Title: A Treatise on Staff Making and Pivoting - Containing Complete Directions for Making and Fitting New - Staffs from the Raw Material
Author: Hall, Eugene Edward
Language: English
As this book started as an ASCII text book there are no pictures available.


*** Start of this LibraryBlog Digital Book "A Treatise on Staff Making and Pivoting - Containing Complete Directions for Making and Fitting New - Staffs from the Raw Material" ***


Transcriber's notes:
Some minor typographical errors have been corrected.
The author's spelling has been retained.



                         A TREATISE

                             ON

                        STAFF MAKING

                            AND

                          PIVOTING


           CONTAINING COMPLETE DIRECTIONS FOR MAKING
                 AND FITTING NEW STAFFS FROM
                      THE RAW MATERIAL


                       EUGENE E. HALL


                 WITH NUMEROUS ILLUSTRATIONS


                          CHICAGO:
                 HAZLITT & WALKER, PUBLISHERS
                            1910



                          CONTENTS.


                          CHAPTER I.

The raw material. The gravers. The roughing out. The hardening
and tempering                                                     5

                          CHAPTER II.

Kinds of pivots. Their shape. Capillarity. The requirements of
a good pivot                                                     13

                          CHAPTER III.

The proper measurements and how obtained                         19

                          CHAPTER IV.

The gauging of holes. The side shake. The position of the graver 23

                          CHAPTER V.

The grinding and polishing. The reversal of the work. The wax
chuck                                                            29

                          CHAPTER VI.

Another wax chuck. The centering of the work                     35

                          CHAPTER VII.

The finishing of the staff. Pivoting. Making pivot drills. Hardening
drills. The drilling and fitting of new pivots                   39



STAFF MAKING AND PIVOTING.



CHAPTER I.


To produce a good balance staff requires more skill than to produce any
other turned portion of a watch, and your success will depend not alone
on your knowledge of its proper shape and measurements, nor the tools at
your command, but rather upon your skill with the graver and your success
in hardening and tempering. There are many points worthy of consideration
in the making of a balance staff that are too often neglected. 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. To have good tools and the right
ideas is one thing, and to use these tools properly and make a practical
demonstration of your theory is another.

I shall endeavor to take up every point in connection with the balance
staff, from the steel to the jewels, and their relation to the pivots,
and I believe this will then convey to the reader all the necessary
points, not only as regards staffs, but pivots also, whether applied to a
balance or a pinion staff.

It may be argued, and we often do hear material dealers advance the
theory, that to-day, with our interchangeable parts and the cheapness of
all material, it is a waste of time to make a balance staff. To the
reader who takes this view of the situation I simply want to say, kindly
follow me to the end of this paragraph, and if you are still of the same
opinion, then you are wasting your time in following me farther. For a
material dealer to advance this theory I can find some excuse; he is an
interested party, and the selling of material is his bread and butter;
but the other fellow, well I never could understand him and possibly
never shall. When we seriously consider the various styles and series in
"old model" and "new model," of only one of the leading manufacturers of
watches in this country, to say nothing of the legion of small and large
concerns who are manufacturing or have manufactured in the past, and then
think of carrying these staffs in stock, all ready for use, we then begin
to realize how utterly absurd the idea is, to say nothing of how
expensive! On the other hand, if you reside in a large city and propose
to rely on the stock of your material dealer, you will find yourself in
an embarrasing situation very often, for as likely as not the movement
requiring a new staff was made by a company that went out of business
back in the '80s, or it is a new movement, the material for which has
not yet been placed on the market. This state of affairs leads to
makeshifts, and they in turn lead to botch work. The watchmaker who does
not possess the experience or necessary qualifications to make a new
balance staff and make it in a neat and workmanlike manner, is never
certain of having exactly what is needed, and cannot hope to long retain
the confidence of his customers. In fact, he is not a watchmaker at all,
but simply an apprentice or student, even though he be working for a
salary or be his own master. There are undoubtedly many worthy members of
the trade, who are not familiar with the making of a balance staff, who
will take exceptions to this statement; but it is nevertheless true. They
may be good workmen as far as they go; they may be painstaking; but they
cannot be classed as watchmakers.

This article is intended for the benefit of that large class whose
opportunities for obtaining instruction are limited, and who are ready
and willing to learn, and for that still larger class of practical
workmen who can make a new staff in a creditable manner, but who are
always glad to read others people's ideas on any subject connected with
the trade and who are not yet too old to learn new tricks should they
find any such.

