Gear template generator legend:
Tooth spacing
Number of teeth on gear to render for gear.  Controls left gear when showing two gears.
Gear 1 teeth:
Number of teeth on gear to render for gear. Controls left gear when showing two gears.
Printed page width (mm):
After printing a test page, measure the distance between the lines at the top of the page and enter it here. This will scale the image so that the dimensions are exact, and the grid is spaced 1 cm apart.
Contact angle(deg):
The pressure angle of the gears.  For gears with smaller number of teeth, set
this a bit larger, to get more sloped teeth that are less likely to jam.
Gear 2 teeth:
Number of teeth for the gear on the right, if rendered. The checkbox controls whether one or two gears are rendered.
Print gears:
Use this button to get flash to print a vector based image of the gears. Much better rendering than telling your browser to print it.
Shaft hole dia. (mm):
What size to draw the shaft hole. For inside (planetary) gearing, set this larger than the gear to draw a circle around the gear
Show rotated:
Rotate the gears shown slightly. Useful for checking the fit of gears at different angles when showing two gears on the screen. Use values 0 to 100 to indicate percentage of one tooth advance of rotation.
Print gears:
When you print using this button, Flash is told to send its data to the printer. The advantage of this is that the data gets sent in vector format resulting in a much cleaner printout than printing the webpage.
Show pitch diameter
Show the pitch diameter of the gears.  The pitch diameter is the effective diameter of the gear.
Show line of contact
Shows the pressure angle, and the base radius.
Show cm grid
Show a 1 cm grid. Use the "printed page width" to scale exactly to your printer
Turn the gears on the screen. Good for checking meshing of gears with small numbers of teeth.
Dividing plate mode
Sometimes you just want to divide a circle into something like 17 equal parts, and the gear template is handy for that. Checking this option just draws the dividing lines and no gear teeth.