New Proto® Interchangeable Head Torque Wrenches

June 11, 2012

Choice of ratchet, open end, and box heads eases work in tight spaces.

Proto has rolled out nine new Interchangeable Head torque wrenches and 125 head attachments. The Interchangeable Head wrenches consist of three electronic, two micrometer, and four pre-set versions. They come in 1/4, 3/8, and 1/2 in. drives, with torque values from 25 in-lbs to 250 ft-lbs. The attachments include Ratcheting, Open-End, and Box heads, in metric and inch sizes. An easy to understand part-numbering system matches the correct torque wrench to the attachment.

The Interchangeable Head system addresses the fact that mechanical assemblies are becoming tighter and more compact in a many industries – from Aerospace to Wind Power. The new wrenches allow users to remove the ratchet head and replace it with an open end or box head, whose narrower profile can fit into tighter spaces.

The new Proto wrenches also keep workers productive by letting them change heads without having to re-calculate torque values. That’s because the box and open-end attachments have the same center-to-center distance as the ratchet heads that fit on the same wrench. Each attachment is also marked with a recommended maximum torque value, to prevent over-torquing of fasteners.

The new head attachments offer the same features and benefits as other  Proto wrenches. For example:

Open Ends are angled to 15º to help increase the total arc swing that a fastener can be turned by flipping the wrench over. This helps keep the wrench clear of obstructions.

Ratcheting heads combine a low profile with a 15° arc swing for working in tight spaces, as well as a reversing lever design for quick, one handed operation. The 24-tooth configuration fits 4, 6 and 12-point fasteners. The alloy steel drive gear is engineered for strength and durability.

Box heads feature the patented Proto® TorquePlus™ Design, a high performance design that engages the fastener flats, not the corners, and is countersunk on both sides, making it easier to get the wrench on the fastener. The 12-point Box end is indexed to 7.5º to help keep the shank clear of obstructions by allowing the user to flip the wrench over to continue turning the fastener.

The wrenches themselves also include the same qualities that users enjoy in other Proto torque wrenches. For instance the Electronic Interchangeable Head torque wrench includes a rotating head for easy viewing of LCD display. Three-way Red/Green/Yellow lights and an audible buzzer tell users when the target torque is approaching, met, or has been exceeded. Target torque zone is adjustable from 1% to 10% of targeted torque value.

All of the new wrenches meet or exceed applicable ASME B107.14M and/or ASME B107.28 specifications.

About Proto® Industrial Tools

Proto has been making durable, high-quality hand tools and storage for more than 100 years, having grown from a small machine shop to a worldwide manufacturer and supplier. Our tools are developed according to strict industrial standards, with features that let users work faster and easier, including enhanced shock absorption and reduced slip. We are exhaustive in our efforts to make safe tools and provide tool safety education. We support industries including petrochemical, aerospace, oil and gas, government and military, and general manufacturing. For more information call 800-800-TOOL, or visit