ThreadChaser
Screw Thread Identifier
Free · In‑App Purchases · Designed for iPad. Not verified for macOS.
Internal / External Thread Identifier
ThreadChaser is the fastest way to identify an unknown thread — on the shop floor, in the field, or at the workbench.
Simply measure the major diameter and pitch of any fastener or threaded component, enter the values, and ThreadChaser instantly searches its database of metric and imperial thread standards to find the closest matches. No more guessing, no more flicking through reference books, no more ordering the wrong tap or die.
Who it's for
ThreadChaser is built for engineers, machinists, mechanics, maintenance technicians, and anyone who regularly works with threaded fasteners. Whether you're identifying a mystery bolt on a piece of imported machinery, matching a thread on a worn component, or specifying a tap drill size for a new hole, ThreadChaser gives you the answer in seconds.
What it covers:
ISO Metric coarse and fine threads (M1 through M68)
Unified National threads — UNC, UNF, and UNEF
British Standard — BSW, BSF, and BSP
With more standards being added regularly
What you get:
Instant thread matching with a tolerance you control
Pitch diameter and minor diameter for every result
Recommended tapping drill sizes
Internal and external thread modes
Technical thread profile diagrams
A full reference library of thread standards and formulas
How to use:
Use a digital calliper to measure the major diameter or internal bore of the thread. Use a thread pitch gauge or ruler to measure the pitch (distance between thread crests). Enter both values, select your preferred standards, and hit Search. ThreadChaser ranks every match by how closely it fits your measurement.
Terms of Use:
https://www.threadchaser.com/TERMS
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
Fixed a bug that stops thread diagrams rendering in Dark Mode
The developer, JAMIE SAM PARTOVI, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- JAMIE SAM PARTOVI
- Size
- 1.6 MB
- Category
- Utilities
- Compatibility
Requires iOS 18.6 or later.
- iPhone
Requires iOS 18.6 or later. - iPad
Requires iPadOS 18.6 or later. - Mac
Requires macOS 15.6 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 2.6 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- ThreadChaser Pro $2.99
- Copyright
- © 2026 Jamie Partovi

