Toolwiz Spark Plug Gap Tool with 32-Blade Feeler Gauge — Black, 10–16mm Fit, Precision Adjustment

The Toolwiz Spark Plug Gap Tool is a compact hand-held pincer that quickly and accurately compresses spark plug electrodes to set repeatable gaps, bundled with a 32-blade steel feeler gauge.

If you tune or maintain gasoline engines, consistent spark plug gaps are essential for reliable starts and steady performance. This Toolwiz kit gives you a purpose-built gapping plier plus a precision feeler gauge so you can adjust most common 10mm–16mm spark plugs without guessing. The tool is built to reduce the electrode gap only, and the included multi-blade gauge delivers fine measurement steps for repeatable results.

Which spark plugs can I use this gapping tool with?

The Toolwiz gapping tool works with a wide range of standard hex-thread spark plugs in 10mm, 12mm, 14mm, and 16mm sizes. It is not designed for 18mm-thread plugs or special long-reach and short-reach designs, and it won’t safely change preset gaps on many iridium or platinum plugs that are not meant to be adjusted.

• Compatible: most standard 10mm–16mm threaded plugs
• Not compatible: 18mm thread or unusual reach plugs
• Iridium/Platinum: usually left at factory gap unless manufacturer allows adjustment
• Function: reduces/closers gap only, cannot increase gap

How do I use the Toolwiz plug gapper for consistent results?

Set the plug into the jaws, select the closest feeler blade slightly under your target dimension, and squeeze the knurled knob until the electrode compresses to the gauge's thickness. Because some electrodes spring back, choosing a blade a hair smaller than the final gap helps achieve the intended measurement after release.

• Insert plug into tool jaws so electrode rests against bending post
• Select a feeler blade (e.g., 0.028" for a 0.030" target)
• Slowly rotate the adjustment knob until the electrode contacts the blade
• Release and re-check gap with the gauge to confirm final size

What precision and materials does the included feeler gauge provide?

The kit’s 32-blade feeler gauge covers metric and imperial markings from 0.001" to 0.040" (0.03–1.0mm), giving fine increments for accurate setup. Each blade is stamped on both sides and made from hardened 65 manganese steel that’s polished for longevity and consistent thickness.

• Range: 0.001"–0.040" (0.03–1.0mm) in 32 steps
• Material: hardened, polished 65 manganese steel for stable measurements
• Markings: dual-marked blades for easy imperial/metric reference
• Durability: corrosion-resistant finish and hardened edges for repeat use

Who this is for: The Toolwiz Spark Plug Gap Tool is suited to DIY mechanics, home tuners, motorcycle and small-engine owners, and professional technicians who need a compact, repeatable method to close spark plug gaps. If you frequently replace or inspect plugs and want a quick, durable tool with a precise feeler set, this kit provides the essential parts in one lightweight package. Note: if your spark plugs explicitly state “do not adjust,” follow the manufacturer’s guidance and do not attempt to alter those electrodes.