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Bolt & Nut

By Ryan Newsome

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Ever have difficulty determining what size wrench you need for that nut? Not sure if it is measured using the metric system or SAE? Wonder what the name of the type of head is on your bolts? We've got you covered!

'Bolt & Nut' is the must have tool for the mechanic, machinist, handyman or the average Joe with a wrench! Designed to allow a user to quickly determine the wrench size needed for a bolt or nut by using an onscreen full scale image of a nut.
* Slide your finger up or down on the screen to change the nut's size.
* Press the measurement standard button in order to toggle SAE to Metric and back again.
* A threading guide to determine the threads per inch or thread pitch.
* Handy reference guide for determining screw drive, head, and bolt marking with a quick description for each item.
* A scrolling ruler with both inches and millimeters.
* Watch in awe as the calipers change size to the correct measurement under your command!
* It's that easy!

We want to hear from you! Let us know what we can do to make this app the best. Contact us at or just leave a review.

NOTE: The "Bolt Marking reference" in the reference section currently contains some incorrect information. A fix has already been submitted and should be posted shortly.

Keywords: Calipers, Bolt, Nut, Measurement, Metric, SAE

What's New in Version 1.4

New and updated graphics have been added to the new version.

iPhone Screenshots

iPhone Screenshot 1
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Customer Reviews

Great for threads, good overall design, but...

The app freezes if you hit the "i" button for more information on the nut sizing screen. I'm guessing that whatever info it's supposed to display would answer the questions I have about how to use the sizing tool (i.e. whether the calipers can be used to find the size nut needed for a bolt or just to identify the size of a particular nut, and where one is supposed to line the nut up—with the calipers or on the displayed nut's inner diameter). If these questions are answered and the info button fixed, it'd be at least 4 stars.

Ok, but doesn't spec BOLTS

As pointed out before, the big know on this app is that, despite the name, it does not give bolt size tools, only nut. They are not the same. Too bad. Otherwise, ya know, fine for the very basics. It would be great (and easy) to include a way to measure the bolt shank.

Useless without update for new screens

This was pretty useful when the nut and thread outlines were the right size. Unfortunately this app was never updated for new phones, so the scale is all wrong for the iPhone6 and 6+. Kind of ruins the whole concept.

Bolt & Nut
View in iTunes
  • Free
  • Category: Utilities
  • Updated:
  • Version: 1.4
  • Size: 1.8 MB
  • Language: English
  • Seller:

Compatibility: Requires iOS 3.0 or later. Compatible with iPhone, iPad, and iPod touch.

Customer Ratings

Current Version:
All Versions: