Part 1 (1/2)

Watch and Clock Escapements

by Anony the achievey were the three serials devoted to the lever, cylinder and chronohly valued were these serials when published that on the completion of each ere importuned to republish it in book form, but we deemed it advisable to postpone such publication until the completion of all three, in order that the volume should be a coy The recent coave us the opportunity to republish in book form, and the present volume is the result We present it to the trade and students of horology happy in the knowledge that its contents have already received their approval An interesting addition to the book is the illustrated story of the escapements, from the first crude conceptions to their present perfection

WATCH AND CLOCK ESCAPEMENTS

CHAPTER I

THE DETACHED LEVER ESCAPEMENT

In this treatise we do not propose to go into the history of this escapein and evolution, but shall confine ourselves strictly to the designing and construction as e full instructions for drawing an escapement of this kind to the best proportions The work-board about 15” by 18” will be quite large enough The necessary drawing-instruments are a T-square with 15” blade; a scale of inches divided into decimal parts; two pairs dividers with pen and pencil points--one pair of these dividers to be 5” and the other 6”; one ruling pen Other instruments can be added as the workman finds he needs them

Those enumerated above, however, will be all that are absolutely necessary

[Illustration: Fig 1]

We shall, in addition, need an arc of degrees, which we can best make for ourselves To construct one, we procure a piece of No 24 brass, about 5” long by 1” wide We show such a piece of brass at _A_, Fig 1 On this piece of brass eep two arcs with a pair of dividers set at precisely 5”, as shown (reduced) at _a a_ and _b b_ On these arcs we set off the space held in our dividers--that is 5”--as shown at the short radial lines at each end of the two arcs Now it is a well-known fact that the space erees of the arcs _a a_ and _b b_, or one-sixth of the entire circle; consequently, we divide the arcs _a a_ and _b b_ into sixty equal parts, to represent degrees, and at one end of these arcs we halve five spaces so we can get at half degrees

[Illustration: Fig 2]

Before we take up the details of drawing an escaperees,” as this see difficult to understand byto draw parts of watches to scale At Fig 2 we show several short arcs of fifteen degrees, all having the coree must be a specific space, like an inch or a foot Now the first thing in learning to draw an escaperee depends entirely on the radius of the arc we e 2 Here the arcs _c_, _d_, _e_ and _f_ are all fifteen degrees, although the linear extent of the degree on the arc _c_ is twice that of the degree on the arc _f_ When we speak of a degree in connection with a circle we mean the one-three-hundred-and-sixtieth part of the periphery of such a circle In dividing the arcs _a a_ and _b b_ we first divide them into six spaces, as shown, and each of these spaces into ten ree spaces, as shown at _h_ We should be very careful about1, as the accuracy of our drawings depends a great deal on the perfection of the division on the scale _A_ In connection with such a fixed scale of degrees as is shown at Fig 1, a pair of sree space, is very convenient

MAKING A PAIR OF DIVIDERS

[Illustration: Fig 3]

To make such a pair of small dividers, take a piece of hard sheet brass about 1/20” thick, ” wide, 1” long, and shape it as shown at Fig

3 It should be explained, the part cut from the sheet brass is shown below the dotted line _k_, the portion above (_C_) being a round handle turned from hard wood or ivory The slot _l_ is sawn in, and two holes drilled in the end to insert the needle points _i i_ In e to have the needle points coree spaces on the arcs _a a_ and _b b_ We then put the s _j_, set the needle points _i i_ to exactly agree with the degree spaces As soon as the points _i i_ are set correctly, _j_ should be soft soldered fast

The degree spaces on _A_ are set off with these dividers and the spaces on _A_ very carefully marked The upper and outer arc _a a_ should have the spaces cut with a graver line, while the lower one, _b b_ is best permanently marked with a carefully-made prick punch After the arc _a a_ is divided, the brass plate _A_ is cut back to this arc so the divisions we have justtwo arcs on the plate _A_ is, if we desire to get at the nurees contained in any arc of a 5” radius we lay the scale _A_ so the edge agrees with the arc _a a_, and read off the nu dividers we employ the dotted spaces on the arc _b b_

DELINEATING AN ESCAPE WHEEL

[Illustration: Fig 4]

We will now proceed to delineate an escape wheel for a detached lever

We place a piece of good drawing-paper on our drawing-board and provide ourselves with a very hard (HHH) drawing-pencil and a bottle of liquid India ink After placing our paper on the board, we draith the aid of our T-square, a line through the center of the paper, as shown at _in of the paper we establish the point _p_ and sweep the circle _n n_ with a radius of 5” We have said nothing about stretching our paper on the drawing-board; still, carefully-stretched paper is an i We shall subsequently give directions for properly stretching paper, but for the present ill suppose the paper we are using is nicely tacked to the face of the drawing-board with the smallest tacks we can procure The paper should not co-board, so as to interfere with the head of the T-square We are now ready to co our escape wheel and a set of pallets to match

The simplest form of the detached lever escapement in use is the one known as the ”ratchet-tooth lever escapelish lever watches This forives excellent results ell eneral use fro and capable of resisting careless usage as the club-tooth escape wheel

It will be our aieneral principles, rather than to give specific instructions for doing ”one thing one way” The ratchet-tooth lever escapements of later dates have alree lever-and-pallet-action plan; that is, the fork and pallets were intended to act through this arc Soer arcs--sorees