Yes to all who suggested how to pack them. Then, I'd check out FedEx if it's in your area. With the size of hard drives plus packaging, I'm not sure you're going to be able to use the flat rate boxes to their maximum value. FedEx has good rates if you go up close to 70 lbs (but not over) and even better if you set up an account with them. I've had good luck with them not breaking stuff also.