Pivot

“ I consider it well for young workmen to practice pivot setting in some old and useless watch any spare time they may have, and thus become adepts at this work. Unhindered, I am not over on an average of one-half hour in setting any ordinary pivot, especially if I do not have to cement my work. If this is a balance pivot, be very careful to see that your balance is true and poised before putting on hairspring and roller. ”

“ Don’t you see the left hand is the pivot: if you hold it out as far as you can, then the Long part of the rod is your side of the pivot, and the short little piece is beyond it—then you’ve only got to move that little piece. If you shoot in our old way then the long piece is the other side of the pivot, and of course the least motion makes such a difference. ”

“ Pit′yroid, bran-like. [Gr. pityron, bran.]
Più, pū, adv. more.—Più allegro, quicker. [It.]
Pivot, piv′ut, n. the pin on which anything turns: the officer or soldier at the flank upon whom a company wheels: that on which anything depends or turns.—adj. Piv′otal, of the nature of a pivot: acting as a pivot.—n. Piv′ot-bridge, a form of swing-bridge moving on a vertical pivot.—adj. Piv′oted, furnished with a pivot or pivots.—ns. Piv′ot-gear′ing, a system of gearing permitting the driving-shaft to be swivelled so as to set the machine in any direction with relation to the power ”

“ Run a hole vertically through C and the baseboard for the pivot, which should be 4-1/2 inches long, so as to project 1 inch when driven right home. Take some trouble over getting the holes in L and C quite square to the baseboard, as any inaccuracy will make the lever twist as it moves. To prevent the pivot cutting into the wood, screw to the top of C a brass plate bored to fit the pivot accurately. The strain will then be shared by the screws.
The horns of A should be long enough to allow the outside of the fixed grip to be 2-1/4 inches from the inside of the handle. ”

“ When on a moveable pivot, they are generally used and ordered when the front of the column is small, and its path winding and changeable.
Whenever the wheel, made on a halted pivot, is less than the quarter circle, the pause after the wheel will be considerable; should the wheel be greater than the quarter circle, it must be accelerated, otherwise more than one division will be arrived, and arrested at the wheeling point. ”

“ By keeping the graver on a line with the length of the pivot, all the force applied is simply exerted in the direction of the chuck, and does not tend to spring the pivot, as it would were the extreme point applied, as in Fig. 13. When we come to such places as the shoulder of the back slope, the seat for the roller, balance, etc., we must necessarily use the point of the graver. ”

“ Wheels are made on a Halted pivot from Line into Column, and from Column into Line. The principle of the Moveable pivot must always be applied to the wheel of divisions marching in column. Wheels of divisions may be either made forward, or backward. In progressive movements they are to be made Forward, but particular occasions require that they should be made Backward on the pivot flank. ”

“ Friction of Pivots and Collars.—When a shaft is acted upon by a force tending to shift it lengthways, that force must be balanced by the reaction of a bearing against a pivot at the end of the shaft; or, if that be impossible, against one or more collars, or rings projecting from the body of the shaft. The bearing of the pivot is called a step or footstep. Pivots require great hardness, and are usually made of steel. The flat pivot is a cylinder of steel having a plane circular end as a rubbing surface. Let N be the total pressure sustained by a flat pivot of the radius r ”

“ Neither can we arrive at the proper end shake for a pivot by reducing in proportion from the end shake allowed on a six-inch shaft, because if we followed out the same course of reasoning we would arrive at a point where a pivot measuring 12/2500 of an inch would require an end shake so infinitely small that it would require six figures to express the denominator of the fraction, and the most minute measuring instrument yet invented would be incapable of recording the measurement. ”

“ I am acquainted with watchmakers, and men who are termed good workmen, too, who invariably allow 1/2500 of an inch side shake, no matter whether the pivot is 12/2500 or 16/2500 of an inch in diameter. Now if 1/2500 of an inch is the proper side shake for a pivot measuring 12/2500 of an inch in diameter, it is certainly not sufficient for a pivot which is one-third larger. ”

