table O-10 (Maximum Guard Openings), found in the Occupational Safety and Health Administration's (OSHA's) Standard, 29 CFR 1910.217.
You inquired as to whether or not Table O-10 in §1910.217, refers to a "single vertical" measurement. The answer to your question is yes. The various openings listed in Table O-10 are such that for average size hands, an operator's fingers would not reach the point of operation. After installation of point of operation and before a job is released for operation, a check should be made to verify that the guard will prevent an operator's hands from reaching the point of operation.
The diagram that is part of the standard shows the accepted safe openings between the bottom edge of a guard and feed table at various distances from the danger line, or point of operation. There are only two measurements here: a distance from the point of operation, as you can see marked in the "horizontal axis," and the maximum width of the opening, which you call a vertical height in your letter.
Indeed this would be a width; if you consider a two-dimensional rectangle, the horizontal measurement would be the length, and the vertical would be the width. The nomenclature, however, is not significant here; it is the concept of preventing the operator's hands from reaching the point of operation that is significant. The length (not specified on Table O-10) could be adjusted to the necessary measurement to fit the parts to be fed into the press dies. That measurement is not specified.
Please consider an operator reaching into the guard opening. If the point of operation is very close to the guard opening, then the operator should not even be able to reach any of his/her fingers in the opening. However, if the hazard (point of operation) is so far away from the guard opening, almost three feet, then even an arm-length should not be able to reach the hazard with a 6" opening. The width is limited to 6 inches, since the standard was intended to prevent employees from reaching into the point of operation through the opening with their arms, body, head, etc. The length (horizontal measurement) of the opening is not limited anywhere in the standard.
Therefore, what you call the horizontal measurement, namely, the length, has no limitations in the standard, so long as your barrier guard and or length of the opening is not creating any other hazard, (i.e., pinch points, etc).
Thank you for your interest in occupational safety and health. If you need further assistance, please contact [the Directorate of Enforcement Programs at (201) 693-2100].
Sincerely,
John B. Miles, Jr., Director
[Directorate of Enforcement Programs]
[Corrected 6/10/04]