GLOSSARY 



OF TERMS USED IN MECHANICS AND FARM MACHINERY. 



Axis, a real or ima<jinary line, passinu; thioui^h a body, on wliicb It is 

 supposed to revolve. 



Axle or axle-tree, the bar of metal or timber, on the ends of which 

 the wheels of a carriage or wai^on or other wheels revolve. 



Babbett metal, an alloy, usually of tin and copper, for casing the 

 supports of journals, cither for repair, or for easier running. 



Back fukrow, to throw the earth from two plow-furrows together. . 



Ball-cock, a self-regulating stop-cock, closed or opened by the rising 

 or falling of a floating hollow ball. 



Ball-valve, a valve consisting of a loose ball, fitting closely, pre- 

 vented from moving beyond a certain limit. 



Band-wheel, a wheel in machinery on which a band or belt runs. 



Beam, the main lever of a steam-engine, turning on the centre, with 

 the piston rod at one end, and the working-rod at the other. Also, the 

 main timber or bar of a plow. 



Bearing, the part of a shaft or spindle Avhicli is in contact with the 

 supports. 



Bed, the foundation on which a fixed machine rests, as " the heel of an 

 engine." 



Bell-crank, a crank resembling that by which the direction of a bell- 

 wire is changed. 



Bevel-gear, tlie gearing of cog-wheels placed obliquely together, or 

 with the two axes forming an angle. 



Bolster, the cross-bar of a wagon, resting on the axle, holding the 

 box, and through which the king-bolt passes. 



Brake, a lever or other contrivance used for retarding the motion of 

 a wheel by friction against it. 



Breast-wheel, a water wheel where the current is delivered upon it 

 about one-half or two-thirds its height, which distinguishes it from un- 

 dershot and overshot wlieels. 



Bridle, the forward iron on the beam of a plow, to which the team 

 is attached. 



Bjiush-weeel, a wheel in light machinery, turned by friction merely, 

 instead of cogs ; bristles or brushes being often fixed to them to increase 

 the friction of their presshig surfices. 



Bush, the bollow box fitted into the centre of a wheel to take the 

 bearing of an axle or journal. 



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