"You want to know when to stop driving. The time has arrived when a pile penetrates very little, and nearly equal for several successive blows of the heaviest ram by which it has been driven at the usual fall.
"A word as to tie and sheet piles before referring to the way I have worked piles for 'extra' profit. It is difficult to make a main pile and a tie act together, one or the other is nearly sure to have to bear more than its proper strain, and the tie rod becomes eaten by rust, bent, and loose in the piles. In taking down old banks and quays you will generally find the main pile and the tie pile are not held tightly by the tie rod, the tie pile is loose or pulled over, perhaps when first strained, and then becomes disengaged when the main pile has set to the strain. The tie rods want to be very carefully and frequently adjusted, if possible, and big washers and cleats on them are required. They hold best in firm sand, not so well in clay, and in large light loose soil, such as ashes, they are not much good. It is an impotent arrangement and it is always uncertain whether they will act together. Don't undertake to tighten up the rods. Fix the piles, and let the engineer see to the tightening up, as you may injure the piles.
"When I have to drive a lot of sheet piles, of course the piles are supplied to me, and I only take the driving. You may be sure the timber is right, and that the edges are sawn square so as to drive tightly together, and that the point is in order. I find it always pays well to temporarily place a baulk at the ground line like a waling, but not fixed to the sheet piling, as it guides the piles, lessens the shaking, and they drive easier and better. It appears to me piles cannot vibrate without force, and that is not where it is wanted, so it is wasted motion. Agitation when drawing piles is all right, but when you are driving you want it in the ground itself, and not in the piles. Once when I had to drive some thin sheet piles, I made a movable guide frame, the side against the sheet piling being planed and greased. It was like one bay of a timber-lattice bridge, and it well paid for itself as it steadied the piles.
"In taking a contract for drawing piles always find out how long the piles have been driven, for if they have been down many years they will be much harder to draw than if they have only been fixed a few months. They can be drawn by lever, hydraulic jack, and chains, and pontoons in a tide way."
CHAPTER VI.
TIMBER PILES.
Manipulation for "Extra" Profit.
"Now, I'll tell you about a bit of 'extra' dodging that rather scared me. First, let me say, no one can ever know how much I hate waste—it can't be measured."
"You and me are alike, a couple of turtle doves on that question."