GEAROLL spark plug gap tool, Red, Feeler Gauge + Gloves, 32-blade 0.001"–0.040" for 10/12/14/16mm plugs

GEAROLL Spark Plug Gap Tool is a compact, red hand tool with a 32-blade steel feeler gauge designed to set accurate gaps on most 10mm, 12mm, 14mm and 16mm threaded spark plugs quickly and repeatably.

If you service small engines, motorcycles, ATVs, lawn equipment or cars with standard-length spark plugs, this kit gives you a dedicated way to measure and adjust the electrode gap without relying on bent wires or guessing. The tool pairs a threaded clamping body with a precision 65 manganese steel feeler gauge (0.001"–0.040" / 0.03mm–1.0mm) and includes gloves so you can work cleanly. It's made for non-preset-gap spark plugs and standard thread sizes, not long- or short-reach or 18mm-thread plugs.

How do I use the GEAROLL gap tool to set a spark plug gap?

Using the tool is straightforward: choose the correct feeler blade for your target gap, clamp the plug, turn the knob to bend the side electrode, then re-check with the blade until the feeler slides with a slight drag. Small reversals prevent over-bending and protect the electrode finish.

• Select the blade matching the desired gap thickness (0.001"–0.040").
• Insert the spark plug into the tool and tighten enough to hold it upright.
• Turn the adjustment knob to open the gap; test with the feeler gauge and back off slightly when finished.
• Rotate knob backward slightly to disengage to avoid coating wear, then remove the plug.

What spark plugs and engines are compatible with this tool?

This gapping tool fits most standard spark plugs with 10mm, 12mm, 14mm and 16mm threads—common on cars, motorcycles, scooters, generators and garden machines. It does not accommodate 18mm threads or long/short reach specialty plugs.

• Compatible: standard-length, non-preset gap 10/12/14/16mm plug threads.
• Not compatible: 18mm threaded plugs or long-reach/short-reach designs.
• Ideal for small engines, powersports, and many passenger vehicles with standard plugs.

Why choose a 32-blade feeler gauge and 65 manganese steel construction?

The included 32-blade feeler set covers a wide measurement range so you can match factory gap specs precisely. The 65 manganese steel blades are hardened and polished to resist wear and maintain accurate thicknesses over repeated use.

• Range: 0.001"–0.040" (0.03mm–1.0mm) for precise gap matching.
• Material: hardened 65 manganese steel for durability and stable thickness.
• Polished blades reduce burrs and give consistent feel against electrodes.

What care and adjustment tips help avoid damage while gapping?

To protect the electrode coating and ensure accurate measurement, never force the tool or rotate the screw so the clamp and electrode scrape together. Use a slight backward turn before checking the gap to prevent spring-back errors and always verify with the feeler blade.

• Always back the knob slightly before measuring to offset electrode rebound.
• Avoid direct scraping between clamp surfaces and plug coating to preserve performance.
• Repeat small adjustments rather than one large bend for better precision.

Kit contents: 1 x GEAROLL Spark Plug Gap Tool (red), 1 x 32-blade feeler gauge set, and 1 x pair of gloves—ready to use on the bench or in the field.

Who is this for? The GEAROLL Spark Plug Gap Tool is aimed at DIY mechanics, hobbyists, powersports riders, small-engine technicians and anyone who wants a reliable, portable way to set spark plug gaps to factory or tuned specifications. If you work on vehicles with standard threaded plugs and want a repeatable, accurate method without specialized shop equipment, this compact kit is a practical addition to your toolbox.