# Drill and Tap Tool - Thread Tapping & Through Hole

> Reference

Canonical page: [https://chrome-stats.com/d/id421763062](https://chrome-stats.com/d/id421763062)

## Overview

- **ID:** `id421763062`
- **Platform:** Apple
- **Type:** Apple app
- **Status:** Available
- **Publisher:** Chewy Applications
- **Category:** Reference
- **Rating:** 4.30 / 5 (30 ratings)
- **Version:** 4.0
- **Last updated:** 2017-05-11
- **First published:** 2011-03-14
- **Size:** 2.59 MB
- **Data as of:** 2026-09-24
- **Store listing:** [Apple App Store](https://apps.apple.com/us/app/drill-and-tap-tool-thread-tapping-through-hole/id421763062)
- **Website:** [http://chewyapplications.com](http://chewyapplications.com/)

## Description

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.

## Rankings

- #218,154 — Overall

## Review summary

Users praise Drill and Tap Tool as a handy, accurate, must-have reference that saves time and supports handy conversions. They cite strong calculation features, material-specific adjustments, and good developer support. Recurrent downsides are stability/launch issues on newer devices, gaps in data (clearance hole sizes and certain thread standards), and some usability requests (direct drill-size output and better UI readability).

### Pros

- Pocket-sized, comprehensive reference for drilling and tapping; used daily and saves time.
- Accurate and versatile for calculating drill sizes, thread depths, and material-specific adjustments; supports what-if scenarios and conversions.
- Helpful for conversions (cut taps to form taps) and for correlating English and metric sizes.
- Useful for planning and troubleshooting; helps verify hole sizes and thread engagement.
- Responsive developer support with quick fixes and updates that improve usability.

### Cons

- Frequent crashes or launch failures; the app won't open on devices and has compatibility issues with newer iPhone models.
- Content gaps include missing clearance hole dimensions and incomplete coverage of thread sizes (e.g., NPT, BA, Heli-coil, pipe sizes).
- Early UI readability issues (color contrast on selector wheel) reported, though improved in updates.
- Some users want direct drill-size outputs instead of relying on adjusting the thread depth percentage.

## Similar extensions and apps

- [Tap & Drill Size Reference](https://chrome-stats.com/d/id6761641150)
- [Tap & Drill Pro](https://chrome-stats.com/d/id6764534603)
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- [Thread Calculators](https://chrome-stats.com/d/id1670586227) — 5.00 / 5
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- [Drill Size Charts - Drill bit size tables to show US Number / Letter and Fraction Inch sizes in Decimal Inch and Metric Conversions](https://chrome-stats.com/d/id418091864) — 4.50 / 5
- [Thread Calculator](https://chrome-stats.com/d/id1559560290) — 4.40 / 5
- [OSG Calculator](https://chrome-stats.com/d/id606137246) — 4.00 / 5
- [ThreadKing](https://chrome-stats.com/d/id1073753793) — 4.70 / 5
- [Screw Pitch Gauge](https://chrome-stats.com/d/id6749295527)
- [Drill Calc](https://chrome-stats.com/d/id304434324) — 4.10 / 5
- [Thread Gauge](https://chrome-stats.com/d/id6781018381) — 5.00 / 5

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Source: [Chrome-Stats](https://chrome-stats.com/d/id421763062)