Oil soaked wood bearing
Practical Action
Other considerations
High moisture content causes a reduction in hardness and results in greater wear. For most
applications low moisture content is preferred and excess moisture must be removed to
prevent subsequent shrinkage especially if the bearing is to be used as a bush. The hardest
wood is to be found in the main trunk just below the first branch.
Bolt hole
Axle
hole
FigurAex1l:eOne–piece block bearing
Grainhodlierection should be considered, and if possible advantage taken of the close grain to
provide hardness at the wearing surface.
The piece of timber selected for the bearing should be free from cracks. Some suitable
timbers are listed in Table 1.
"Greasy” woods Lignum vi tae ( Guaiacum officinale )
Tallowood (Eucaliptus microcorys)
Teak (Tectona grandis)
Blackbutt (Eucaliptus pilularis)
Other woods Poon (Calophyllum tomentosum)
Hornbeam ( Carpinus betulus )
Degame (Calycophyllum carididissimum)
Boxwood (Phyllostylon brasiliense)
Pear (pyrus communis)
Oak (Quercus robur)
Camphorwood (Dryobalanops aromatica)
Table 1: Suitable timbers
If the timber is not of the self-lubricating variety (or of doubtful self-lubricating
characteristics) it can be soaked in oil to minimise the need for subsequent lubrication. It is
important to have dry wood to assist maximum absorption of oil.
Construction
The following notes relate to experience gained in the field manufacture and testing of three
types of wood bearing. All were of the oil-soaked variety.
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