Part 7 (2/2)

71 such a device Toneedle--the kind known as a milliner's needle is about the best The diameter of the needle should be about No 2, so that at _b_ we can drill and put in a small screw It is ith of the needle should be about 1-5/8”, in order that from the notch _a_ to the end of the needle _A'_ should be 1” The needle should be annealed and flattened a little, to give a pretty good grasp to the notch _a_ on the pallet staff

Good judg this claive exact measurements About 1/40” in width when seen in the direction of the arrow _j_ will be found to be about the right width The spring _B_ can be ree in width with the part _A_ In connection with the device shown at Fig 71 we need a ht as possible above the bench The idea is, when the clamp _A B_ is slipped on the pallet staff the index hand _A'_ will extend outward, as shown in Fig 72, where the circle _C_ is supposed to represent the top plate of a watch, and _A'_ the index hand

HOW THE ANGULAR MOTION IS MEASURED

[Illustration: Fig 72]

Fig 72 is supposed to be seen from above It is evident that if we re power on the train, and with an oiling tool or hair broach move the lever back and forth, the index hand _A'_ will show in a ular motion of the lever Noe provide an index arc, as shown at _D_, we can measure the extent of such73]

[Illustration: Fig 74]

To get up such an index arc we first73 The arc _D_ is ree with the index hand _A'_, and is divided into twelve degree spaces, six each side of a zero, as shown at Fig 74, which is an enlarged view of the index _D_ in Fig 72 The index arc is attached to a short bit of wire extending down into the support _E_, and ht by the set-screw _l_ Let us suppose the index arc is adjusted to the index hand _A'_, and we ested; you see the hand would show exactly the arc passed through froe so the zero mark on the scale stands in the center of such arc This, of course, gives the angular motion from bank to bank

As an experis so they arrest the fork at the instant the tooth drops frorees, the pallet action is as it should be with the majority of modern watches

TESTING LOCK AND DROP WITH OUR NEW DEVICE

Let us try another experiment: We carefully move the fork away froh one and a half degrees the fork flies over, we know the lock is right We repeat the experiment from the opposite bank, and in the saht on the other pallets You see we have now the ular ular extent of the lock At first glance one would say that if noe bring the roller and fork action to coincide and act in unison with the pallet action, ould be all right; and so ould, but frequently this bringing of the roller and fork to agree is not so easily accomplished

It is chiefly toward this end the Waltham fork is made adjustable, so it can be moved to or from the roller, and also that we can allow the pallet arms to be s the pallets are all right; but to testand put the balance in place Now, if the jewel pin passes in and out of the fork, it is to be supposed the fork and roller action is all right To test the fork and roller action we close the banking a little on one side If the fork and jewel pin are related to each other as they should be, the jewel pin will not pass out of the fork, nor will the engaged tooth drop from that pallet This condition should obtain on both pallets, that is, if the jewel pin will not pass out of the fork on a given bank the tooth engaged on its pallet should not drop

We have now come to the most intricate and important problems which relate to the lever escapement However, we promise our readers that if they will take the pains to follow closely our elucidations, to make these puzzles plain But arn theood, hard thinking The readiest way to master this matter is by means of such a model escapement as we have described With such a model, and the pallets made to clamp with small set-screws, and roller constructed so the jewel pin could be set to or from the staff, this matter can be reduced to object lessons But study of the due relation of the parts in good drawings will also master the situation

A FEW EXPERIMENTS WITH OUR ANGLE-MEASURING DEVICE

In using the little instruular motion that we have just described, careclamp which ehly understand thedevice, let us take a further lesson or two

We consideredthe amount of lock on each pallet, and advised the removal of the balance, because if we left the balance in we could not readily tell exactly when the tooth passed on to the i tool or a hair broach,the arc indicated by the hand _A_, Fig 72, we can deterra 75 illustrates how this experiment is conducted We apply the hair broach to the end of the fork _M_, as shown at _L_, and gentlythe hand _A_ and note the nurees, indicated by the hand as passed over before the tooth is unlocked and passes on to the impulse plane and the fork flies forward to the opposite bank Now, the quick movement of the pallet and fork may make the hand rees, as the grasp may slip on the pallet staff; but the arc indicated by the slowwill be correct

[Illustration: Fig 75]

By taking a piece of sharpened pegwood and placing the point in the slot of the fork, we can test the fork to see if the drop takes place ainst the opposite bank As we have previously stated, the drop from the pallet should not take place until the lever _al pin What the reader should ih about one and a half degrees arc to unlock, and the rerees are to be devoted to ile is only seven and a half degrees, and the jewel pin acts in accordance with the rules previously given, do not alter the pallet until you know for certain you will gain by it An observant workman will, after a little practice, be able to determine this matter

We will next take up the double roller and fork action, and also consider in rees This matter now seems of more importance, from the fact that we are desirous to impress on our readers that _there is no valid reason for adopting ten degrees of fork and roller action with the table roller, except that about this nurees of action are required to secure a reliable safety action_ With the double roller, as low as six degrees fork and pallet action can be safely eular erous factor, as will be explained further on It is perfectly co able to remedy defects, that constitute the master workman

HOW TO MEASURE THE ANGULAR MOTION OF AN ESCAPE WHEEL

[Illustration: Fig 76]

We can alsoour escape-wheel action, by letting the clasp embrace the arbor of the escape wheel, instead of the pallet staff We set the index arc as in our for 76, so that when the engaged tooth rests on the locking face of a pallet, the index hand stands at the extrerees

We next, with our pointed pegwood, start to move the fork away from the bank, as before, we look sharp and see the index handface As soon as the pallet reaches the impulse face, the hand _A_ moves rapidly forward, and if the escapement is of the club-tooth order and closely rees of angular motion before the drop takes place

[Illustration: Fig 77]