Fowler

The Fowler collection carries nine products across four instrument categories: bore gages and hole micrometers (XTH3 Holematic Pistol Grip Sets, Electronic Holemike Set, and XTA Holemike), electronic indicators (Mark VI and QuadraTest series), probe accessory sets, and an 8mm probe set. Together they cover internal bore measurement, surface and runout measurement, alignment, flatness checking, and comparative measurement forming a well-rounded precision measurement toolkit for machinists, quality engineers, and fabricators. Fowler has been delivering metrology solutions for more than 75 years.

A bore gage is a precision instrument specifically designed to measure the internal diameter of bores, holes, and cylinders. While an outside micrometer measures external dimensions in a straightforward linear contact, measuring the inside of a bore accurately requires a self-centering, three-point contact system that finds the true diameter regardless of the probe angle. Fowler's Holematic and Holemike instruments use three-point carbide contacts that automatically center themselves in the bore, producing reliable, repeatable readings that a two-point instrument or caliper cannot match especially in deep, blind, or small-diameter bores where correct alignment is difficult to achieve manually.

Both are three-point electronic bore gaging systems with Bluetooth, but they serve different bore size ranges and ergonomic needs. The XTH3 Holematic Pistol Grip Sets are designed for smaller bores, the 54-567-020-BT covers 0.375"–0.750" (10–20mm) and the 54-567-620-BT extends the range to 0.250"–0.750" (6–20mm) using an ergonomic pistol grip handle that gives the operator better control and reduces fatigue in high-repetition inspection tasks. The Electronic Holemike (54-367-050-BT) covers a larger range of 0.750"–2.000" (20–50mm) with a traditional extension handle configuration, making it better suited for mid-size bores in machined parts, castings, and housings. Resolution is 0.00005"/0.001mm across all three, with the Holemike specifying ±0.0001" accuracy.

The Fowler-Bowers XTA Series Holemike (52-255-318-0) is a precision mechanical bore micrometer covering 2.000"–2.625" it does not have a digital display or Bluetooth. This makes it the right choice when electronic output is not required, when the environment is hostile to electronic components (excess coolant, vibration, or high EMI), or when a durable, battery-free instrument is preferred for a specific bore size range that falls outside the electronic models. The XTA Series is a proven mechanical design trusted in machining and inspection environments for its simplicity and long-term reliability.

The Fowler Mark VI Electronic Indicator is a high-precision electronic dial indicator offering a 0–1" (25mm) measuring range and Bluetooth wireless data output. The 54-530-355-0 model includes Bluetooth for wireless SPC data transfer, while the 54-530-156-0 features an 8mm mounting stem and comes with a Fowler lifetime warranty. Both are designed for comparative surface measurement, part-to-part variation checks, runout inspection, flatness verification, and machine tool setup for anywhere a repeatable, digital reading of small linear displacements is needed. They mount to standard indicator holders and magnetic bases and are equally at home in a quality lab or on a production floor.

The QuadraTest (54-562-890-BT) is a lever-style electronic test indicator distinct from a plunger-type dial indicator in that its contact point pivots on an arm rather than moving linearly. This makes it ideal for reaching into tight spaces, measuring in confined bores, checking runout on shaft shoulders, and performing alignment tasks where a plunger indicator cannot be positioned. The "multimode" designation indicates it supports multiple measurement functions, while Bluetooth output enables wireless transmission of readings to Fowler Data-Xchange software or compatible SPC platforms without tethering the instrument to a cable. Its digital display provides cleaner, faster readings than analog dial test indicators.

All Bluetooth-enabled products in this collection transmit wirelessly to compatible devices and SPC software platforms. Fowler's own Data-Xchange software is the primary supported application, allowing measurements from multiple Bluetooth instruments to be captured, logged, and analyzed in real time on a PC, tablet, or mobile device. This eliminates manual data entry errors and the cabling that creates trip hazards and workflow interruptions on busy production floors. Standard Bluetooth connectivity also makes these instruments compatible with many third-party SPC and quality management platforms that accept wireless gauge inputs.

Two probe accessory sets are available in the collection. The Fowler 54-930-217-0 Basic Probe Accessory Set is a versatile expansion kit designed to extend the reach and capability of compatible Fowler electronic indicators adding contact points, extensions, and probe tips for measuring in a wider variety of part geometries and configurations. The 54-199-106-0 8mm Probe Set is a precision accessory kit specifically designed for Fowler electronic indicators with an 8mm stem (such as the 54-530-156-0 Mark VI), providing calibrated probe tips for specialized inspection tasks. Both sets ship with protective storage cases and documentation.

Fowler instruments are workhorses of the manufacturing and quality control environment. The bore gages and hole micrometers are trusted in precision machining shops inspecting bored housings, engine components, hydraulic cylinders, bearing bores, and transmission components. The electronic indicators are standard equipment in quality labs, surface plate inspection stations, and CMM setups. The test indicator finds frequent use in machine tool alignment, fixture verification, and in-process runout checking on CNC lathes and machining centers. Across the collection, Bluetooth capability makes every instrument well-suited for paperless, SPC-integrated inspection workflows in aerospace, automotive, medical device manufacturing, and general precision machining.

All Fowler products ship free to the continental USA, backed by a best-price guarantee. A 30-day return policy and Affirm financing at checkout are available. The 54-530-156-0 Mark VI also comes with Fowler's lifetime warranty, providing long-term protection on the instrument itself. Government and institutional buyers can submit an RFQ through the dedicated Government RFQ page. For guidance on selecting the right bore gage range, indicator type, or probe set for a specific application, call or text Gustavo directly at 617-398-7852, Monday through Friday, 8am–5pm EST.