Dial Indicators

Dial indicators are precision measuring devices used in mechanical and industrial applications to accurately determine small linear displacements. These devices are crucial for assessing clearances, tolerance, and variation in machined parts.

A typical dial indicator comprises a plunger that contacts the workpiece, a dial face displaying the measurement, a pointer indicating the reading, a rotatable bezel for zeroing, and a stem for mounting. Unlike calipers and micrometers, which measure overall dimensions, dial indicators excel at measuring minute variations and deviations from a reference point.

Types of Dial Indicators

Dial indicators are classified into two main categories: mechanical (analogue) and digital. Both analogue and digital versions are readily available with measurement scales in either imperial (inches) or metric (millimetres) units, catering to diverse engineering standards and preferences.

Plunger Dial Indicators

A plunger dial indicator measures linear displacement by translating the movement of a contact point into a reading on the dial face. As the plunger moves, its motion is amplified through a system of gears and levers, resulting in a magnified and easily readable measurement on the dial. These indicators are commonly used for tasks such as checking runout, flatness, and parallelism.

Dial Test Indicators

A dial test indicator, also called a lever indicator, uses a pivoting contact point to measure surface variations and deviations. The movement of the contact point is transferred to the indicator hand via a lever system. Key components include a circular body, an indicating hand, a revolution counter, a graduated scale, and a spindle with the contact point. Dial test indicators are useful for tasks such as calibrating lathes and vices, aligning workpieces, and checking the trueness of rotating parts.

Digital Dial Indicators

Digital dial indicators offer several advantages over their mechanical counterparts. Their electronic displays provide clear, unambiguous readings, often with higher accuracy and resolution. They frequently include features such as data output capabilities for connecting to computers or data loggers, allowing for automated data collection and analysis. Digital indicators may also offer functions like preset values, tolerance settings, and the ability to switch between metric and imperial units.

Key Considerations When Choosing a Dial Indicator

Selecting the appropriate dial indicator for your application hinges on its specifications. These parameters directly influence the accuracy, suitability, and ease of use of the indicator for your specific measurement tasks. Consider the following specifications carefully:

• Resolution/Accuracy: This refers to the smallest unit of measurement the dial indicator can display and the overall accuracy of its readings. Understanding the required precision for your task is paramount. For applications demanding tight tolerances, a digital dial indicator often provides higher resolution and accuracy compared to an analogue dial gauge indicator.
• Measuring Range/Travel: The measuring range, or travel, indicates the total linear distance the plunger or contact point can move. It's crucial to select a dial indicator with a sufficient measuring range to accommodate the maximum displacement you anticipate measuring in your application.
• Mounting Type: Dial indicators come with various mounting options to ensure compatibility with different stands and fixtures. Common mounting types include shank diameters (such as 3/8" or 8mm), lug backs, and plain backs. Always verify the mounting type of the dial indicator to match your existing setup.
• Dial Face and Reading: The dial gauge face can feature either a balanced or a continuous reading scale. Balanced dials typically have zero in the centre, useful for comparative measurements, while continuous dials have a single scale from zero to the maximum reading. Additionally, consider whether you require metric (mm) or imperial (in) units and ensure the clarity of the markings on the dial indicators for sale.

Avoid Common Mistakes when Purchasing Dial Indicators

To ensure you select the most suitable dial indicators for your precision measurement tasks, be mindful of these common pitfalls during your purchase:

• Don't underestimate the required accuracy: Resist the temptation to opt for the cheapest dial gauge for sale if your application demands precise measurements. Inadequate resolution can lead to significant errors and costly rework.
• Don't ignore the mounting requirements: Carefully assess the compatibility of the dial indicator's mounting type with your existing stands or fixtures. Whether you require a specific shank diameter (e.g., 3/8", 8mm), a lug back, or a plain back, ensure a proper match.
• Don't overlook the measuring range: Thoroughly evaluate the maximum displacement you need to measure in your applications. Selecting a dial indicator with insufficient travel will render it unusable for its intended purpose.

Applications of Dial Indicators

Dial indicators are used by mechanical engineers and technicians across various industries:

• Mechanical Workshops: In general mechanical workshops, dial indicators are routinely used for tasks such as checking the runout of shafts, ensuring the flatness of surfaces, and verifying the parallelism of machine components. Their accuracy is essential for quality control and ensuring proper functionality of mechanical assemblies.
• Precision Machine Shops: In precision machine shops, where tight tolerances are paramount, dial indicators play a role in aligning workpieces on machine tools like lathes and milling machines. They are also used to verify the accuracy of machined surfaces and ensure compliance with stringent specifications.
• Lathe Workshops: Dial test indicators are particularly valuable in lathe workshops for precisely setting up workpieces in chucks or fixtures, ensuring concentricity and minimising vibration during machining operations. They are also used to check the accuracy of tool positioning and the trueness of machined parts.
• Discrete Manufacturing: In automated assembly lines and manufacturing processes, dial indicators, often in their digital form with data output capabilities, are integrated into quality control stations. They provide automated checks on component dimensions and assembly accuracy, contributing to efficient and high-quality production.
• Process Manufacturing: Within process manufacturing plants, dial indicators are utilised for monitoring the alignment and stability of rotating equipment such as pumps and compressors. They help detect excessive vibration or shaft runout, enabling proactive maintenance and preventing costly equipment failures.
• Energy & Utilities: In the energy and utilities sector, dial indicators are employed for inspecting and maintaining turbines, generators, and other critical power generation equipment. They ensure proper alignment and minimise wear and tear, contributing to the reliable operation of power infrastructure.
• Facilities & Intralogistics: For maintenance and repair within large facilities and intralogistics operations, dial indicators are used to check the alignment of conveyor systems, the levelness of platforms, and the proper functioning of various mechanical components, ensuring smooth and safe operation of material handling equipment.

Your Trusted Dial Indicators Supplier & Manufacturer

RS is a leading supplier and distributor of dial indicators in Australia. We offer a comprehensive selection of high-quality dial gauges, including both analogue and digital dial indicators, from renowned brands such as Facom, Mitutoyo, and RS PRO.

We also carry other testing tools, such as torque testers and thickness gauges, to ensure precise measurement in engineering applications. Order your dial indicators online today. For more details on our ordering process, delivery services, and delivery fees, please refer to our Delivery page.