When Is a Point-of-Operation Guard Required on a Power Press? The Quarter-Inch Rule Explained

Under 29 CFR 1910.217(c)(1)(i), the employer must provide, and make sure employees use, point-of-operation guards or properly applied and adjusted point-of-operation devices on every operation performed on a mechanical power press. The only carve-out is in (c)(1)(ii): the requirement does not apply when the point-of-operation opening is one-fourth inch or less. Above that, any guard you rely on must respect the maximum opening widths of Table O-10, which grow as the guard moves farther from the hazard.

The general rule: a guard or a device on every operation

Paragraph (c)(1)(i) puts the responsibility squarely on the employer: it is not enough to buy a guard, you have to insure its usage. The rule covers every operation, not just production runs. OSHA's 1979 directive STD 01-12-024 makes the point for die setters: when they run test and production parts, set dies or troubleshoot, they must be protected by point-of-operation guards or devices, and failing to do so is cited under 1910.217(c)(1)(i).

Two definitions in 1910.211(d) frame the rule. The point of operation is the area of the press where material is actually positioned and work is being performed during any process such as shearing, punching, forming, or assembling. A guard is a barrier that prevents entry of the operator's hands or fingers into the point of operation. A device is a press control or attachment that restrains, withdraws, or detects the operator's hands, or that prevents or stops a stroke when the sensing field is broken.

The quarter-inch exception in 1910.217(c)(1)(ii)

The regulatory text is short: the requirement of (c)(1)(i) shall not apply when the point of operation opening is one-fourth inch or less, with a cross-reference to Table O-10. The logic is physical. If the gap into the die area is 1/4 inch or smaller, fingers cannot get in, so the opening itself is the protection. That is why the first line of Table O-10 also uses 1/4 inch as its tightest opening.

• 0.2-inch opening: below 1/4 inch, so the guard-or-device requirement of (c)(1)(i) does not apply to that opening.
• 0.25-inch opening: exactly one-fourth inch, still within the exception (the text says one-fourth inch or less).
• 0.3-inch opening: above 1/4 inch, so you are back to the general rule and need a guard that meets Table O-10 or a properly applied device.

Measure the opening as it exists during the actual operation, not on the drawing. Paragraph (d)(4) shows how seriously OSHA treats that quarter-inch line: a guide post located in the immediate vicinity of the operator that is separated from its bushing by more than one-fourth inch is considered a point-of-operation hazard and must be protected under paragraph (c).

Table O-10: how wide a guard opening may be at each distance

When the opening is larger than 1/4 inch, a point-of-operation guard must, among other things, conform to the maximum permissible openings of Table O-10 (1910.217(c)(2)(i)(b)). The table pairs the distance of the opening from the point-of-operation hazard with the maximum width allowed at that distance. The farther the guard sits from the danger line, the larger the opening can be, because a hand reaching through it cannot reach the hazard.

The explanation that accompanies the table in the regulation describes the geometry: the openings are measured between the bottom edge of the guard and the feed table at various distances from the danger line. The minimum guarding line sits one-half inch from the danger line, which is why the table starts at 1/2 inch. A clearance line marks the distance needed to prevent contact between the guard and moving parts. The openings are set so that, for average size hands, an operator's fingers won't reach the point of operation.

Worked example: reading the table

Suppose your stock needs a 1-inch feed slot. In Table O-10, 7/8 inch is the largest width allowed in the 6 1/2 to 7 1/2 inch band, and 1 1/4 inches is allowed in the 7 1/2 to 12 1/2 inch band. A 1-inch slot exceeds 7/8, so it only fits the 7 1/2 to 12 1/2 inch band: the guard face must sit at least 7 1/2 inches from the point-of-operation hazard. If the layout does not allow that, narrow the slot or move to a device. A 5/8-inch slot, by contrast, is acceptable from 3 1/2 inches out.

The regulation adds a practical step: after installing point-of-operation guards and before a job is released for operation, a check should be made to verify that the guard will prevent the operator's hands from reaching the point of operation. If you are unsure which band applies to a given slot, the machine guarding base returns the Table O-10 row together with the paragraph that requires it.

What else a compliant guard must do

Respecting Table O-10 is only one of six requirements listed in 1910.217(c)(2)(i). Every point-of-operation guard must:

1. Prevent entry of hands or fingers into the point of operation by reaching through, over, under or around the guard.
2. Conform to the maximum permissible openings of Table O-10.
3. Create no pinch point of its own between the guard and moving machine parts.
4. Use fasteners not readily removable by the operator.
5. Facilitate its own inspection.
6. Offer maximum visibility of the point of operation consistent with the other requirements.

The type of guard also comes with mounting rules. A die enclosure guard is attached to the die shoe or stripper in a fixed position. A fixed barrier guard is attached securely to the press frame or bolster plate. An interlocked press barrier guard is interlocked with the clutch control so the clutch cannot be activated unless the guard is in a position that conforms to Table O-10, and its hinged sections cannot be used for manual feeding. An adjustable barrier guard must be adjusted and operated in conformity with Table O-10, and adjustments may only be made by authorized personnel who know Table O-10. Finally, a point-of-operation enclosure that does not meet Table O-10 may only be used together with point-of-operation devices (c)(2)(vii).

When a guard won't work: devices and the safety-distance formula

If the job requires the operator to feed by hand inside the die area, the alternative is a properly applied device under (c)(3): gates or movable barriers, presence-sensing devices, pull-outs, holdouts or restraints, two-hand controls or two-hand trips. Two rules trip up many shops. A presence-sensing device may not be used on machines using full revolution clutches ((c)(3)(iii)(a)), and the sweep device may not be used for point-of-operation safeguarding at all ((c)(3)(v)).

For presence-sensing devices and two-hand controls, the device must be mounted beyond a minimum safety distance: Ds = 63 inches/second × Ts, where 63 in/s is the hand speed constant and Ts is the stopping time of the press measured at approximately the 90° position of crankshaft rotation. As an illustration only, a press with a measured stopping time of 0.20 second gives 63 × 0.20 = 12.6 inches, so the sensing field or two-hand control must be more than 12.6 inches from the point of operation. Use your own measured stopping time, never an assumed one.

Common mistakes on the shop floor

• Treating the quarter-inch exception as covering the whole press when only one opening is 1/4 inch or less; every other access route still needs protection.
• Measuring the opening once at setup and never again after a die change or guard adjustment.
• Letting operators adjust an adjustable barrier guard, when (c)(2)(vi) reserves adjustments to authorized personnel who know Table O-10.
• Installing a light curtain on a full revolution clutch press.
• Leaving the sides and back of the die area open when a light curtain protects only the front; (c)(3)(iii)(f) requires guards on all areas of entry not protected by the device.
• Relying on pliers or push sticks instead of a guard or device.

Each of these questions can be put directly to the OSHA machine guarding knowledge base, which answers with the paragraph it relies on, for example: "Can a presence-sensing device be used as the point-of-operation safeguard on a mechanical power press with a full revolution clutch?". The authoritative text remains the eCFR version of 1910.217, which displayed no changes after January 3, 2017 when the base was compiled (eCFR up to date as of October 1, 2026).