Tap & Drill: Tap Drill Chart

The tap drill chart machinists actually reach for, in your pocket. Pick a thread and the right drill appears at a size you can read from across the bench, with its decimal size and thread percentage. ONE TAP, THE RIGHT DRILL • 1/4-20 is a #7. M8 x 1.25 is 6.8 mm. Every common thread, answered instantly. • Number, letter, fractional and metric drills checked together, closest first. • Next size up and down, each with its thread percentage. THE WHOLE CHART • UNC and UNF from #0 to 1 inch, ISO metric coarse and fine from M1.6 to M30. • Search, quick picks or browse the full chart like the one on the shop wall. CUT AND FORM TAPS • Form taps need a larger hole. Switch with one tap. • Set your own thread percentage for hard or deep holes. CLEARANCE HOLES • Close, normal and free fit for the same fastener, from ISO 273 and published inch charts. IDENTIFY A THREAD • Measure a bolt with calipers and a pitch gauge and see which threads it can be. • Look-alikes like M8 and 5/16 are flagged, so you check the pitch before you tap. MORE • Find a drill by size: type 0.257 or 17/64 and get the drill. • Your drill set: every answer snaps to the drills you actually own. • Rigid tapping feed for your spindle speed. • Shows the formula behind every number, so you can check it. BUILT FOR THE SHOP • Works offline. No account. No ads. • Large, high-contrast numbers and big buttons for gloved hands. • The screen stays on while you work. FREE AND PRO Free: cut tap drills for the everyday coarse threads (UNC #4 to 1/2, metric M3 to M12), favorites and the drill finder. Pro, one purchase, no subscription: every thread, form taps, clearance holes, thread identification, your drill set, thread percentage and tapping feed. Shared with your family. Every number comes from published standards and charts. If a value is not in a verified table, the app says so instead of guessing. Questions or a thread you need: support@retroselfie.me