Portable circular saw guarding

Under 1910.243(a)(1)(i) the saw must have both upper and lower guards: the upper guard must cover the saw to the depth of the teeth (except for the minimum arc needed to tilt the base for bevel cuts), and the lower guard must cover the saw to the depth of the teeth and automatically and instantly return to cover the blade when the tool is withdrawn from the work. See the requirement in 1910.243(a)(1)(i).

Under 1910.243(a)(1)(ii) the guard requirement in 1910.243(a)(1)(i) does not apply to circular saws used in the meat industry for meat cutting purposes. See 1910.243(a)(1)(ii).

Under 1910.243(a)(1)(i) the upper guard must shield the blade up to the deepest point of the cutting teeth except only where a small arc must remain exposed to let the base be tilted for bevel cuts; that arc should be the smallest amount necessary to make the bevel adjustment. See 1910.243(a)(1)(i).

Under 1910.243(a)(1)(i) the lower guard must cover the saw to the depth of the teeth during cutting and must automatically and instantly return to the covering position when the tool is withdrawn from the work. See 1910.243(a)(1)(i).

Under 1910.243(a)(4) all cracked saws must be removed from service. See 1910.243(a)(4).

Under 1910.243(a)(5) portable electric powered tools must meet the electrical requirements of Subpart S of 29 CFR part 1910 (grounding and other electrical safety requirements). See 1910.243(a)(5) and the general 1910 link.

Under 1910.243(a)(2)(i) all hand-held power-driven circular saws with blade diameters greater than 2 inches must be equipped with a constant pressure switch or control that shuts off power when pressure is released. See 1910.243(a)(2)(i).

Under 1910.243(a)(2)(i) hand-held circular saws with blades greater than 2 inches must use a constant pressure switch, so a lock-on is not permitted for those saws; paragraph (a)(2)(ii) allows lock-on controls only for certain other powered tools if turnoff can be done by a single motion of the same finger(s) that turn it on. See 1910.243(a)(2)(i) and 1910.243(a)(2)(ii).

Under 1910.243(a)(2)(iv) the operating control must be located so as to minimize the possibility of accidental operation if such accidental operation would create a hazard to employees. See 1910.243(a)(2)(iv).

Under 1910.243(a)(2)(i) all hand-held gasoline powered chain saws must be equipped with a constant pressure throttle control that will shut off power to the saw chain when the pressure is released. See 1910.243(a)(2)(i).

Under 1910.243(c)(1)(i)(b) mounted wheels used in portable operations 2 inches and smaller in diameter are excepted from the general guarding requirements of paragraph (c)(1). See 1910.243(c)(1)(i)(b) and the general portable abrasive wheel requirements in 1910.243(c)(1).

Under 1910.243(c)(1)(ii)(a) a safety guard must cover the spindle end, nut, and flange projections and be mounted to stay aligned with the wheel; its fastenings must be stronger than the guard. See 1910.243(c)(1)(ii)(a).

Under 1910.243(c)(3) and (c)(4) the maximum angular exposure of the grinding wheel periphery and sides for safety guards on portable grinders shall not exceed 180°, and the top half of the wheel must be enclosed at all times; for vertical portable grinders the guard must be between the operator and the wheel. See 1910.243(c)(3) and 1910.243(c)(4).

Under 1910.243(c)(5)(i) and cross-referenced 1910.215(d)(1) the user must closely inspect and sound (ring test) the wheel immediately before mounting to ensure it was not damaged in transit, storage, or otherwise. See 1910.243(c)(5)(i).

Under 1910.243(a) the unused run of a sanding belt must be guarded against accidental contact. See 1910.243(a).

Under 1910.243(c)(5)(ii) you must check the machine spindle speed before mounting the wheel to ensure it does not exceed the maximum operating speed marked on the wheel. See 1910.243(c)(5)(ii).

Under 1910.243(c)(5)(iii) all contact surfaces of wheels, blotters, and flanges must be flat and free of foreign matter, and under 1910.243(c)(5)(iv) when a bushing is used in the wheel hole it must not exceed the width of the wheel and must not contact the flanges. See 1910.243(c)(5)(iii) and 1910.243(c)(5)(iv).

Under 1910.243(a)(2)(iii)(a) other hand-held powered tools (for example small platen sanders, routers, planers, and jig saws with small shanks) may be equipped with either a positive on-off control or the constant pressure controls described in paragraphs (a)(2)(i) and (ii). See 1910.243(a)(2)(iii)(a).

