Abstract: A blank used for machining customized prosthetic components is provided which includes a prefabricated seating surface, normally shaped as an anti-rotation device, used to seat the component in the corresponding implanted, or natural, surface in the patient's body. Prosthetic components need to be custom manufactured because each patient presents a different need, however, the standardized shape of seating surfaces allows for these to be machined in large scale, without affecting the quality of the treatment the patient receives. Once the customized manufacturing has been completed around the seating surface, the part requires no further machining and is ready to be used.