Tools and methods for preparing an intervertebral disc space with an emphasis on abrading the vertebral endplates to promote controlled bleeding of the vertebral endplate without compromising the structural integrity of the vertebral endplate. Mechanisms to statically or dynamically alter blade angle of the cutter blade. Cutter blades may come in a variety of configurations including cutter blades with abrading heads for preparing endplates. Abrading heads may be used on upcutters or down cutters. A cutter assembly adapted to resist unwanted changes in blade angle.