new to arduino, need some motor use advice

I have a motor that is about as strong as a hand drill motor, and I need to rotate it in one direction with its max torque and then rotate it in the other direction slightly, maybe with 1/4 torque, and would cycle between full rotate in one direction to a slight rotation in the other about 80 times in one minute. I have access to many transistors,diodes, resistors, and an ardunio board, but how could I easily, reliably, and safely implement this?

thank you!

You probably need to use an H-bridge to control the motor. Search the forum for h-bridge for hundreds of post on the subject.

i looked more into the H-bridges, thanks

I was just wondering, that if i had a motor and it would need to spin right for 3/4 of a second then 1/4 left and that one second being one cycle being repeated for one minute if I'm putting too much strain on the motor to be constantly rotating one direction then in another in a short time period. Or if there is any other way i could approach this problem?

Spinning a motor for an amount of time is fairly easy. If it needs to go to a specific position, then things get more complex. You can start testing your timing code just using the built in LED on the arduino board (check the "blink" examples).

i found a schematic

http://www.pocketmagic.net/wp-content/uploads/2009/03/hbridge-radu1.jpg

which seems good for my application, but somethings were unclear to me, is it if i were to apply a PWM input on the left and 0 input on the right the motor would spin right? and vice versa if a PWM input was input on the right and 0 on the left would the motor spin left?

thanks :)

or also if anyone could just help me figure out the flow of the circuit if one input is turned on and the other off/ vice versa?