Spi 91-409-3 Feeler Gauge Parallel Leaf 0.65mm

Product Description

The SPI 91-409-3 is a single parallel-leaf feeler gauge used to measure clearances, gaps, and tolerances in mechanical assemblies. The leaf measures 0.65mm thick, 0.5 inches wide, and 12 inches long, providing enough reach for deep or confined inspection points. Constructed from high carbon steel, the blade resists flex and wear under repeated use. This gauge is a standard precision measurement tool used by HVAC technicians, machinists, and service professionals when setting valve clearances, checking spark plug gaps, or verifying component spacing during assembly or maintenance.

The 91-409-3 is suited for trade and industrial applications where accurate gap measurement is required. The parallel leaf style delivers consistent thickness from end to end, making it reliable for measurements throughout the full length of the blade. Common applications include checking clearances on motors, compressors, burner components, and other mechanical assemblies encountered in HVAC, refrigeration, and general mechanical service work.

Key Features

• Parallel leaf design provides uniform 0.65mm thickness along the full 12-inch blade length
• High carbon steel construction for durability and resistance to deformation
• 0.5-inch blade width accommodates a range of gap inspection scenarios
• 12-inch length allows access to deep or hard-to-reach measurement points
• Compact and lightweight at 0.04 pounds for easy carry in a tool pouch

Compatibility

Designed as a general-purpose parallel-leaf feeler gauge suitable for mechanical gap and clearance measurement across HVAC, refrigeration, and industrial service applications.

Installation Notes

Feeler gauges are hand-measurement tools and require no installation. Always power down and de-energize equipment before inserting a gauge blade near moving parts or electrical components. Insert the blade with light, consistent pressure — forcing a blade can cause bending and introduce measurement error. Clean blades after use and store properly to prevent corrosion and maintain calibration accuracy.