go SCIENCE OF SUCCESSFUL THRESHING. 



Packing Hand Hole Plates. After the boiler has been 

 cleaned, the hand-holes must be re-packed, for it seldom hap- 

 pens that a gasket can be used the second time. Gaskets, 

 for re-packing, may be purchased, cut ready for use, or they 

 may be cut from sheet rubber packing by the engineer. Other 

 substances, such as sheet asbestos, card-board, straw-board, 

 or rubber belting are sometimes used, but the most satis- 

 factory material for this purpose is two-ply sheet rubber, 

 which is about one-eighth of an inch thick. The gasket 

 should be cut so as to fit closely around the flange on the 

 plate, and should lie flat. The gasket for the bolt head may 

 be made from the piece cut from the center of the larger 

 gasket. Before the hand-hole plate is replaced, the nut 

 should be oiled and screwed back and forth the whole length 

 of the thread on the bolt, using a wrench if necessary, until 

 it may be easily turned with the fingers. The inside of the 

 boiler plate and the face of the hand-hole plate, where the 

 packing touches, should be scraped as clean and smooth as 

 possible. Care must be taken in inserting the plate, to pre- 

 vent displacing the gasket. When the hand-hole plate is 

 in place, the nut should not be screwed down too tightly, 

 when the engine is cold, as the gasket may be injured so that 

 it would not stand steam pressure. It is best to screw up 

 the nut only moderately tight when cold, and turn it up a 

 little more with a wrench when steam begins to show on the 

 gage, and then a little more from time to time until the steam 

 gage shows working pressure. In this way, the rubber has 



