Precision Bolt Tensioning with DTI Washers

DTI washers—short for Direct Tension Indicator washers—are the industry standard for verifying bolt tension in structural steel connections. Also known as load indicating washers or tension indicating washers, these engineered fasteners compress under load, ensuring that your bolts achieve the correct clamping force.

At Portland Bolt, we stock and supply both standard DTI washers and Squirter™ DTIs, manufactured by Applied Bolting Technology in compliance with ASTM F959/F959M. Whether your project requires imperial ASTM A325, A490, or metric 8.8,10.9, our DTIs offer a simple, accurate, and cost-effective solution for tension verification.

Why Choose DTI Washers?

• Direct verification of bolt tension – eliminates uncertainty from torque-only methods.
• Faster, more reliable installation – washer compression provides instant, visible feedback.
• Improved safety & performance – ensures proper preload, reducing risk of connection failure.
• from 1/2″ through 1-1/2″ diameters and M12 through M36

Squirter™ DTI Washers

Applied Bolting Technology’s Squirter™ DTIs make installation even easier. As the washer compresses, colored silicone is released, creating a visible “squirt” that confirms correct bolt tension. This innovation streamlines inspections, minimizes errors, and ensures adherence to project specifications.

Specifications

• Diameter Range Imperial: 1/2″ – 1-1/2″
• Diameter Range Metric: M12 – M36 8.8 & 10.9
• Finishes: Plain or Mechanical Galvanized (A325 & 8.8), Thermally Diffused Zinc (A490 & 10.9)
• Manufacturing: Domestic production with full certifications
• Standard: ASTM F959/F959M

Stock

• Diameters: 1/2″ – 1-1/2″
• Origin: Domestic
• Finish: Plain and mechanically galvanized
• Item: Load indicating washers for A325 only