18 



Laboratory Arts 



such a place as to produce a triangle of maximum size (A). A 

 line should be scribed on each side of the piece, and another should 

 be scribed J" from the face, all round the newly made triangle: 

 Saw cuts inside the line along A, on both sides, and others outside 

 the line to meet these down the grain, will cut away two cheeks 

 and leave a tongue which projects into the base of the stand 



FIG. ii. 



() (*) 



FIG. 12. (a) Elevations. 

 (b) View of back strut. 



already made. The saw cuts should be made by fixing the wood 

 in the bench vice, and commencing to cut along one of the scribed 

 lines, penetrating the surface as little as possible, until the line has 

 been traversed, when the saw should be sloped, and the second 

 line similarly cut ; these cuts will then serve as guides to the saw 

 in the subsequent cutting down to the line A, which may now be 

 proceeded with, holding the saw parallel to A. 



Place for this tongue is now scribed out on the base board of 

 the stand, and two saw cuts made (sawing on the inside of the line) 

 at right angles to the slot already cut, which will permit the access 

 of the saw. After removing the surplus wood with a J" firmer 

 chisel, the triangular piece may be fitted to the groove just cut. 



Before erecting, it will be well to cut the holes in the face, 

 cutting half way from each side, one f" diameter, and two J" or " 

 diameter in the positions indicated, the wood between these two 

 latter holes being sawn out ; also to cut J" shoulders on the 

 tongue of the upright piece, as shown in Fig. 13. Two saw cuts 

 may also be made about " from the outer edge of the tongue, 

 as indicated in Fig. 13, and about i" long. Two wedges, the 

 thickness of the wood cut from the two corners, 2" long and J" 

 wide at the thick end, should also be cut, and a -" hole drilled at 

 right angles to the tongue of the back stay through the base, and 

 countersunk to take the head of the larger screw. 



