Caldwell Non-Marring Portable Beam Clamp

Non-Marring Portable Beam Clamp — Protects Coated Beam Finishes During Lifting

The Caldwell RENFROE Model NMBC is a portable locking beam clamp engineered specifically for use on coated or finish-sensitive steel beams. With a working load limit of 1.5 tons at 0–20°, it is designed for contractors and rigging professionals who need a reliable vertical lifting solution without damaging protective coatings. The clamp attaches to beam flanges ranging from 3 in. to 7.25 in. wide and 0.25 in. to 0.5 in. thick, making it suited for a wide range of standard structural members. Manufactured by The Caldwell Group under the RENFROE brand in Beloit, WI, this clamp meets OSHA 1926 Subpart M, OSHA 1910.140, ANSI Z359.1, and ANSI A10.32-2012 requirements, qualifying it for use as part of a fall protection system as well as a lifting clamp.

Unlike standard beam clamps, the NMBC incorporates non-marring pads on the jaw contact surfaces, preventing scratching or coating damage on galvanized, painted, or otherwise finished beams. This makes it the preferred choice when surface integrity is a project requirement and standard steel-jaw clamps are not acceptable.

Key Features & Benefits

Non-Marring Jaw Pads

The clamp's jaw contact surfaces are fitted with non-marring pads that protect the coating and finish of coated beams during lifts. This eliminates touch-up work and protects the corrosion resistance of galvanized or painted structural members on the job site.

Locking Clamp Design

The Model NMBC uses a locking mechanism to secure the clamp to the beam flange prior to lifting. This positive-lock design prevents accidental release and is a requirement for safe lifting operations.

Dual-Use: Lifting and Fall Arrest

The NMBC meets OSHA 1926 Subpart M, OSHA 1910.140, ANSI Z359.1, and ANSI A10.32-2012 requirements, allowing it to serve as an anchor point in a personal fall arrest system in addition to its primary lifting function. This dual capability adds jobsite value for crews working at elevation.

Portable and Compact

At 9.5 lbs and with an overall footprint of 11.88 in. (L) × 5 in. (W) × 11.75 in. (H), the NMBC is light enough to carry and reposition by hand between lifts. Its portable design supports fast setup and breakdown on steel erection and structural work.

Wide Flange Compatibility

The clamp accommodates flange widths from 3 in. to 7.25 in. and flange thicknesses from 0.25 in. to 0.5 in., covering a broad range of structural steel sections. Contractors can use a single clamp across multiple beam sizes on the same project.

RENFROE Brand Reliability

The RENFROE brand has been trusted by lifting clamp users internationally for more than 50 years and is manufactured by The Caldwell Group. Rebuild kits are available separately, allowing worn components to be replaced affordably to maintain long clamp service life.

Common Applications

Lifting Coated or Galvanized Steel Beams

The non-marring pads make this clamp the correct choice when lifting painted, powder-coated, or galvanized structural beams where surface damage would require remediation or violate project specifications.

Structural Steel Erection

The NMBC can be used to position and lift standard structural steel beams during building frame erection where flange dimensions fall within the clamp's rated range.

Fall Arrest Anchor Point

Because the clamp meets OSHA and ANSI fall protection requirements, it can be used as a beam-mounted anchor point for a personal fall arrest system when workers are operating at height near structural steel.

Industrial Maintenance and Rigging

The portable design allows the NMBC to be quickly deployed in plant maintenance environments where overhead beams need to be rigged for equipment moves or structural work without permanent rigging infrastructure.

Compatible Materials

• Painted structural steel beams
• Galvanized steel beams
• Powder-coated steel beams
• Uncoated structural steel beams (flanges 3–7.25 in. wide, 0.25–0.5 in. thick)

Product Documents

• Download Catalog
• Download Manual
• Lifting Clamp Survey Report
• Lifting Tool Inventory and Maintenance Form
• Minimum Recommended Clamp Inspections
• Renfroe Repair Kits Catalog

Application Instructions

Before Use

1. Read and understand the full Operator's Manual before putting the clamp into service. Take the manual to your supervisor before first use.
2. Inspect the clamp before each lift per the inspection and maintenance instructions in the Operator's Manual.
3. Verify the beam flange width (3–7.25 in.) and thickness (0.25–0.5 in.) are within the clamp's rated range.
4. Confirm the load does not exceed the 1.5-ton working load limit at 0–20°. Use the correct capacity clamp for the load — do not use a larger-capacity clamp to lift light loads.
5. Use enough clamps to balance the load. Do not lift unbalanced loads.

Attachment

1. Position the clamp jaws over the beam flange.
2. Adjust the clamp to fit the flange using the adjusting screw.
3. Lock the clamp closed with the lock mechanism. Do not lift with the lock in the open position.
4. Connect a flexible connection between the crane hook and the clamp shackle. Do not attach the clamp directly to a crane hook or use a heavy flexible connection.

Lifting

1. Secure the load before attaching the clamp.
2. Do not lift over workers, safety areas, or personnel.
3. Do not side-load with a straight shackle clamp.
4. Do not alter, grind, weld, or modify the clamp in any manner.
5. Use only RENFROE replacement parts to ensure proper operation.

Technical Specifications

Frequently Asked Questions

Q: Can the NMBC-01.50-A be used as a fall arrest anchor point?
A: Yes. The Model NMBC meets OSHA 1926 Subpart M, OSHA 1910.140, ANSI Z359.1, and ANSI A10.32-2012 requirements for fall protection, qualifying it for use as part of a personal fall arrest system in addition to its lifting function.

Q: What flange sizes is this clamp compatible with?
A: The NMBC-01.50-A accepts beam flanges from 3 in. to 7.25 in. wide and 0.25 in. to 0.5 in. thick.

Q: Why choose the NMBC over a standard beam clamp?
A: The NMBC is specifically designed with non-marring jaw pads to protect the coating and finish of coated or galvanized beams. Standard beam clamps without these pads can scratch or damage protective coatings during lifting.

Q: Are replacement and rebuild parts available for the NMBC?
A: Yes. Caldwell offers RENFROE Rebuild Kits that allow you to replace wear parts affordably to extend the service life of the clamp. Only genuine RENFROE replacement parts should be used to ensure proper operation. See the Renfroe Repair Kits Catalog in the Product Documents section.

Q: Can the clamp be attached directly to a crane hook?
A: No. The Operator's Manual specifies that you must use a flexible connection between the crane hook and the clamp shackle. Do not attach the clamp directly to a crane hook or use a heavy flexible connection.