“ I am inclined to believe, therefore, that the pivot-press may be used with excellent effect in many instances, especially from its simplicity and ease of construction, when a sudden need arises for the accommodation of a new accession of books. I may further draw attention to a special merit—its singular lightness even when full of volumes. A child can work it with ease, unlike the sliding-press, which, when quite full, may tax the strength of a powerful man. ”

“ The acid simply rusts the pivot and the hole, but I cannot see that this will hold it any more firmly in place while finishing. If the taper is a gradual one and the pivot a good close fit, there will be little danger of it loosening while dressing to shape. If too great a taper is given to the plug, there is danger of splitting the end of the staff, and this involves the making of an entire new staff. ”

“ By simply pressing on this mechanicismmechanicism, the latter checks the motion of the wheel by application of friction at the pivot, and brings it to a standstill at any point which he may desire.
Not always, however, is the proprietor of the wheel the only sharper on the ground. Sometimes he discovers, when it is too late, that he has been playing a game of “diamond cut diamond.” ”

“ The upper pivot, or bearing is made of tempered steel wire and of sufficiently small diameter to be quite flexible in the length between the top of the brass shaft and the guide ring in which it rotates. ”

“ Using one foot for a pivot, he keeps moving round by the aid of the other, so as make about ten revolutions in a minute, and, while in motion, successively takes the eggs from the basket, and, with his right hand only, puts each into a loop, drawing it tight, so as to retain the egg firmly in an equipoised state. ”

“ For pivots band b and e may use brass screws and small pieces of hard wood as nuts to hold them in position. The nuts should screw on rather stiffly, and not be forced hard against the rods, as free motion with little friction at all joints is essential for good work.
[Illustration: FIG. 187.—Diagram showing how to mark off pantograph rods. The dotted lines above rod give distances of holes from ends.]
The fixed pivot at a may be merely the shank of a wire nail of the proper size driven into the board, a cork collar being slipped over it to keep the rod the proper distance from the board. ”

“ Wheel made to the reverse flank. When [744] the change is made to the REVERSE hand, the pivot leader having arrived as before, at the spot where he gives his word right or left quarter wheel! for each man to give a small turn of his horse’s head FROM the pivot hand, will begin in his own person to circle BEHIND the line from the old, so as to enter the new direction twenty or thirty yards from the point of intersection, which, in this case, he leaves at some small distance WITHOUT his pivot hand. ”

“ Each division on the gauge represents 1/2500 of an inch, which is all that we require. The diameter that the pivot should be, can be ascertained by inserting a round pivot broach into the jewel and taking the measurement with the pivot gauge, and then making the necessary deduction for side shake. Slip the jewel on the broach as far as it will go, as shown in Fig. 12, and then with the pivot gauge, take the size of the broach, as close up to the jewel as you can measure, and the taper of the broach will be about right for the side shake of the pivot. ”

“ If once you move your pivot foot, you lose that self-command essential for leg-hits. So, practise, In your garden or your room, the stride and swing of the bat, till you have learnt to preserve your balance.
One of the best leg-hitters is Dakin: and his rule is: keep your right foot firm on your ground; advance the left straight to the pitch, and as far as you can reach, and hit as straight at the pitch as you can, just as if you were hitting to longfield: as the lines of bat and ball form an angle, the ball will fly away square of itself. ”

“ One member of each team takes a position on the distance line, opposite to and facing his team. At the signal to go the first man on each team runs forward, locks his right arm in the right arm of the man on the distance line and in this position spins twice around, using the man on the distance line as a pivot. Completing his second spin, he remains on the distance line while the man who was there returns and tags off the next member of his team, who repeats the performance. The race ends when the last man to spin around the pivot crosses the base line. ”

“ This keeps the ball down and drives it in the direction required. In cutting, the left foot acts as a pivot, and the right foot is drawn back. The advantage of taking a long block is here shown, as occasionally this leg knocks down the wicket; and if the block is near the stumps, they are easily struck by the bat itself. ”

