CAURIAGE AND WAGON MAKING, 53 



are called curls. Dark veins (as in walnut, zebra wood, sissu, some 

 specimens of teak, &c.), a regular wavy fibre (as in many specimens 

 of tun and sissu),. or a satiny appearance due to conspicuously 

 bright shining medullary plates (as in satin wood, tun, mahogany, 

 padouk, maple, oak, &c.), also increase enormously the value of wood 

 for the purpose of the cabinet maker. To diminish cost many articles 

 are only veneered with the handsome kinds of wood. Veneers are 

 thin sheets of wood taken off with special saws and by a special 

 process. For curved articles the grain of the wood must be ex- 

 tremely even and coherent, the best kinds being teak, ebony, black- 

 wood, sissu, walnut and deodar. 



Other qualities required in cabinet-makers' and joiners' wood 

 depend on the conditions in which any given piece is used. Thus 

 the various parts of a chair and table should be very strong. The 

 wood for portable furniture, such as chairs, should be light, 

 while tall articles, especially those which have a narrow base, 

 require heavy wood below. The sides of drawers should be able to 

 resist friction. For the manufacture of bentwood furniture flexible 

 young wood is necessary.* And so on. For all articles which 

 stand away from walls and round which the air circulates freely, 

 the question of durability is of entirely secondary importance. 



AnTiOLE 7. Wool) USED IN Caeeiage and Wagon making. 



Wood used for this purpose should be as light as possible con- 

 sistent with the requisite strength, hardness and elasticity. The 

 only portion which forms an exception to the rule is the frame- 

 work of high carriages, which must be heavy in order to keep the 

 centre of gravity low. 



The most important part of a carriage or wagon are the wheels. 

 An ordinary wheel consists of a nave (or hub or hob) and of 

 spokes and felloes. 



The nave must be able to resist great and violent shearing strains, 

 and the wood must be so dense and hard, that these should be un- 

 able to enlarge the mortises or holes in which the spokes are fixed 

 and thus render the latter loose. It should contain no sapwood. 



* The process of manufacture is as follows : — The timber is sawn up into strips 

 from I^ to 2 inches square, according to the work for which it is intended, and 

 then turned in a lathe into smooth round rods. These rods are exposed in an 

 air-tight case for fifteen minutes to the action of superheated steam. They are 

 then so soft and pliable as to be easily bent by hand, and are in this condition 

 fitted to iron patterns well secured. When the pieces are dry, they are detached 

 from the pattern and retail) permanently the shape given them. 



