Directive: Mechanical Power Presses

3 Lafayette Road N., St. Paul, MN 55155 • 651-284-5050 • www.dli.mn.gov

MNOSHA Instruction STD 1-12.24A

August 12, 2015

Updated to Accessible form 7-25-2024

Subject: Mechanical Power Presses -- 1910.217

Purpose:

To guide enforcement of 1910.217 Mechanical Power Presses

Scope: This instruction applies MNOSHA-wide. This document covers the requirements for

Construction, Safeguarding, Diesetting, Inspection, Injury Reporting, and Presence Sensing Device Initiation for

mechanical power presses. It also contains two Appendices which include the Mechanical Power Press

Inspection Checklist and the Report Of Injury To Employee Operating A Mechanical Power Press form.

Reference:

The following documents are used as a reference and as a basis for the recommended ACTION section of this

instruction:

. Federal OSHA Instruction STD 01-12-024 https://www.osha.gov/enforcement/directives/std-01-12-024

Clarification and Interpretation of 29 CFR 1910.217, Mechanical Power Press, as Applies to the

Safeguarding, dated July 30, 1979, specifies requirements for safeguarding die setters at the point of

operation and provides alternatives for spring-loaded turnover bars.

B. ANSI B 11.1-2009, "Safety Requirements for Mechanical Power Presses" provides guidance on the intent

and application of the OSHA power press standards.

C. ANSI B 11.1-1971, "American National Standard for Machine Tools – Safeguarding When Referenced By

The Other B11 Machine Tool Safety Standards – Performance Criteria For The Design, Construction,

Care, And Operation.” [This is the source document for section 1910.217.]

D. Federal OSHA Instruction STD 01-12-021, https://www.osha.gov/enforcement/directives/std-01-12-021

Mechanical Power Presses, Clarifications, dated 10/30/78, provides a guide to aid in the recognition of

mechanical power press point of operation hazards and provides uniform clarification of definitions,

guards, devices, and methods of safeguarding.

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E. Federal OSHA Instruction STD 01-12-020, https://www.osha.gov/enforcement/directives/std-01-12-020

Mechanical Power Presses Single Stroke Mechanism Requirements, dated 10/30/78, covers single-

stroke mechanism requirements on full revolution power presses.

Cancellation:

This instruction supersedes MNOSHA Instruction STD 1-12.24, dated March 4, 2013.

Action:

A. Guarding and Construction, General

1. Single-Stroke Mechanism

a. Single-stroke mechanisms will not be required on full revolution clutch mechanical power

presses if they are operated only in the continuous mode and the point of operation is fully

enclosed by a proper point of operation guard.

Note: Die-setters must be protected by point of operation devices (e.g. two-hand controls)

when guards are not in place, and the press must otherwise meet the applicable requirements

of 1910.217.

b. A press control system with an anti-repeat feature built in will provide single-stroke capability

and meet the intent of the requirement for a single-stroke mechanism.

2. Foot Pedal Guards

OSHA standards for foot pedals or foot controls of mechanical power presses require that they be

protected to prevent operation from falling or moving objects, or by accidental

stepping onto the pedal. The illustrations in the ANSI standards show as an

acceptable guard one that covers the top of the pedal. However, we should recommend guards that

enclose the sides as well, such as the one shown to the far right.

3. Full versus Part Revolution Clutch Presses and Direct Drive Presses

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a. The determination of whether a press has a full or a part revolution clutch is dependent on the

type of physical clutch it has, not on the way it operates. Some part revolution clutch presses

will operate as full revolution, but are still part revolution presses and must comply with all the

part revolution control and safeguarding requirements for the safety of the operator.

b. Recognition of the two clutch types can usually be made from observation.

i. Full revolution clutches:

1) Have a mechanical pin, “dog”, collar, or rolling key that couples the crankshaft to the

rotating flywheel when engaged. There is a cam or similar mechanism to disengage the

clutch. Once engaged, these clutches will make a full revolution before the cam

disengages it.

2) May not have a hose connected to the end of the flywheel. If it does, the hose is

relatively small compared to the one on a part revolution clutch and is intended for

lubrication. It may only be about the diameter of an average finger.

ii. Part revolution clutches:

1) Have air operated friction clutches. These are discs that have material similar to brakes

on the sides. These are similar to the clutch in a car with a standard transmission and

may be engaged or disengaged at any point in their stroke.

2) May function as a full revolution clutch even though the clutch can be engaged or

disengaged during the stroke. Regardless, they are still part revolution clutches and

must meet all the control and safeguarding requirements of part revolution clutch

presses.

