Starrett 53071 Small Hole Gage 0.2 to 0.3 Inch Full Ball

Product Description

The STARRETT 53071 is a small hole gage designed for precise internal measurement of bores, holes, and slots. It features a full ball contact style that allows the technician to expand the measuring element inside the opening and transfer the reading to an outside micrometer or caliper for an accurate diameter reading. With a measurement range of 0.2 to 0.3 inches and a 3 inch overall length, this gage suits tight, shallow holes where larger tools cannot reach. Machinists, tool and die technicians, and precision tradespeople rely on this type of gage for quality inspection and close-tolerance work.

This gage is suited for inspecting small drilled or reamed holes in metal components, checking valve guides, bushings, and similar bore features in maintenance and manufacturing environments. Its compact size makes it a practical addition to any precision measurement kit used in machine shop, maintenance, or field service applications where direct-reading bore gages are too large to fit the opening.

Key Features

• Measurement range of 0.2 to 0.3 inches for small bore applications
• Full ball contact style for consistent seating inside the measured opening
• 3 inch overall length provides clearance and control during transfer measurement
• Transfer-style measurement works with outside micrometers or calipers
• Compact form factor reaches shallow or tightly spaced holes

Compatibility

Designed as a standard small hole gage for use wherever transfer-style internal measurements in the 0.2 to 0.3 inch range are required. Pairs with any outside micrometer or caliper capable of reading in that range.

Installation Notes

Small hole gages require no installation in the traditional sense, but proper technique is critical for accurate results. Insert the ball end into the hole, expand the contact element with the knurled thimble until light drag is felt, then lock and withdraw before transferring to the reference measuring tool. Keep the contact surfaces clean and free of burrs or debris to avoid false readings. Handle with care to avoid dropping, which can damage the precision ball contact.