How to Calibrate a Cap Torque Tester?

1. Introduction

In quality control, precision is non-negotiable. Yet many manufacturers struggle with low-cost torque testers that cannot be calibrated on-site. Once accuracy drifts, your entire quality system becomes compromised.

The NLY-20A Cap Torque Tester eliminates this vulnerability with its Dead Weight Calibration capability. This engineering breakthrough allows you to verify and adjust accuracy in your own facility using traceable standard weights and a precision lever arm—no specialized technician required.

2. Understanding the Calibration Setup

The calibration process leverages basic physics principles with a precision-engineered setup:

1. Strategic Placement: Position the NLY-20A at the edge of a stable, level workbench with the fixture extending beyond the edge.

2. Precision Lever Mounting: Secure the calibration lever (machined to ±0.01mm tolerance) horizontally in the center of the 4-Post Fixture, ensuring zero deflection.

3. Weight Suspension: Attach an F1-class standard weight to the lever's precise measurement point using the included hook system, allowing it to hang freely off the bench edge.

4. Force Application: The gravitational pull on the weight creates a mathematically predictable torque through the lever arm directly to the sensor.

3. The Science of Torque Calibration

Calibration relies on the fundamental torque equation:

T = F × L

Where:

• T (Torque): The target standard value (N·m)

• F (Force): Weight-induced force under gravity

• F = m × g

• where g = 9.8 m/s²

• L (Length): Precise lever arm length (measured from rotation center to weight application point)

Practical Example

Consider a precision calibration using:

• Mass: 1.000 kg (F1-class weight)

• Lever length: 0.200 m (precision-machined arm)

Calculated torque: T = 1 × 9.8 × 0.2 = 1.96 N·m

• Within specification: Display reads between 1.95-1.97 N·m (±0.5% tolerance)

• Out of specification: Display reads outside this range, requiring calibration adjustment

4. Step-by-Step Calibration Procedure

Step 1: Preparation

• Place the NLY-20A on a stable, level workbench in a temperature-controlled environment (23°C ±2°C).

• Power on and allow 15 minutes warm-up time for optimal sensor thermal stability.

• Ensure the area is free from vibration and air currents that could affect measurements.

Step 2: Lever Installation

• Insert the dedicated calibration lever horizontally through the center of the 4-Post Fixture.

• Tighten the clamping mechanism to 2.5 N·m (use torque wrench for precision).

• Verify the lever is perfectly horizontal using a precision level (critical for accuracy).

Step 3: System Zeroing

• The lever itself exerts a minor torque that must be neutralized.

• Tap Zero on the touchscreen to tare the system.

• Verify the display reads 0.000 N·m before proceeding.

Step 4: Standard Load Application

• Carefully suspend the F1-class standard weight on the hook at the precise measurement point.

• For directional calibration:

• Left-side suspension: Calibrates Counter-Clockwise (Removal) torque measurement

• Right-side suspension: Calibrates Clockwise (Application) torque measurement

• The NLY-20A's advanced sensor allows bi-directional calibration for complete accuracy.

Step 5: Verification & Precision Adjustment

• Verification Mode: Observe the displayed reading and compare to the calculated standard value.

• If deviation is within ±0.5% (Class 0.5 accuracy), no adjustment is required.

• Calibration Mode: If adjustment is necessary:

1. Access System Settings → Data Calibration (enter administrator password).

2. Input the exact weight value (to 0.001 kg) and precise lever length (to 0.001 m).

3. Tap Confirm to initiate the internal calibration algorithm.

4. The system will calculate and store new calibration coefficients.

5. Verify success with a second measurement using a different weight value.

Step 6: Documentation

• Record the calibration date, standard weights used, and before/after readings in your calibration log.

• Print a calibration certificate directly from the NLY-20A for your quality records.

• Schedule your next calibration verification based on usage frequency (recommended: quarterly verification, annual full calibration).