“ Some of my readers may think that I am over-particular on this point, and that the difference in measurement on two occasions is too trivial to be worthy of attention, but I do not think that too much care can be bestowed upon this part of the work, and neglect in this particular is, I [Pg 24] think, the cause of poor performance in many otherwise good timepieces. The ordinarily accepted rule among watchmakers is that a pivot should be made 1/2500 of an inch smaller than the hole in the jewel to allow for the proper lubrication. ”

“ If [Pg 42] your drill is made from a piece of Stubb's steel wire, or an old French or Swiss graver, you not only know that the material in it is first-class, but you can leave the base of the drill solid and substantial, with enough metal in it to resist considerable pressure. The part of the drill which actually enters the pivot is very short, and the end can be turned down to the desired diameter. Turn or reduce your wire by means of a pivot file so as to be smooth and conical, as shown at A, Fig. ”

“ When the animal passes under and between the two pivots, he treads upon a lever which throws the beam off the pivots, and it falls with full weight on the animal, forcing the spikes their full length into its body. ”

“ A round broach will answer admirably for this purpose, and the size may be taken from the broach by means of the calipers. In fitting our pivots, we can not be too exact; and as yet no instrument has been placed upon the market for this purpose which is moderate in price and yet thoroughly reliable. The majority of watchmakers use what is termed the pivot-gauge, a neat little instrument which accompanies the Jacot lathe, and which may be obtained from any material house. This tool, which is shown in Fig. ”

“ Damaged pivots can often be detected by looking through the end stone with a strong glass while the balance is moving. If imperfect they will appear dark or display a slight waver or flash and if they are in good condition they will appear bright and seem to stand still. They can also be examined in the lathe and a good true enclosed balance chuck is of immense value in detecting burrs, chipped edges, rings on the sides, slight bends and poorly shaped ends. The complete balance and spring can be inserted and the pivots can be refinished without disturbing the roller or hairspring. ”

“ By a system of pivots and bars, 16 or more points are maintained in a straight line and at equal intervals, while the space between two successive points may be drawn out from one-eighth inch to one inch. ”

“ I have seen staffs that were models as regards execution and finish, that were nearly worthless from a practical standpoint, simply because the maker had devoted all his time and energy to the execution of a beautiful piece of lathe work, and had given no thought or study to the form and size of the pivots. On the other hand, one often sees staffs whose pivots are faultless in shape, but the execution and finish so bungling as to offset all the good qualities as regards shape. ”

“ The main object of the invention is the substitution of this torsional spring for the ordinary pivotal support previously used, which consisted of tapering pivots or gudgeons projecting from the sides of the lever into the bearings. The testimony indicates that the pivots require very exact construction and adjustment; that they are apt to wear loose in their sockets; and that inexperienced operators are apt to turn the screws, which carry these sockets, too far or not far enough, thereby rendering the motion of the lever either too difficult or too easy. ”

“ The next man held his bat firmly in the block-hole, as the best means of combating the third [Pg 98] ball of the over,—the fast yorker,—and with the assistance of short-slip, who received the ball in the pit of his stomach and incontinently dropped it, disappointed the entire field, friend and foe alike, by spoiling Pip's hat-trick. The batsman, a person of unorthodox style, having succeeded in despatching a yorker to slip, decided that the best place for a good length ball would be long-leg. He accordingly stepped in front of his wicket for the purpose of carrying his intention into effect ”

“ Once more it was Pip's turn. He found himself confronted by another hard slogger, who, instead of sticking to his last, trusting to his eye, and running out to hit, stood stock-still, and having solemnly planted his bat in what he imagined was the path of the ball, awaited developments. The ball, curling like a boomerang, pitched slightly to leg, broke back, and bowled him. Six for forty-nine.
The frenzy of the Hivites was becoming almost monotonous, and it was hardly capable of augmentation when Pip bowled another man with his next ball, bringing his analysis up to five wickets for no runs. ”