488 CONSTRUCTION, FARM ENGINEERING, MECHANICS 



inches in diameter, and carefully split down the middle. The heaviest 

 and best slab should be selected for the front. At a point on this front 

 slab 4 inches from the end that is to be at the middle of the road 

 locate the center of the hole to receive a cross stake, and 22 inches 

 from the other end of the front slab locate the center for another 

 cross stake. The hole for the middle stake will lie on a line connecting 

 and halfway between the other two. The back slab should now be 

 placed in position behind the other. From the end which is to be 



FIG. 20. The split-log road-drag. 



at the middle of the road measure 20 inches for the center of the 

 cross stake, and 6 inches from the other end locate the center of the 

 outside stake. Find the center of the middle hole as before. When 

 these holes are brought opposite each other, one end of the back slab 

 will lie 16 inches nearer the center of the roadway than the front 

 one, giving what is known as " set back." The holes should be 2 inches 

 in diameter. Care must be taken to hold the auger plumb in boring 

 these holes in order that the stakes shall fit properly. The hole to re- 

 ceive the forward end of the chain should be bored at the same time. 



The two slabs should be held 30 inches apart by the stakes. 

 Straight-grained timber should be selected for the stakes, so that each 

 stake shall fit snugly into the two-inch hole when the two slabs are in 

 the proper position. The stakes should taper gradually toward the 

 ends. There should be no shoulder at the point where the stakes enter 

 the slab. The stakes should be fastened in place by wedges only. 



When the stakes have been placed hi position and tightly wedged, 



