The IAP Bushings & Tubes app provides a searchable and sortable interface to over 1600 pen kits from most of the major kit suppliers. The app displays detailed tube and bushing specifications and drill bit requirements for every kit in the app database. These kit details can be emailed or printed via Air Print. You can create a favorites list of your most frequently used kits for faster access to those kits rather than searching through the entire app database every time you need to reference those kits. You can also reorder the database by your preferred supplier order.

The app also includes a drill bit converter for converting between inch fractional, inch decimal, metric and gauge drill sizes. Conversions to inch fractional are made to the nearest 1/64" and conversions to gauge drill size are made to the nearest gauge drill size (107-1 and A-Z). An error factor is displayed for inexact conversions to inch fractional and gauge drill size.

A 30-digit, 4-function calculator is included in the app. It has several advanced features not found in many simple calculators including a memory cell and the ability to display data in decimal or scientific notation.

Photos, Instructions and Bushing Drawings are available for some of the kits. When instructions or bushings are available, they may be viewed, mailed or printed.

The app will automatically download database updates and the kit reference files from the IAP server.

What’s New

Version 1.07

This app has been updated by Apple to use the latest Apple signing certificate.

Updated for iOS11 and new devices
Some bug fixes

Ratings and Reviews

4.4 out of 5
8 Ratings

8 Ratings

Old Sternwheeler ,

Ton of info, no search feature

There is a lot of great information here. Whoever compiled this deserves a tip of the cap.
One real drawback, however, is that the pen names are organized in about 8 or 10 different alphabetical sets. There's no way that I have found to sort or search. So you scroll, and scroll, and scroll until you find the pen you need.
I'm sure I'll eventually figure out where my favorite pens are located in this almost endless list, but in the meantime, some frustration.
Despite my complaints, it's absolutely worth $.99.

Developer Response ,

Thanks for your review. There are actually a number of ways to sort and search the data. You can reorder the suppliers, create your own list of favorite kits, sort the list by a number of different criteria, and search for kits using most any alphanumeric string or combination of strings. The app includes a Users Guide that explains all these features that you can view in the app or print or email it. Please send us an email to and we will be happy to answer any questions you might have.

Gryphon RIder ,

Great app

For what it does, but the database hasn’t been updated in ages. A lot of the newer pen kits are not in it, so it limits its usefulness.

Rv240 ,

Needs updating

It’s been a while since the app data base has been updated, so it is missing the newer kits. As well as the default screen doesn’t let you scroll up to get access to the sort feature, so the only way to search the kits is to type and search by name or to scroll.

App Privacy

The developer, LLC, has not provided details about its privacy practices and handling of data to Apple.

No Details Provided

The developer will be required to provide privacy details when they submit their next app update.


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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