1. POBCO-B is a special close-grain dense hardwood that is fully impregnated (100%) with a combination of greases and waxes. The lubricant is solid at normal temperatures, flows when heated by friction, and retains lubricating properties indefinitely.
2. POBCO-B bearings are machines cross grain. Due to the natural grain in wood, bearings can be manufatured in two different ways. Bearings manufactured with th e bore of the bearing parallel with the grain are referred to as "Straight Grain" bearings. Bearings manufactured with the bore perpendicular to the grain are referred to as "Cross Grain" bearings.
The tubular cells in wood are the pipelines that feed, meter and reabsorb lubricant. In straight grain bearings, these tubular cells terminate at the end faces of the bearing and do not lead to the interface between the bearing bore and the shaft.
In cross bearings, these tubular cells are cut by the boring operatin during manufacture and terminate at the bearing interface. In service, lubricant is fed directly to the journal surface where it is required.
In rotating shaft, fixed bearing applications, fullest advantage of the cross grain construction of POBCO-B bearings can be taken by installing bearings so that the end grains are 90 degrees from the direction of the applied load. This places the tubular cell ends where they can feed lubricant to the low pressure are of the bearing interface. The shaft carries the lubrican t to the loaded area, where the porosity is at a minimum and maximum film support can develop.
3. POBCO-B bearings are highly resistant to abrasion. This high resistance results from a combination of the relatively softer impregnated hardwood and the continuously self-generated lubricating film it provides. The lubricant in the bearing clearance area tends to repel foreign matter. Small particles reaching the bearing surface become embedded in the bearing wall and are covered by the film of the lubricant.
4. Wood bearings that are machined in a straight grain manner and are not fully impregnated do not exhibit the outstanding characteristics noted above. Premature failure is a likely consequence of using a wood bearing manufactured in an inferior manner. | 