Under 1910.243(a)(2)(iii)(d) the term "nominal" means ±0.05 inch when used to describe blade shank width for saber, scroll, and jig saws with nonstandard blade holders. See 1910.243(a)(2)(iii)(d).

Yes. Under 1910.243(d)(2)(ii)(a), the muzzle end must be designed so suitable protective shields, guards, jigs, or fixtures (designed and built by the tool manufacturer) can be mounted perpendicular to the barrel, and a standard spall shield must be supplied with each tool.

• Practical tip: Keep the manufacturer-supplied spall shield in service and replace it if damaged.

Reference: 1910.243(d)(2)(ii)(a).

Yes. 1910.243(d)(2)(ii)(b)(1) requires that the tool be designed so it will not, in ordinary usage, propel or discharge a stud, pin, or fastener during loading, preparation to fire, or if the tool is dropped while loaded.

• Practical tip: Train operators on safe loading procedures and store tools unloaded to avoid accidental discharge.

Reference: 1910.243(d)(2)(ii)(b)(1).

Yes. 1910.243(d)(2)(ii)(b)(2) requires that firing be dependent on at least two separate and distinct operations by the operator, with the final firing movement separate from bringing the tool into the firing position.

• Practical tip: Use tools with a contact/trigger sequence that prevents single-action firing; do not defeat manufacturer safety features.

Reference: 1910.243(d)(2)(ii)(b)(2).

Yes. 1910.243(d)(2)(ii)(c) requires the tool to be designed so it is not operable other than against a work surface, and only when the operator is holding the tool against the work surface with a force at least 5 pounds greater than the total weight of the tool.

• Practical tip: Ensure contact tips and safety interlocks are intact; do not bypass the contact-pressure feature.

Reference: 1910.243(d)(2)(ii)(c).

Yes. 1910.243(d)(2)(ii)(d) requires that tools be designed so positive means of varying the power are available (as part of the tool or as an auxiliary), allowing the operator to select a power level adequate to perform the work without excessive force.

• Practical tip: Match the power level to the base material and fastener to reduce ricochet or over-penetration hazards.

Reference: 1910.243(d)(2)(ii)(d).

Yes. 1910.243(d)(2)(ii)(e) requires the tool be designed so that all breeching parts are reasonably visible to allow checks for foreign matter.

• Practical tip: Before each use, visually inspect breech and barrel for obstructions or debris.

Reference: 1910.243(d)(2)(ii)(e).

Yes. 1910.243(d)(3)(iii) prohibits use of any load that will cause a fastener to have a mean velocity in excess of 300 feet per second when measured 6.5 feet from the muzzle; individual test firings in a series must not exceed 300 ft/s by more than 8 percent.

• Practical tip: Only use loads and fasteners specified by the tool manufacturer and check load markings to ensure compliance.

Reference: 1910.243(d)(3)(iii).

Yes. 1910.243(d)(3)(iv) requires that fasteners used in these tools must be those specifically manufactured for use in such tools.

• Practical tip: Do not substitute homemade or mismatched fasteners; use only manufacturer-approved fasteners.

Reference: 1910.243(d)(3)(iv).

The operator must inspect the tool to ensure it is clean, moving parts operate freely, and the barrel is free from obstructions, as required by 1910.243(d)(4)(i).

• Practical checklist: clean exterior, verify safety interlocks, check barrel for obstructions, and confirm shields/guards are present.

Reference: 1910.243(d)(4)(i).

They must immediately stop using the tool until it is properly repaired, as required by 1910.243(d)(4)(ii).

• Practical tip: Tag defective tools out of service and follow the manufacturer's repair instructions before returning to use.

Reference: 1910.243(d)(4)(ii).

Only immediately prior to the intended firing time. 1910.243(d)(4)(iii) states tools shall not be loaded until just prior to firing.

• Practical tip: Load at the work location and only when the operator is ready to use the tool.

Reference: 1910.243(d)(4)(iii).

No. Neither loaded nor empty tools are to be pointed at any workmen, and 1910.243(d)(4)(iv) prohibits loading tools unless being prepared for immediate use and forbids leaving an unattended tool loaded.

• Practical tip: Keep tools unloaded when not in immediate use and always control the muzzle direction during handling.