[Illustration: _Fig. 1._]

Good tools, in good condition, are the most essential requisites in
making a new staff. I would not advise any particular make of lathe, as
the most expensive lathe in the world will not produce a true staff if
the workman cannot center his work accurately and does not know how to
handle his graver, while on the other hand fine work can be done on the
simplest and cheapest lathe by a workman possessing the requisite skill.
I will take it for granted that you use an American-made lathe of some
kind, or a foreign-made lathe manufactured on American lines. It is
advisable, though not absolutely necessary, to have three gravers similar
to those illustrated in Fig. 1, A being used for turning the staff down
in the rough; B for the conical pivots and square shoulders and C for the
under-cutting. The other tools and attachments needed will be described
as I come to them in use.

The balance staff should be made of the best steel, tempered to such a
degree as to give the longest service and yet not so hard as to endanger
the breakage of the pivots. Select a piece of Stubb's steel wire, say No.
46, or a little larger than the largest part of the finished staff is to
be, and center it in a split chuck of your lathe. Be careful in selecting
your chuck that you pick one that fits the wire fairly close. The chuck
holds the work truest that comes the nearest to fitting it. If you try to
use a chuck that is too large or too small for the work, you will only
ruin the chuck for truth. Turn the wire to the form of a rough staff, as
shown in Fig. 2, leaving on a small part of the original wire, as shown
at A. After the wire is roughed out to this general form, remove from the
chuck and get ready to harden and temper it. The hardening and tempering
may be effected in various ways, and I am scarcely prepared to say which
method is the best, as there are several which give about the same
general results. One method of hardening is to smear the blank with
common yellow soap, heat it to a cherry red, and drop endwise into
linseed oil. Petroleum is preferred by some to linseed oil, but, to tell
the truth, I can see no difference in the action of linseed, petroleum or
olive oil. Be sure and have enough oil to thoroughly cool the blank, and
a deep vessel, such as a large-mouthed vial, is preferable to a saucer.
The blank will now be found too hard to work easily with the graver, and
we must therefore draw the temper down to that of fine spring steel.
Before doing this the blank should be brightened, in order that we may
see to just what color we are drawing it. The main object in using the
soap in hardening is that it may form a scale upon the blank, and if the
heating is effected gradually the soap will melt and form a practically
air-tight case around the blank. This scale, if the hardening is
carefully and properly done, will generally chip and fall off when the
blank is plunged in the oil, particularly if the oil is cool, and if it
does not fall off of its own accord, it can easily be removed by rolling
the blank upon the bench. If it does not come out clean, or if soap is
not used, it may be brightened by again inserting in the lathe and
bringing it in contact with a piece of fine emery paper or cloth.

[Illustration: _Fig. 2._]

I draw the temper in the following manner: Place some fine brass filings
in a boiling-out cup or bluing pan and lay the blank upon these filings,
holding the pan over the flame of an alcohol lamp until the blank assumes
a dark purple color, which it will reach when the heat gets to about 500°
F. This I consider the right hardness for a balance staff, as it is not
too hard to work well under the graver nor too soft for the pivots. At
this degree of hardness steel will assume an exquisite polish if properly
treated. Another method of tempering is to place the staff on a piece of
sheet iron or copper (say 1 inch wide by 4 long), having previously bent
it into a small angle, for the reception of the staff, as shown in Fig.
3. This piece of metal, when nicely fitted into a file handle, will
answer all the purposes of the bluing pan and presents quite a neat
appearance. Having placed the blank in the angle, lay on it a piece of
yellow wax about the size of a bean, and heat it over your lamp until the
wax takes fire and burns. Blow out the flame and allow the staff to cool,
and it will be found to be of about the right hardness.

[Illustration: _Fig. 3._]

We have now arrived at an important station in staff making, a junction,
we may term it, where many lines branch off from the main road. At this
particular spot is where authorities differ. I have no hesitation in
saying that at this particular point the split chuck should be removed
from the lathe head and carefully placed in the chuck box and the cement
chuck put in its place. I believe that all of the remaining work upon a
staff should be executed while it is held in a cement chuck. On the other
hand I have seen good workmen who turned and finished all the lower part
of a staff while in a split chuck, cut it off and turned and finished the
upper part in a cement chuck. All I have got to say is that they had more
confidence in the truth of their chucks than I have in mine. I have even
read of watchmakers who made the entire staff in a split chuck, but I
must confess I am somewhat curious to examine a staff made in that way,
and must have the privilege of examining it before I will admit that a
true staff can be so made.

