That shield is really not suitable for driving that type of motor. It's like putting petrol (gas) in a diesel engine. It will run for a while but not very well and it's going to get damaged.
Look for anything with an A4988 or DRV8825 chip in it. Those two chips are both very good at driving stepper motors of that size.
While you're waiting for the stepper drivers to arrive on the back of a camel (and a spare motor to replace the one you're going to burn up) can you increase the voltage of your power supply? That will increase the current.
Really appreciate this useful information thanks mate =)
I had a similar problem with the adafruit motorshield, their bus speed is too low and can't run 2 stepper fast at all. I would recommend the A4988 as stated above. I realize you said you are stuck with the shield, but frankly I learned the hard way that those shield really are not that useful. Are you looking for higher speed (rpms)?
Yeap i'm trying for higher speed as the motor is not behaving as how it suppose to be. I'm totally getting over this shield as it is not useful at all for me
You will need a stepper controller that has a current limit facility.
The Adafruit unit does not have the current rating or the current limiting facilities.
Thank you so much for the information as i'm really new to this motor thingy
Its a low impedance stepper motor, you cannot drive those with a DC motor shield.
You require a current-controlling stepper driver like a DRV8825
Thanks for the info =)