Reference: 1910.243(d)(4)(iv).

Follow the misfire procedure: hold the tool in the operating position for at least 30 seconds, try to operate again, wait another 30 seconds if it still does not fire, then remove the explosive load strictly per the manufacturer's instructions, as required by 1910.243(d)(4)(v).

• Practical tip: Train operators on the manufacturer’s misfire removal steps and ensure safe handling during the entire procedure.

Reference: 1910.243(d)(4)(v).

Yes. 1910.243(d)(4)(vii) prohibits driving fasteners into very hard or brittle materials (for example, cast iron, glazed tile, surface-hardened steel, glass block, face brick, hollow tile). 1910.243(d)(4)(viii) requires avoiding driving into easily penetrated materials unless backed to prevent the fastener from passing completely through and creating a flying-missile hazard.

• Practical tip: Verify the base material and back up thin or hollow substrates before driving fasteners.

References: 1910.243(d)(4)(vii), 1910.243(d)(4)(viii).

Fasteners shall not be driven closer than 3 inches from an unsupported edge or corner in materials like brick or concrete, or closer than one-half inch from an unsupported edge or corner in steel, unless a special guard, fixture, or jig is used, as stated in 1910.243(d)(4)(ix)(a). An exception allows driving certain fasteners when fastening other materials (for example, attaching a 2- by 4-inch wood section to concrete) using a fastener no greater than 7⁄32-inch shank diameter not closer than 2 inches from the unsupported edge, per 1910.243(d)(4)(ix)(b).

• Practical tip: Measure and mark safe distances before firing and use fixtures or guards when working near edges.

References: 1910.243(d)(4)(ix), 1910.243(d)(4)(ix)(b).

No. 1910.243(d)(4)(x) requires that fasteners shall not be driven through existing holes unless a positive guide is used to secure accurate alignment.

• Practical tip: Use alignment jigs or guides when driving into pre-drilled or existing holes.

Reference: 1910.243(d)(4)(x).

Yes. 1910.243(d)(4)(xiii) requires that all tools be used with the correct shield, guard, or attachment recommended by the manufacturer.

• Practical tip: Keep manufacturer manuals on hand and replace any missing guards before use.

Reference: 1910.243(d)(4)(xiii).

Power lawnmowers (walk-behind, riding-rotary, and reel types) must be guarded in accordance with the machine guarding requirements in 1910.212, as stated in 1910.243(e)(1).

• Practical tip: Ensure blade enclosures and discharge guards meet the general machine guarding rules in 1910.212 and that guards are present and functional.

References: 1910.243(e)(1), 1910.212.

The mower blade must be enclosed except on the bottom and the enclosure must extend to or below the lowest cutting point in the lowest blade position, per 1910.243(e)(2)(i). Openings intended for grass discharge are limited in vertical angle to 30° for certain units per 1910.243(e)(2)(iii), and the total effective opening area is limited to 1,000 square degrees for widths less than 27½ inches or 2,000 square degrees for widths 27½ inches or over as specified in 1910.243(e)(2)(iv).

• Practical tip: Maintenance and replacements must preserve enclosure dimensions and discharge opening limits to remain compliant.

References: 1910.243(e)(2)(i), 1910.243(e)(2)(iv), 1910.243(e)(2)(iii).

If guards must be removed to install a catcher assembly, the mower must have warning instructions affixed near the opening stating the mower shall not be used without either the catcher assembly or the guard in place, and the instruction manual must state the mower shall not be used without the catcher or guard, as required by 1910.243(e)(2)(ii)(a) and 1910.243(e)(2)(ii)(c).

• Practical tip: Keep warning labels visible and ensure operator manuals are available and followed.

References: 1910.243(e)(2)(ii)(a), 1910.243(e)(2)(ii)(c).

Blade(s) must stop rotating within 15 seconds after declutching or shutting off power, as required by 1910.243(e)(2)(vii).

• Practical tip: Test blade stop times during maintenance and repair any braking systems that exceed the 15‑second limit.

Reference: 1910.243(e)(2)(vii).

Yes. 1910.243(e)(2)(ix) sets the maximum tip speed of any blade at 19,000 feet per minute.

• Practical tip: Verify replacement blades and engine speeds do not push tip speed above this limit.

Reference: 1910.243(e)(2)(ix).