Free Printable Tap Drill Size Charts (PDF)
DataTemplates
FAQ
How do I know whether to use the metric or standard (inch) chart for a mixed-project toolkit?
Check the thread marking on your screws or bolts—if it has a number like 1/4-20 or 3/8-16, use the standard chart. For sizes labeled in millimeters (e.g., M6 or M10), the metric chart applies. Many templates include both systems side-by-side for quick comparison, which is helpful when working with imported hardware or dual-standard projects.
Can I use these charts for tapping aluminum or softer metals without adjusting the drill size?
These charts provide the standard drill sizes for clean threads in steel or hardened materials. For aluminum or softer metals, you may need to drill *slightly smaller* to avoid oversized holes that weaken the thread. Consult a machinist’s handbook for metal-specific adjustments, as tap drill sizes can vary by material hardness and tap design.
What’s the best way to organize these charts in a workshop where multiple people access them?
Laminate and mount the most frequently used charts (e.g., 10-32, M6, or NPT) near workstations, while keeping a full set in a three-ring binder or on a clipboard for portability. For digital access, save PDFs on a shared network drive or tablet with a note-taking app for marking personal preferences, like which chart is used most often for a specific project type.
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