Woodworking Woodwork Exercises 15 



the properties of metal from quite other motives than those of 

 constructional rigidity. 



Screws are occasionally necessary, and as a general rule 

 brass screws are to be preferred to iron, and countersunk 

 heads to round ones. These latter give a better appearance 

 to work of composite character (metal and wood), but in 

 screwing them " home " the heads are apt to snap off, all the 

 bearing being taken at this point. It is easy to screw a round- 

 headed screw too far, Le. to give an extra turn after the screw is 

 " home," in which case the head invariably cracks off, whereas 

 a countersunk screw cannot be turned further when once 

 "home." 



IV. WOODWORK EXERCISES. 



The following exercises are selected as involving some typical 

 woodwork, and not simply with the object of producing the 

 article made. Students who are able to complete these exercises 

 satisfactorily will find no difficulty in dealing with most of the 

 woodwork required for the manufacture of Laboratory apparatus. 



Note ; It is recommended that these exercises be worked in 

 the stated order, as instructions given in respect of tools used for 

 the first time are not repeated upon subsequent occasions. 



EXERCISE i. Whitewood stand for Hards apparatus. 



Materials required : Bass wood, 24" x 10" x J", 12" x 7" x i" 

 9" X 3" X }" ; glue ; two i" No. 8 iron screws, one i" No. 7 iron 

 screw. 



Tools required: Jack plane, smoothing plane, tenon saw, try- 

 square, y mortise chisel, i" and J" firmer chisels, turnscrew, mallet, 

 marking gauge. 



Method: Plane up all wood, until a smooth, even surface is 

 reached, and no light appears under the trysquare blade when 

 applied to the wood. This operation is more difficult than would 

 appear at first sight, and is best attained by having the jack plane 

 set so that only a thin shaving is removed at each stroke. Care 

 must be taken to remove the wood from the heights only (which 

 will explain the value of a plane longer than the ordinary jack 

 plane), and the wood must be kept out of twist, and of equal 

 thickness, determined by the use of a marking gauge. 



