Hi bit of a noob here. I am more mechanical than electronic. I have looked at using uln2003 to drive a unipolar stepper. Due to the simplicity of the layout and sketch. I was wondering if i could stack these ics to achieve a higher current rating. (Again this is coming from my mechanical background). Any advice would be appreciated.

Literally from the first page of the datasheet:

The collector-current rating of a single Darlington pair is 500 mA. The Darlington pairs can be paralleled for highercurrent capability.

But I would only do that with outputs of the same IC, not by stacking IC's to minimize internal differences.

But keep in mind, the total continues current the uln2003 can handle is NOT 7 x 500mA = 3,5A. It's less because of the heat dissipation. Without cooling it's like 1,2A or something.