3) Will have an air line coming into the clutch end of the flywheel end of the press. This air

line is approximately the diameter of a garden hose and is much larger than the

lubrication line that might be used on a full revolution press. The air line will have a

solenoid operated valve that causes the clutch to engage when actuated.

4) May be started or stopped at any point in its stroke and is to have an emergency stop

button to accomplish this.

a) Some older part revolution clutch presses may not have had the emergency stop

included in their controls. These should be cited under 1910.217(b)(7)(ii).

b) The existence of an emergency stop button should not be used as a sole means of

determining the type of clutch on a press. Some full revolution clutch presses have

had an emergency stop button installed, but these do not function in the manner

required for a part revolution press. These buttons would not disengage the clutch

and their existence does not mean that the clutch is part revolution.

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iii. Direct drive systems.

The direct drive press does not have a clutch. Instead, it uses a motor to directly control the

motion and stopping of the press slide. These direct drives match the operational

characteristics of part-revolution clutches because the driving power may be interrupted

during the cycle of the press.

4. Air Counterbalance Cylinders

A check valve on the press, downstream of the regulator, will meet the requirement for a means to

prevent failure of capability (sudden loss of pressure) in event of air supply failure as required in

1910.217(b)(9)(v).

B. Safeguarding the Point Of Operation (POO)

1. Citing point of operation safeguarding deficiencies:

a. If no safeguarding is provided/used: Cite only 1910.217(c)(1)(i). It covers the employer’s

responsibility to provide and insure the usage of POO guards or properly applied and adjusted

POO devices on every operation performed. Grouping with one or more specification standards

from 1910.217(c)(2) or (3) should not be done where no safeguarding was used.

b. If deficient safeguarding is provided/used: Where POO guards or devices do not comply,

1910.217(c)(1)(i) and the more specific standard are to be grouped and cited as a single item.

This includes, but is not limited to the standards contained in 1910.217(c)(2), (c)(3), (b)(6), and

(b)(7)(v). The latter are specification standards and are to be cited only in conjunction with

1910.217(c)(1)(i). Additionally, 1910.217(c)(5)(i) and/or 1910.217(c)(5)(iii) should be grouped

with 1910.217(c)(1)(i).

For example, cite 1910.217(c)(1)(i) and (c)(3)(viii)(c) for inadequate safety distance between the

two-hand trip and the point of operation on a full revolution press.

2. Two-hand trips and controls are required to be fixed in position. It is not acceptable to mark the

safety distance on the floor and maintain the two-hand trip/control pedestal outside of this

line/mark. However, if the pedestal is movable, and a positive means is provided to ensure it cannot

be moved within the required safety distance, this will not be cited if no hazard is presented. One

method of doing this could be to have a sufficiently large base on the pedestal so the buttons

cannot physically be located within the safety distance.

a. Concurrent operation of two-hand controls and two-hand trips means they must exist in an

actuated condition at the same time according to the definition in 1910.211(d)(8). ANSI B11.1,

the source document for this standard, states in the explanatory information that:

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The use of the word concurrent is intended to exclude any inference that a simultaneous moment

of actuation must exist between the operations of the individual two hand controls.

We cannot enforce a timed interval as a requirement of the two-hand trips/ controls. However,

this is an important safety feature as it prevents a control from being tied down, and protects

against a failure of one of the actuating means. Without this feature the press can cycle if a

pushbutton is intentionally or inadvertently depressed and, at some later time, the other is

depressed.

During function testing of the two-hand trips/controls OSHIs should check for an anti-tiedown

feature requiring essentially simultaneous operation of the two-hand trips/ controls. The OSHI

should recommend to employers that the simultaneous feature be voluntarily provided,

inspected, and maintained to reduce the risk of injury.

There is no obligation that an “anti-tiedown” feature be provided, although the use of tie-downs

and bridges are in violation of the requirement for “concurrent” use of both hands and should

be cited.

b. Safety Distance: To cite a full revolution clutch press for safety distance under

1910.217(c)(3)(viii)(c), the OSHI's should clearly state the:

i. Press manufacturer and model number.

ii. Number of revolutions of the flywheel per minute; or the number of strokes per minute

when running in automatic continuous mode (This does not mean cycled repeatedly).

iii. Number of engaging points of the clutch.

a) Partial list of Engagement Points – Full Revolution Presses:

# of Engagement Points

Press Manufacturer

Niagara – only

Bliss, Minster, Press Rite

Alva Allen, Johnson, Verson, Bliss, Clearing, Cleveland,

Consolidated, Danly, Diamont, Federal, Minster, Ferracute, L & J,

Toledo, Perkins, Robinson, Rockford, Rousselle, V & O, Walsh,

Williams/White

Alva Allen, Kenco, Benchmaster, Perkins, Gilro, Pressrite

Benchmaster, Famco, Gilro

There is some overlap in the above list and may not be correct for all press makes and models.

