# Tap & Drill: Tap Drill Chart — Thread Sizes for Machinists

> Thread Sizes for Machinists (iPhone/iPad app by Atanas Dimitrov.)

- Source: https://appshunter.io/ios/app/tap-and-drill-tap-drill-chart/id6820618415 (this page in markdown: same URL + `.md`)
- Developer: [Atanas Dimitrov](https://appshunter.io/developer/1847033891)
- Category: Reference, Utilities
- Price: Free
- Age rating: 17+
- Requires: iOS 16.4 · 56 MB
- Languages: American English
- Released: 2026-10-20
- Data updated: 2026-10-26

## What is Tap & Drill?

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

## Is Tap & Drill safe?

Not enough ratings yet to assess Tap & Drill.

## Is Tap & Drill legit?

Tap & Drill: Tap Drill Chart appears legitimate, with a few gaps. The AppsHunter Legitimacy Score for Tap & Drill is 65 out of 100 points across 7 verification signals from App Store and developer data.


## Version history (last 1 release)

### 1.0 — 2026-10-20

No release notes.

## More apps by Atanas Dimitrov

- [RetroSelfie: AI Photo Editor](https://appshunter.io/ios/app/retroselfie-ai-photo-editor/id6759565277)
- [Neon Ricochet](https://appshunter.io/ios/app/neon-ricochet/id6761478817)
- [Grid: Habit Tracker](https://appshunter.io/ios/app/grid-habit-tracker/id6795602308)
- [ShiftDeck: Shift Work Calendar](https://appshunter.io/ios/app/shiftdeck-shift-work-calendar/id6820088553)

All apps by Atanas Dimitrov: https://appshunter.io/developer/1847033891

## Related topics

[tap drill](https://appshunter.io/ios/topics/tap-drill)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-10-26.*