Toolwiz Spark Plug Gap Tool — 32-Blade Black feeler gauge, fits 10–16mm plugs, hardened-steel precision

Toolwiz Spark Plug Gap Tool is a handheld gapper that safely and precisely reduces spark plug electrode gaps using a 32-blade steel feeler gauge and an adjustable compression knob.

This compact tool gives DIY mechanics and professional technicians a controlled way to set spark plug gaps on most common 10mm–16mm plugs. Built with a hardened steel feeler gauge and a sturdy black-finished body, it streamlines gap reduction tasks and helps you achieve repeatable results without bending electrodes by hand.

How does this tool make spark plug gap adjustment easier?

The Toolwiz gapper holds the plug securely while a turning knob compresses the electrode to the target gap, avoiding direct bending that risks damage. The included 32-blade feeler gauge provides precise reference sizes so you can dial in the gap quickly.

• Simple place-and-turn operation for controlled compression
• Reduces gap only — prevents accidental over-expansion
• 32-blade gauge covers 0.001"–0.040" (0.03–1.0mm) for fine increments

Which spark plugs will this Toolwiz gapper work with?

It fits most standard spark plugs with 10mm, 12mm, 14mm, and 16mm thread diameters. It is not suitable for 18mm threads or plugs that require long- or short-reach tools, and it’s not intended to adjust preset-gap Iridium or Platinum plugs in most cases.

• Compatible: standard 10mm–16mm thread spark plugs
• Not compatible: 18mm thread, long-reach, or short-reach plugs
• Recommended: use on non-preset-gap plugs only

What accuracy can I expect when setting gaps with this kit?

The hardened 65 manganese steel feeler gauge is dual-marked and polished for consistent thickness across blades, supporting repeatable gap settings. Because electrode metal can spring back slightly, the tool’s controlled compression plus a slightly smaller gauge blade will help you reach the intended value reliably.

• Gauge range: 0.001"–0.040" (0.03–1.0mm) in 32 blades
• Material: hardened, polished 65 manganese steel for durability
• Tip: use a marginally smaller blade than target to offset spring-back

How do I use the Toolwiz Spark Plug Gap Tool safely and effectively?

Seat the spark plug into the tool, select the appropriate feeler blade, then slowly turn the knob until the electrode compresses to the feeler thickness. Inspect the electrode visually and recheck with the gauge; remember this tool only reduces gaps, so take incremental adjustments.

• Step 1: Insert plug and pick correct feeler blade
• Step 2: Turn knob slowly until electrode contacts the blade
• Step 3: Recheck gap and repeat if necessary; do not force

Who is this for? The Toolwiz Spark Plug Gap Tool and 32-blade feeler gauge suit home mechanics, small engine technicians, and anyone who services spark plugs and needs a compact, repeatable way to reduce electrode gaps. It’s ideal for routine tune-ups, classic vehicles, motorcycles, lawn equipment, and other machines using standard 10mm–16mm spark plugs where careful gap control matters.