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iv. The distance in inches between each two-hand trip and the nearest crushing/ shearing

hazard in the die area.

a. NOTE: The OSHI should inform the employer of other ways to abate the citation, such as the

use of other point of operation guards or other properly applied and adjusted point of operation

devices that would be appropriate.

3. Hand Feeding Tools: Hand feeding tools are not to be used in lieu of point of operation guard or

devices. However, when feasible, OSHIs should recommend the use of hand tools for placing or

removing parts in and from the dies to reduce employee exposure to the point of operation hazards.

4. Additional requirements for safe-guarding under 1910.217(c)(5):

Standard 1910.217(c)(4) specifies that hand feeding tools are not a point of operation guard or

device and are not to be used in lieu of the guards or devices required in this section. This standard

was intended to apply to the paragraphs preceding 1910.217(c)(4), and not to 1910.217(c)(5).

Therefore, if the employer enforces and the employee faithfully uses hand feed tools to load and

unload a part revolution clutch press, and hands are not placed in the dies for feeding or removing

parts, the employer should not be cited under 1910.217(c)(5)(i) and (iii) which requires a brake

monitor, control reliability, and a dual air valve.

Note: OSHI’s are not to advise the use of hand feeding tools as a method of abating citations

under the requirements of 1910.217(c)(5). They should inform the employer of other methods

of abatement, such as the use of point of operation guards or devices that do not require

compliance with 1910.217(c)(5)(i) and (iii). This could include point of operation guards, a Type-

A gate device, pull-outs or restraints.

C. Design, Construction, Setting And Feeding Of Dies

1. Protection of Die-setters (A die-setter is defined in 1910.211(d)(11)).

a. Diesetting Procedure: 1910.217(d)(9)(i) specifies requirements for the protection of diesetters at

the point of operation. It requires employers to proactively establish a diesetting procedure to

ensure compliance with 1910.217(c). The procedure is not required to be in writing.

i. Diesetters shall be protected at the point of operation by a proper point of operation guard

or device on every operation performed on a mechanical power press. This means die-

setters are covered by the provisions of 1910.217(c) when running test or production parts,

die-setting, or troubleshooting on a power press.

ii. It is not acceptable for diesetters to operate the press without point of operation guards or

devices (except as provided below for "Jog" or “Inch” operation.) Since guards can’t

normally be used during die-setting operation of the press, point of operation devices (e.g.

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two-hand trips or controls) are typically needed for safeguarding the diesetter on both full

and part-revolution clutch presses.

iii. The requirements of 1910.147 apply to portions of the die setting procedure where the die

setter is not positioning or testing the set up.

2. Turnover Bar Options:

a. Spring loaded turnover bars are required by 1910.217(d)(9)(ii).

b. The current ANSI B11.1 standard merely requires a means to ensure removal from the bar hole

before the press can be energized. In addition to spring loading, it also allows for the use of bar

storage pockets that incorporate an interlock switch. Either option will comply with the intent of

the OSHA standard.

Note that the interlock switch/plug is to ensure that the control circuit for the press is open

when the turnover bar is not in place. This interlock does not replace the need for locking out

the main electrical power under 1910.147.

c. When citing 1920.217(d)(9)(ii) the OSHI should allow for the alternative within the wording of

the AVD. For example:

"The employer did not provide spring-loaded or interlocked turnover bars on ... "

3. Diesetter Safety With Turnover Bars: Most full-revolution clutch presses have barring holes in the

flywheel or crankshaft and are to be considered safeguarded if a proper turnover bar (spring-loaded

or interlocked) is used with the:

a. Main electrical power disconnect switch turned off (or the plug disconnected), the flywheel

brought to rest, and

b. Electrical, pneumatic, gravity, or other energy sources are locked out or isolated as required

under 1910.147.

