Grayline 40552, 3 Shelf Gourmet Spice Rack, White Item # UCP312-207D1, Pillow Block Unit, Cast Housing, Set Screw, UCP/UCPX Type On NTN Bearing Corp. of America Housing material for a pillow block is typically made of cast iron or cast steel. Suit Collars / UCP210-31 / Pillow Block ounted Ball Bearing 1 15/16... 2-Bolt, 1 15/16 Inner Diameter(I.D) With this configuration, the pillow block is bolted to a foundation, securing it, while the shaft and the inner ring of the bearing are free to rotate. 5/8 Bolt Size with Set Screw Collar 1 Pillow Block Bearing Summit Collars / UCP210-31 / Pillow Block Mounted Bearing 1 15 16 Bore Solid Cast Iron Base Self Aligning 1 Piece Mounted Pillow Block Bearings