pulley size and config

I built a I3x kit with a Sagin?????(what ever it's called) motherboard. It had 8 tooth printed pulleys. Yesturday my chineese ebay 12 tooth aluminum pulleys arrived, so I pulled the steppers off, ground flats on the shafts and installed these nice new pulleys.
I researched everywhere tryng to find an 8 tooth replacements in aluminum but was unsucessful.

My question is this: I would assume that when the machine is told to go 1mm for example, the stepper motor is also told to count so many steps per rev. to go that far.
Where is this info stored?
How do I calibrate the motors for correct travel distance?

I will stick a travel indicator on the axis and dial it in dead nuts if i just new where to do it at.

In your firmware configuration.h file is where the steps per mm is defined. You will want to use the calculator to make it easy.

The steps/millimeter information is in the firmware. You will need to access the firmware source code and make the changes. This procedure differs based on what firmware you are running.

Im not really sure what firware is. I loaded all the zipped package that has pronterface. Is it one of those files?

Pronterface is host software. That means it runs on your computer. Firmware runs on the Sanguinololu (Arduino compatible) and will require you to know enough about the configuration.h to make chnages to it and upload the firmware with Arduino software. This is the deep end of the swimming pool so prepare for a steep learning curve. This link might help you: [airtripper.com]

Ok, you can also play with the steps/mm setting using Gcode M92

for example on X-axis: M92 X80.00