TapDrillTool for iPhone and iPod Touch
Need to know what drill bit to use to tap a hole for a screw or bolt? Or maybe you just want to drill a thru hole for one.
TapDrillTool make is REALLY easy to find out.
No tables to scroll through, no screw selection pages - just dial in the screw size, pitch and desired engagement percentage and your options are displayed instantly. You'll see the optimal hole size and the bits that come closest to your request, along with the resulting engagements and hole size errors.
You can buy TapDrillTool either from iTunes or by visiting the App Store on your device. In either case, searching for "TapDrillTool" will get you to it. Or, you can use this link
to start up iTunes on your computer and go straight to it.