Thank you for the information. I am going to use 16x4 or 20x4 leadscrews so I should be able to get the speeds i want. I have found the AM882 drivers here (http://www.aliexpress.com/item/New-L...570168083.html) Would you agree with getting these ones. I will aim to make a 70vdc linear power supply with soft start. As i mentioned above and am looking to use leadscrews for all the drive mechs, however i need to find some nuts. Does anyone know of a cheap source of leadscrew (Trap) nuts? Thank you so far