Cast baseplate for a disk drive having an arcuate shroud wall and adjacent arcuate groove

A disk drive includes a cast baseplate, and a disk having a major surface and an outer circumference. The cast baseplate includes a casting inlet gate region, a planar area underlying the disk, an arcuate shroud wall that is substantially orthogonal to the planar area, and an arcuate groove immediately adjacent the planar area. The planar area is separated from the disk major surface by less than 0.8 mm. The arcuate shroud wall is disposed less than 0.8 mm from the disk outer circumference, and includes a first shroud wall portion and a second shroud wall portion. The first shroud wall portion is more proximate to the casting inlet gate region than is the second shroud wall portion. The arcuate groove is immediately adjacent the first shroud wall portion, and defines a groove depth in the range 0.2 mm to 2 mm relative to the planar area.