Here's a program I authored in Visual Basic to take the dirty work out of performing the routine calculations in design of mechanical systems involving spur gears.  It runs in Windows 95/98 or later.  A help file is included (look for it in the installation directory).

Downloads:

DAK Spur Gear v1.07 Files only - 44k

DAK Spur Gear v1.07 Full installation - 716k

All VB 5.0 programs require this run time library (MSVBVM50.DLL).  You probably have it on your system already, but if you don't then here it is.  Unzip it to your windows\system directory.  THIS FILE IS NOT INCLUDED IN THE DOWNLOAD ABOVE!

MSVBVM50.ZIP - 704k

Sample screenshot: