GD & T Guide vs WS Drill Bits
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
GD & T Guide
This app provides a digital version of a pocket guide to Geometric Dimensioning and Tolerancing (GD&T). It explains GD&T symbols, their application on engineering drawings, and common inspection techniques. It also includes tools for converting measurements and calculating position tolerances.
- GD&T symbol descriptions
- Engineering drawing application
- Inspection techniques
- Reporting methods
- Measurement conversion tool
- Fastener formula calculator
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This is an App version of our best-selling printed pocket guide on Geometric Dimensioning and Tolerancing (GD&T). In its 77 pages, it will give a description of GD&T symbols and their use on engineering drawings. Common inspection techniques and reporting methods are also included in the descriptions. There is a conversion app for X, Y rectangular measurements to position tolerance zones. There is a fixed and floating fastener formula App to calculate position tolerances using the standard screw and drilled clearance holes. Available in both inch and mm.
WS Drill Bits
This application serves machinists, designers, and manufacturing personnel with essential drill bit calculations. It features a comprehensive drill size chart with decimal equivalents, a calculator for optimal speeds and feeds across various materials, and a tool for determining drill point depth based on angle.
- Drill size and decimal equivalent chart
- Fast vertical scrolling with color-coded values
- Sliding scale for quick list navigation
- Speeds and feeds calculator for various materials
- Drill point depth calculator
- Supports metric and inch measurements
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Workshop (WS) Drill Bits Is a full functioning Drill Bit Calculator simply designed for the Machinists Workshop, Designer's and Manufacturing Personel. Contains the following three functions: 1) A vertical scrolling Drill Size and Decimal Equivalent Chart. *From 0.1mm(0.00394 Inch) to 101.6mm(4.0 Inches) *Offers Fast Vertical Scrolling *Inch Fractions are highlighted in Blue *Metric Numbers are highlighted in Red *Gage/Letter Numbers are also listed *Inch Fractions values are also listed. *A sliding scale allows you to jump to any point on the list fast.(Separately for both mm and inch values) 2) Twist Drill Speeds and Feeds *Calculates recommended Drill Speeds and Feed Rates for various materials: *Option to enter in either Metric or Inch size Drills -Aluminium -Brass -Bronze -Cast Iron -Hastelloy -Inconel -Magnesium -Monel -High Nickel Steel -Free Cutting Steel -Mild Steel -Steel -Tool Steel -Forgings -Alloys -Heat Treated Steels -Stainless Steels -Titanium -Wood and Plastics 3) Drill Point Depth Calculator *Calculates the Drill Point Depth for various Drill Point Angles (60',82',90',118',120',135') *Option to enter in either Metric or Inch size Drills.
Screenshots
Verdict
The clearest difference is rating: WS Drill Bits at 5.0 against GD & T Guide's 3.0. WS Drill Bits also leads on in-app purchases (none vs 2) and iOS requirement (9.0 vs 11.0). GD & T Guide's advantage is update cadence (every 5 months vs every 16 months) and ratings volume (9 vs 2). On price, ads and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. GD & T Guide sells 2 one-off in-app purchases. WS Drill Bits asks for nothing beyond the download.
WS Drill Bits holds the better App Store score, 5.0 against 3.0. Both are backed by a comparable volume of ratings — 9 and 2 respectively.
GD & T Guide ships an update every 5 months, WS Drill Bits every 16 months. The most recent releases landed on October 14, 2026 and October 16, 2026 respectively.
| Parameter | GD & T Guide | WS Drill Bits |
|---|---|---|
| Price | Free | Free |
| Rating | 3.0 (9 ratings) | 5.0 (2 ratings) — better |
| Positive reviews | 20.0% of reviews | — |
| Number of ratings | 9 — better | 2 |
| Update frequency | Every 5 months — better | Every 16 months |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | Free — better |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 11.0 | 9.0 — better |
| Further details — not scored | ||
| Size | 55 MB | 57 MB |
| Age rating | 17+ | 4+ |
| Developer | GeoTol Inc. | Rein Rapp |
Customer experience
GD & T Guide
WS Drill Bits
In-app purchases
GD & T Guide
- Full Book$1.99
- Geometric Dimensioning and Tec$3.99
WS Drill Bits
No in-app purchases






