322 FARM MACHINERY REPAIR 



to reline or refill it. The process of repairing a bearing by 

 pouring in new metal is called babbitting. 



Babbitt is a soft metal consisting of one part of copper, two 

 parts antimony and twenty-two parts tin, melted together. 

 Some of the cheaper grades of babbitt contain some lead and, 

 sometimes, a little zinc. 



290. Babbitting a Solid Bearing. Chip or melt out all 

 of the old babbitt and clean out the retaining holes. Warm 

 the box to prevent the babbitt cooling too rapidly when it is 

 poured. This may be done by holding the bearing in the fire 

 or by placing a hot iron against it. Clean the shaft and place 

 it in line in the bearing, first wrapping one thickness of 

 writing paper about the shaft just the length of the bearing, 

 and fastening it by winding twine about it in a spiral shape. 

 The paper will prevent too tight a bearing, and the space occu- 

 pied by the twine will form oil grooves. Close up the bearing 

 at each end by placing a heavy cardboard over the shaft at 

 each end and puttying up the holes or filling them with soft 

 clay. Reserve the oil hole to pour in the babbitt, or, if it is too 

 small, drive a wooden plug into it clear to the shaft and form 

 a funnel-shaped opening at one end of the bearing with clay. 



Heat the babbitt in an iron ladle until it burns or chars a 

 stick, and gently pour it, if necessary, by means of a funnel, 

 thru the hole reserved for the purpose, first making a few vent 

 holes thru the end protections with a wire. When the bab- 

 bitt is set, and before it thoroly cools, remove the end protec- 

 tions, the plug that fills the oil hole and the shaft. Wipe out 

 the hole formed by the shaft to remove the burned twine and 

 any foreign matter, and the bearing will be ready for use 

 when the babbitt is cold. 



