Caldwell Model RSC Locking Type Vertical Lifting Screw Clamp

Renfroe Model RSC-00.50-B Locking Screw Type Vertical Lifting Clamp — Reliable Bench Work on Thick Steel Plate

The Renfroe Model RSC-00.50-B is a locking, screw-type vertical lifting clamp rated at 0.5 tons (1,000 lbs), engineered specifically for bench work on steel plates of large thickness weighing less than 1,000 lbs. Manufactured by The Caldwell Group, Inc. in Rockford, IL, this clamp is part of the trusted RENFROE brand — preferred by international lifting clamp users for more than 50 years. It accommodates plate thicknesses from 1-3/8 in. up to 4-1/4 in. and is designed for vertical and 180° lifting operations. This clamp is sold through a worldwide network of stocking distributors and is built to the same high-quality performance standards the RENFROE brand is known for.

Compared to standard vertical lifting clamps, the Model RSC features a lightweight screw-type locking mechanism that makes it easier to handle in bench work environments — particularly when working with large-thickness plate that demands a secure, positive grip. Its locking design provides an added layer of security that passive-grip clamps cannot offer, reducing the risk of accidental release during positioning or lifting operations.

Key Features & Benefits

Locking Screw Mechanism

The RSC uses a screw-type jaw that positively locks onto the plate, providing a secure, controlled grip. This locking action is critical when working with heavy steel plate where an unsecured clamp could result in a dropped load or injury.

Lightweight Construction for Easier Handling

At 16.5 lbs, the RSC-00.50-B is designed to be lightweight and easier to handle for capacities up to 1/2-ton. This reduces operator fatigue during repetitive bench work positioning tasks.

Wide Jaw Opening — Up to 4-1/4 Inches

The RSC-00.50-B accepts plate thicknesses from 1-3/8 in. up to 4-1/4 in., making it well suited for large-thickness steel plate applications where narrower-opening clamps cannot be used.

Vertical / 180° Lifting Capability

This clamp is designed for vertical lifting and can operate through a 180° arc, providing flexibility when repositioning or turning plate during bench work operations. It must only be used in the vertical orientation — horizontal lifting with this clamp is not permitted.

Swivel Jaw and Shackle Assembly

The Model RSC includes a swivel jaw kit and shackle assembly as replaceable components, allowing worn or damaged parts to be serviced without replacing the entire clamp body. Using only genuine RENFROE replacement parts ensures proper operation and maintains load integrity.

Common Applications

Bench Work on Thick Steel Plate

The Model RSC is specifically designed for bench work on steel plates of large thickness weighing less than 1,000 lbs, where a secure locking grip is needed for controlled positioning.

Vertical Lifting of Single Steel Plates

This clamp is intended for lifting a single plate in a vertical orientation, where the lifting force is directly above and in line with the lifting shackle. Only one plate at a time should be lifted with a vertical clamp.

Plate Turning Through 180° Arc

The RSC's 180° lifting capability allows operators to turn a single plate from one horizontal position, through vertical, and back to horizontal — useful when repositioning plate during fabrication or staging operations.

Compatible Materials

• Steel plate (large thickness)
• Steel plate weighing less than 1,000 lbs
• Plate thickness range: 1-3/8 in. to 4-1/4 in. (RSC-00.50-B)

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 operator manual thoroughly before putting the clamp into service.
2. Inspect the clamp before each lift per the pre-lift inspection instructions in the operator manual.
3. Verify the plate weight is less than 1,000 lbs and within the 0.5-ton rated capacity of the clamp.
4. Confirm the plate thickness is within the jaw range of 1-3/8 in. to 4-1/4 in.
5. Use the correct clamp for the job — do not use large-capacity clamps to lift light loads.

Attachment

1. Secure the load before attaching the clamp.
2. Attach the clamp to the edge of the plate in the vertical orientation only.
3. Lock the clamp closed with the locking mechanism — do not lift with the lock in the open position.
4. 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.
5. Do not use a connection that may release the clamp.

Lifting

1. Lift only one plate at a time — do not lift more than one plate at a time with a vertical clamp.
2. Do not lift plate horizontally with this vertical lift clamp.
3. Do not lift over workers, safety areas, or personnel.
4. Use enough clamps to balance the load — do not lift loads that are not balanced.
5. Do not rush during lifting operations.

Prohibited Actions

1. Do not side load with this clamp.
2. Do not lift a plate from the bottom of a plate stack.
3. Do not alter, grind, weld, or modify the clamp in any manner.
4. Do not overload the clamp beyond its rated capacity.
5. Use only genuine RENFROE replacement parts to ensure proper operation.

Technical Specifications

Frequently Asked Questions

Q: What plate thickness range does the RSC-00.50-B accommodate?
A: The RSC-00.50-B accommodates plate thicknesses from 1-3/8 in. up to 4-1/4 in. If you need a clamp for thinner plate (0 to 3 in.), the RSC-00.50-A is the appropriate model.

Q: Can this clamp be used to lift plate horizontally?
A: No. The Model RSC is a vertical lift clamp only. Do not lift plate horizontally with this clamp.

Q: Can I lift more than one plate at a time with this clamp?
A: No. Do not lift more than one plate at a time with a vertical clamp. Lifting from the bottom of a plate stack is also prohibited.

Q: Can the clamp be modified or repaired with aftermarket parts?
A: The clamp must not be altered, ground, welded, or modified in any manner. Only genuine RENFROE replacement parts should be used to ensure proper operation and maintain load integrity.

Q: What replacement parts are available for the Model RSC?
A: The Model RSC has a full set of serviceable components including: Shackle Assembly (RSC-1), Handle Assembly (RSC-2), Screw (RSC-3), Screw Cup Kit (RSC-4), Swivel Jaw Kit (RSC-5), Spring – Screw Cup (RSC-6), and Spring – Swivel Jaw (RSC-7). Refer to the Renfroe Repair Kits Catalog for details.

Q: Should the clamp be attached directly to a crane hook?
A: No. Always use a flexible connection between the crane hook and the clamp shackle. Do not attach the clamp directly to a crane hook, and do not use a heavy flexible connection.