4. Diesetter Safety With Jog or Inch Buttons:

a. Full Revolution Clutch Presses: Some larger full-revolution presses are not provided with a

means for turnover bar operation. In this case, the point of operation would be considered

safeguarded during setup if:

i. A momentary contact Jog pushbutton is used to impart an intermittent motion of the slide

(ram) by momentary operation of the drive motor, after the clutch is engaged with the

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flywheel at rest. (This Jog pushbutton is only to be used to cause a partial, not a full, cycle of

the press.)

ii. The Jog control must require two-hand operation; or be a single control protected against

accidental actuation and so located that the worker cannot reach into the point of operation

while operating the single control.

Failure to safeguard the die-setter on a full revolution press in accordance with the above

shall be cited under 1910.217(d)(9)(i), 1910.217(c)(1)(i), and/or 1910.147 as appropriate.

b. Part-Revolution Clutch Presses.

i. An Inch-operating-means that meets the requirements of 1910.217(b)(7)(iv) is a satisfactory

means of safeguarding during setup. Improper inch controls that allow the employee to be

exposed are to be cited under 1910.217(b)(7)(iv).

ii. Note that “Inch" controls or the “Inch” operating mode do not provide all the features of

two-hand controls and may not be used for "Single-Stroke" or "Continuous" operation. Use

of the Inch-operating-means by the operator for regular production use is improper and is

to be cited under 1910.217(c)(1)(i).

Inch-operating-means are not provided with anti-repeat features that meet the

requirements of the standards. This allows the two-hand controls to be tied down in

continuous operation. Inch-operating-means also allow the press to be operated with the

drive motor in reverse which reverses the rotary limit switches. This means the press will

not stop during the die-closing portion of the stroke if the two-hand controls are released.

iii. The “Bar” push button is sometimes used as a means of jogging a part revolution clutch

press instead of using the proper Inch-operating-means. If the point of operation is exposed

to the operator(s) or other employees, a citation of 1910.217(c)(1)(i) is to be issued.

D. Inspection, Maintenance, And Modification Of Presses

1. Power press inspections: Only persons knowledgeable with applicable power press construction,

safeguarding, and diesetting requirements in 1910.217 (or the current/equivalent ANSI) standard

should perform inspections.

2. Retention of Inspection Records: The standard for power press inspection records under

1910.217(e)(1)(i) and (ii), and (c)(3)(iv)(d) for pull-outs, does not specify a duration for records

retention. We should recommend that they be maintained for at least 6 months following the end

of the year to which they relate. This will allow the employer to demonstrate that they are

conducting proper and timely inspections of their presses.

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E. Reports Of Injuries To Employees

1. Employers are required to report to MNOSHA all point of operation injuries to employees operating

mechanical power presses. Employers are required to make the report by telephone or send a

written report to MNOSHA within thirty calendar days of the accident. Documents which establish

press point of operation injuries not reported will normally be cited under 1910.217(g)(1). We will

not cite employers who provide evidence that they have filed the injury report with Federal OSHA.

If the power press injury meets the criteria for reporting a serious injury under 1904.39, the

employer must comply with the timelines in 1910.39.

2. The attached AppendixA is a form the employer may use to meet the reporting requirement for

mechanical power press point of operation injuries. This form is available in a fill-in PDF form on the

MNOSHA website.

3. All reports of point of operation injuries will be referred to the person on phone duty and will be

processed as a report of a serious injury (see Intake Processing Manual, chapter 3). If the employer

has completed the form (Appendix A) or has made a report to Federal OSHA in writing, the person

on phone duty will scan the form or report into the Serious/Fatal Log record.

F. Presence Sensing Device Initiation (PSDI)

PSDI requires certification and validation by an OSHA recognized third-party validation organization.

There are no such OSHA recognized third-party validation organizations at this time so this method of

operating mechanical power presses is not permitted.

James Krueger, Director MNOSHA Compliance

For the MNOSHA Management Team

Distribution: OSHA Compliance and WSC Director

Attachments: Appendix A - Report Of Injury To Employee Operating A Mechanical Power Press

NOTICE: Minnesota OSHA Directives are used exclusively by MNOSHA personnel to assist in the administration of the OSHA program and in the proper

interpretation and application of occupational safety and health statutes, regulations, and standards. They are not legally binding declarations and they

are subject to revision or deletion

at any time without notice.

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Appendix A: Report Of Injury To Employee Operating A Mechanical Power

Press

29 CFR 1910.217(g)(1)

The employer shall, within 30 days of the occurrence, report to … the State agency administering a plan approved

by the Assistant Secretary of Labor for Occupational Safety and Health, all point of operation injuries to

operators or other employees. The following information shall be included in the report:

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