66 PATTERN MAKING 



and the result will be a right and left slanting line, having, vvitli 

 reference to the perpendicular, ^i slant of inch to a foot. These 

 lines should each be marked ' inch," as shown in the drawing. 



Now draw a second perpendicular <?, at a distance of 1| inches 

 or 2 inches from the first. On the edge of the board a, again 

 carefully mark off \ inch on each side; at the other extreme mark 

 off -nr inch on each side of e, and again connect the latter points with 

 the former. The result will be a taper of -fa inch to a foot. Again 

 repeat the process, making the taper \ inch, and lastly inch, to a 

 foot. Mark the pairs of right and left-hand tapers respectively i 

 inch, 1%- inch, \ inch, inch, as shown. These lines having been 

 obtained permanently, the width of the board may be cut down 

 from 12^ inches to 6 inches (as shown by the dotted line A B), and 

 the board then shellaced. 



To use this template, place the bevel against the edge a of the 

 board, and carefully adjust the blade to the inch, $ inch, or 

 other draft, right or left as may be required. It will readily be seen 

 that whatever may be the width of the surface to which the bevel 

 is applied, the taper or draft will be in the exact proportion of the 

 given amount for each 12 inches. 



Finish. The term finish, in pattern making, refers to the 

 additional amount, after shrinkage and draft, which must be added 

 to the pattern in places where the casting is to be planed, turned, 

 chipped and filed, or "fitted," in the machine shop. The amount 

 that is to be so added is, to a certain extent, though 

 not wholly, independent of the size of the piece. For small 

 articles whose longest dimension does not exceed three or four 

 feet, an addition of inch to the surface to be finished is usually 

 sufficient. For larger dimensions it may be necessary to add as 

 much as \ inch or inch, but very rarely more than this. In 

 making this allowance it is also well to bear in mind the tendency 

 of the casting to warp in cooling. Where the thickness of the metal 

 varies to any great extent, there is a greater liability to warp than 

 if a uniform thickness prevails throughout the whole. Hence, in 

 such cases, a greater allowance must be made for the finishing. 



On small pieces and where the moulding is carefully done it 

 may be possible to make as small an allowance as -,V inch, but as a 

 general rule sufficient metal should be put upon the casting to allow 



