[Fig. 2.] and [4.] shew how the Harrow’s Leg B is held to the Piece A, by the Pin C. The Letters a b shew the Holes through which the Pins do pass to screw the Piece A up to the Plank, and the Limbers for guiding the Harrow. This Piece A is somewhat longer than the Breadth of the Plank; it is about Two Inches thick, and Two and an half in Depth. The Pin [Fig. 3.] goes through this Piece near the Bottom of its fore End, whereby the Harrow tines have the more room to rise up, without being held down by the Legs pressing against the Plank.
[Fig. 3.] is the Pin C, of [Fig. 2.] a is its Head, b its round Part, whereon the Harrow moves; c is its square Part, that prevents its turning, which by the Motion of the Harrow would unscrew the Nut d, and cause it to come off of the Screw e, and be lost.
The Harrow is also shewn in [Fig. 1.] as it is guided by the Pieces before described: B is its Head, that holds the Tines D D, drawn by the Legs C C. Tho’ these Legs in Plano seem in their Middle to crook sideways, yet when out of Perspective, their Middles crook only downwards; which is to give the greater Length to the Tines, and the more room for them to move up.
[Fig. 5.] is the Spindle in Three Parts. A is the middle Part, wherein are the Notches b b. This is best to be of Oak, or some other hard Wood, in which the Edges of the Notches are less apt to wear than in softer Wood; but I have had a Set that have lasted the Drilling of 120 Acres, when made of Ash. B and C are the Two other Parts: D and E are their Ends, whereon the Wheels are put. The Holes h h h h, and the same in the other End under the Letter E, are for setting the Wheels at different Distances, in order for making new Notches, or for different-sized Ridges: The Wheels are held in their Places by long Nails put through some of these Holes, and clenched upon the Iron Stock-bonds to prevent their falling out. These Ends B and C need not be cut to a Square; except just enough to prevent the Wheels from turning on the Spindle.
These Three Parts are grafted together by Help of the hollow Cylinder [Fig. 6.] which, being put on upon the Joint f, of the Spindle [Fig. 5.] holds the Parts A and B together by the Two Pins a a, passing through the Cylinder near its Ends, and through the Holes k and g.
This Joint may be in another manner; viz. One Part of the Spindle may enter into the other by cutting it to a square Peg of an Inch long, and ³⁄₄ths Diameter, entering an Hole that fits it, at the End of the other Part.