Description: 4-bolt flange units are bearing housing units featuring 4 bolt holes, giving them a square shape; They can be used in applications where ample space is provided for mounting the housing unit, and provide substantial mounting security for high load applications. Flange housing units are used when the bearing mounting surface is perpendicular to the shaft axis. Often the insert bearings can be adjusted or aligned within the housing to accommodate long shafts. Most manufacturers offer flange units in two series: inch dimensions and metric dimensions. Flange unit materials include cast iron, thermoplastic, glass filled PBT polyester, stainless steel, and other metals. Plastic housing units require minimal to no maintenance, and avoid rust and corrosion, however they may not be suitable in high temperature applications.Different features are also available; housing units may include a grease fitting for adding lubricant or slingers on the sides for dust protection. Flange housing units are either set screw locking type, sleeve collar, or eccentric locking collar locking type for one directional applications. A multitude of bearing inserts with varied materials and seal types are available with these housing units. Chrome steel bearings are regreaseable and often paired with cast iron units. UHMW-PE bearings are designed for applications in wet or harsh environments, are self-lubricating, and can be used with most metal housings. Bronze bearings are preferred for lighter applications and continuous lubrication. Stainless steel, nickel, and plated zinc are also available, depending on the manufacturer. Inner ring width varies depending on the load capacity needed; narrow inner rings are more suitable for light duty applications. MRO Supply carries a wide range of 2-bolt flanged housing units from various brands, sizes, materials, and bearing types to suit any application.