Well are ya? If you are and are going to use 1/2" ACME rods, have I got a deal for you. DumpsterCNC.com sells these Derlin threaded couplers. they are great! very well made. I ordered the wrong ones. These have the motor shaft size as .25 and are threaded for the 1/2" ACME rods. On their site they are $17.50 each plus shipping.
YOU GET ALL 3 SHIPPED (US only) for $35.
My moronisism is your prize.