# Drill and Tap Tool - Thread Tapping & Through Hole

> Drill bit size calculator for thread tapping operations. (iPhone/iPad app by Chewy Applications.)

- Source: https://appshunter.io/ios/app/drill-and-tap-tool-thread-tapping-and-through-hole/id421763062 (this page in markdown: same URL + `.md`)
- Developer: [Chewy Applications](https://appshunter.io/developer/415417492)
- Category: Reference, Utilities
- Price: $1.99
- Rating: 4.30/5 from 30 App Store ratings · 41 written reviews indexed
- Age rating: 4+
- Requires: iOS 9.0 · 3 MB
- Languages: American English
- Released: 2011-03-14
- Data updated: 2026-09-01
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/drill-and-tap-tool-thread-tapping-and-through-hole/id421763062/reviews.md

## What is Drill and Tap Tool?

iOS 10 compatible!
Whether you use Metric taps and drills, US Standard taps and inch drills, or any combination of size types, this app has the answers.  No typing required; just tap your thread type and spin the dials to find the correct size of drill for your thread tapping operation.

The interface allows for selection of the following variables to calculate your required drill size:
• Thread Type,
• Tap Size, 
• Percentage Depth of Thread,
• Through Hole Clearance, 
• Cutting or Forming Operation
 
The closest drill bits are given in Metric, Fractional Inch, and US No. / Letter sizes, making this the perfect tool for those using a mix of tap and drill types.  

The app ensures complete control and accuracy of your operations by recalculating the actual percentage-depth-of-thread and through-hole clearance for each closest drill bit size.

Thread types include:
• US Standard UNC, UNF, UNEF
• ISO Metric coarse, fine
• National Pipe Thread - Tapered (NPT)
• National Pipe Thread - Straight (NPS/NPP)
• British Pipe Standard Thread - BSP (Parallel - G)
• British Pipe Standard Tapered Thread - BSPT (Parallel - R / Rp)

A helpful reference tool for engineers, machinists, trades-men, students, tool makers, DIYers, fitters and turners, and fabricators, etc.

## Key features

- Metric and US Standard tap/drill support
- Spinning dial interface for easy selection
- Calculates drill size for tapping
- Supports various thread types (UNC, UNF, NPT, BSP, etc.)
- Provides drill sizes in Metric, Inch, and US No./Letter
- Calculates percentage depth of thread
- Calculates through-hole clearance

## Recent user reviews (10 of 41)

All indexed reviews: https://appshunter.io/ios/app/drill-and-tap-tool-thread-tapping-and-through-hole/id421763062/reviews.md

### 5/5 — Very useful tool

*2025-08-09, version 4.0*

Used frequently & is easy to use

### 2/5 — Disappointed

*2025-03-12, version 4.0*

You should advise the sizes of the threads covered.
First time I used app found it did not cover the tapping size I was after 1 1/8” unf 
Maximum size covered is 1” unf

### 5/5 — Best drill and tap app!!!

*2025-03-05*

I’m a machinist and industrial mechanic and use this app on a daily basis, it’s so great to have all this info with me in my pocket at all times! Highly recommend this app!!!

### 4/5 — Stopped working, please fix!

*2024-02-12*

I’ve been using this app for several years, but it stopped working, please fix it.

### 3/5 — Great app won’t open

*2023-12-09*

App is great but will not open on any devices. PLEASE FIX

### 1/5 — Drill tap tool

*2023-10-24, version 4.0*

This app does not work would not recommend

### 5/5 — Good app, but will not start up

*2023-09-16*

Love this app, but since the update, it will not even open. please fix this problem because I love your app

### 1/5 — Needs up dating

*2023-05-14*

Was a great tool. 
Have iPhone 14 pro max, can’t use the app anymore. 
So sad!!!

### 4/5 — Stopped Working, please update!

*2023-03-20*

Love the app, please update!

### 5/5 — Handy app

*2023-02-05*

I use this app all the time, but all of a sudden it stopped working

## Frequently asked questions about Drill and Tap Tool

### What does the Drill and Tap Tool app do?

This app helps you determine the correct drill bit size needed for your thread tapping operations. It supports a wide range of thread types and measurement systems, ensuring accuracy for your projects.

### What types of threads does the app support?

The app supports numerous thread types including US Standard (UNC, UNF, UNEF), ISO Metric (coarse, fine), National Pipe Thread (NPT, NPS/NPP), and British Pipe Standard (BSP, BSPT).

### How do I find the right drill size?

Simply select your thread type, tap size, desired percentage depth of thread, and clearance requirements. The app will then display the closest drill bit sizes in Metric, Fractional Inch, and US No. / Letter formats.

### Is this app compatible with my device?

The app is compatible with iOS 10 and later versions. It is designed to run on iPhones and iPads.

### Who would benefit from using this app?

This app is a valuable tool for engineers, machinists, trades-men, students, tool makers, DIY enthusiasts, fitters, turners, and fabricators who need precise drill sizes for tapping.

## Version history (last 5 releases)

### 4.0 — 2017-05-11

This update from Apple will improve the functionality of this app. No new features are included.

- 64-bit compatibility added to allow app to function on future versions of iOS.
- Updated UI for devices with 4.7 inch, 5.5 inch screens.
- Fresh new app icon.

### 3.3.0 — 2013-10-31

• Updated the user interface to lighten the tap size picker for better text visibility.

### 3.2.0 — 2013-10-15

- Redesigned the user interface for iOS 7 (please let us know what you think of the new design via the 'Email Feedback' function in Settings). 
- 4-36 (No.4 - 36) thread added to UNC (US Standard) for Donnie.
- Moved the size picker upwards in the user interface for easier scrolling with your thumb.
- Changed the default 'Depth of Thread' to 75%. This affects new installations of the app only; existing users' defaults will remain unchanged with this update.
- Other minor enhancements.

### 3.1.0 — 2013-08-15

• UI updated for iPhone 5's larger display
• Added another pipe thread type (BSPT)

Thanks for all your feature requests! We're still working to add more for the next update. We look forward to more requests from you.

### 3.0.0 — 2012-12-03

- Added common pipe thread types (BSP, NPT, NPP)
- New clearer layout and graphics for main screen

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## More apps by Chewy Applications

- [Drill Size Charts - Drill bit size tables to show US Number / Letter and Fraction Inch sizes in Decimal Inch and Metric Conversions](https://appshunter.io/ios/app/drill-size-charts-drill-bit-size-tables-to-show-us-number-letter-and-fraction-inch-sizes-in-decimal-inch-and-metric-conversions/id418091864)
- [SpeedGlow Speedometer - Gesture Controlled Speedo](https://appshunter.io/ios/app/speedglow-speedometer-gesture-controlled-speedo/id523586069)
- [GST NZ Calculator](https://appshunter.io/ios/app/gst-nz-calculator/id587311220)
- [Australia GST - Tax Calculator](https://appshunter.io/ios/app/australia-gst-tax-calculator/id592595980)
- [Cooking Converter - Weights, Volumes, Temperatures](https://appshunter.io/ios/app/cooking-converter-weights-volumes-temperatures/id675494449)

All apps by Chewy Applications: https://appshunter.io/developer/415417492

## Related topics

[drill size charts](https://appshunter.io/ios/topics/drill-size-charts) · [drill chart](https://appshunter.io/ios/topics/drill-chart) · [drill bit converter](https://appshunter.io/ios/topics/drill-bit-converter)

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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 2026-09-01.*