Spi 91-376-4 Feeler Gage 0.023 in Parallel Leaf Steel

Product Description

The SPI 91-376-4 is a parallel-leaf feeler gage used to measure precise gaps, clearances, and tolerances in mechanical assemblies. The leaf measures 0.023 inches thick, 0.5 inches wide, and 12 inches long, providing consistent cross-section along the full length for accurate readings at any contact point. Constructed from high carbon steel, the blade resists wear and holds its calibrated thickness through repeated use. This type of gage is a standard hand tool in HVAC, mechanical, and industrial service work where precise clearance measurement is required during equipment setup, adjustment, or inspection.

This feeler gage is suited for residential and commercial applications where technicians need to verify spark plug gaps, valve clearances, bearing fits, or component spacing. The 12-inch parallel leaf length accommodates deep or extended measurement reach that shorter blades cannot achieve. HVAC technicians commonly use feeler gages during burner and blower assembly checks, while general mechanical trades rely on them for motor and equipment alignment tasks.

Key Features

• 0.023-inch calibrated thickness for precise gap and clearance measurement
• Parallel leaf style maintains uniform width of 0.5 inches across the full 12-inch length
• High carbon steel construction for durability and dimensional stability
• Full 12-inch leaf length provides extended reach in confined or deep assemblies
• Single-leaf format for straightforward, unambiguous measurement tasks

Compatibility

Designed as a general-purpose parallel-leaf feeler gage suitable for use in any application requiring a 0.023-inch gap measurement standard across HVAC, plumbing, electrical, and general mechanical service work.

Installation Notes

Feeler gages are installed and removed by hand — no special tools are required. Always clean contact surfaces before inserting the leaf to prevent false readings caused by debris or corrosion. Do not force the blade into a gap narrower than its rated thickness, as this can permanently deform the leaf and compromise calibration. Store the gage flat or in a protective sleeve to maintain its precision thickness over time.