I have a small engraving machine that I'm hoping to get up and running to cut some pcbs. the current set up uses 6 wire steppers running of a unipolar drive. I can't easily tap into the divers so looking to replace them with new drivers.

I have looked around and I can run them as 4wire on a bipolar drive but will either have to lose speed or torque depending on which coil I use. existing PSU is 50v and my drives are 50v so not much option to up the voltage

Is it worth driving the old motors in bipolar or will I lose to much speed or power?

Ultimately I will upgrade the motors etc. but I could do with a quick fix to get it working to finish some other projects moving.