Starrett Engine Crankshaft End Play Gauge

When an engine is being assembled or diagnosed, the crankshaft is one of the first components to be verified. Starrett has long been a name in this part of the toolbox, and its crankshaft gauging offering reflects the same precision-instrument heritage that the company built after its founding in Athol, Massachusetts in 1880. This page focuses on Starrett's gauges for checking crankshaft condition and clearances; for the company's wider story, visit the Starrett brand page.

The Starrett Crankshaft Gauge Approach

Starrett's best-known crankshaft instrument is the 696-series Crankshaft Distortion Dial/Strain Gage. It is an inside-measuring dial gage designed to check the distortion of crankshaft webs, which relates directly to bearing misalignment or excessive bearing wear. It is meant to be used between the crank throws, where its pointed rods wedge in place, and as the shaft is rotated the dial shows whether the crank is flexing out of true.

A major selling point is that this check can be performed without tearing the engine down. The gage is intended for checking bearing alignment or shaft deflection without dismantling the engine, and it can also serve as a strain gage on engine frames.

Key Features of the 696 Series

• Wide working range: The 696Z covers 2-3/8 in. to 18 in. using ten rods and one extension, while the metric 696MZ covers 61 to 458 mm.
• Easy-to-read dial: The inch version has .001 in. graduations with a 0-20-0 dial, and the metric version has .02 mm graduations with a 0-50-0 dial.
• Practical indicator details: The dial has a movable bezel for zeroing and a non-breakable crystal, and the rods are marked to show the approximate overall length of the gage.
• Balancing attachment: The 696Z includes a balancing attachment, which is also available separately as the 696B.

Where It Fits in Crankshaft Checks

Crankshaft end play, or thrust clearance, is the axial clearance between the crank's thrust surface and the main thrust bearing. It is commonly measured with a magnetic-base dial indicator reading off the crank snout while the crank is gently pried fore and aft. Distortion and alignment checks answer a different but closely related question: whether the crankshaft and its main bearings are sitting true. Used together, these measurements give a fuller picture of the rotating assembly's health, whether for a diesel, a compressor, or a large stationary or marine engine, where the 696 series is especially well suited.

Why Precision Matters Here

Clearances measured in thousandths of an inch decide whether a crank turns freely for years or wears bearings prematurely. A gauge with reliable graduations and repeatable readings lets a builder or technician trust what the dial says. Starrett's reputation rests on exactly that kind of dependable, repeatable measurement, and its instruments are widely found in machine shops and engine rooms.

To compare other tools used for checking clearances and alignment, browse the full Engine Crankshaft End Play Gauge category, which covers the wider range of gauges and indicators available for this job.