We will suppose that the workman has a moderately true chuck, and that he
prefers to turn and finish all the lower portions in this way. Of course
the directions for using a cement chuck on the upper part of a staff are
equally applicable to the lower. Before going further I think it
advisable to consider the requirements of a pivot, but will reserve this
for another chapter.



CHAPTER II.


The chief requirements of a pivot are that it shall be round and well
polished. Avoid the burnish file at all hazards; it will not leave the
pivot round, for the pressure is unequal at various points in the
revolution. A pivot that was not perfectly round might act fairly well in
a jewel hole that was round, but unfortunately the greater proportion of
jewel holes are not as they should be, and we must therefore take every
precaution to guard against untrue pivots. Let us examine just what the
effect will be if an imperfect pivot is fitted into an unround hole
jewel, and to demonstrate its action more clearly let us exaggerate the
defects. Suppose we pick a perfectly round jewel and insert into the
opening a three-cornered piece of steel wire, in shape somewhat
resembling the taper of a triangular file. We find that this triangular
piece of steel will turn in the jewel with the same ease that the most
perfect cylindrical pivot will. Now suppose we change the jewel for one
that is out of round and repeat the experiment. We now find that the
triangular steel soon finds the hollow spots in the jewel hole and comes
to a stand-still as it is inserted in the hole. The action of a pivot
that is not true, when in contact with a jewel whose hole is out of
round, is very similar, though in a less marked degree. If the pivot
inclines toward the elliptical and the jewel hole has a like failing,
which is often the case, it is very evident that this want of truth in
both the pivot and hole is very detrimental to the good going of a watch.

[Illustration: _Fig. 4._]

[Illustration: _Fig. 5._]

There are two kinds of pivots, known respectively as straight and conical
pivots, but for the balance staff there is but one kind and that is the
conical, which is illustrated in Fig. 4. The conical pivot has at least
one advantage over the straight one, _i. e._, it can be made much smaller
than a straight pivot, as it is much stronger in proportion, owing to its
shape. All pivots have a tendency to draw the oil away from the jewels,
and particularly the conically formed variety, which develops a strong
capillary attraction. To prevent this capillary attraction of the oil,
the back-slope is formed next to the shoulder, although many persons seem
to think that this back-slope is merely added by way of ornament, to make
the pivot more graceful in appearance. It is very essential, however, for
if too much oil is applied the staff would certainly draw it away if its
thickness were not reduced, by means of the back-slope. Before leaving
the subject of capillarity let us examine the enlarged jewel in Fig. 5;
_c_ is an enlarged pivot, _b_ is the hole jewel and _a_ is the end stone.
We observe that the hole jewel on the side towards the end stone is
convex. It is so made that through capillarity the oil is retained at
the end of the pivot where it is most wanted. It is, in my opinion, very
necessary that the young watchmaker should have at least a fair
understanding of capillarity, and should understand why the end stone is
made convex and the pivot with a back slope. For this reason I will try
and make clear this point before proceeding further. We all know that it
is essential to apply oil to all surfaces coming in contact, in order to
reduce the friction as much as possible, and if the application of oil is
necessary to any part of the mechanism of a watch, that part is the
pivot. Saunier very aptly puts it thus: "A liquid is subject to the
action of three forces: gravity, adhesion (the mutual attraction between
the liquid and the substance of the vessel containing it), and cohesion
(the attractive force existing among the molecules of the liquid and
opposing the subdivision of the mass.)"

We all know that if we place a small drop of oil upon a piece of flat
glass or steel and then invert the same the oil will cling to the glass,
owing to the adhesion of the particles; if we then add a little more to
the drop and again invert, it will still cling, although the drop may be
elongated to a certain degree. This is owing to the cohesion of the
molecules of the oil, which refuse to be separated from one another. If,
however, we again add to the drop of oil and invert the plate the drop
will elongate and finally part, one portion dropping while the other
portion clings to the main body of the liquid. The fall of the drop is
occasioned by gravity overcoming the cohesion of the molecules. Now take
a perfectly clean and polished needle and place a drop of oil upon its
point and we will see that the oil very rapidly ascends towards the
thicker portion of the needle. Now if we heat and hammer out the point of
the needle into the form of a small drill and repeat the operation we
find that the oil no longer ascends. It rises from the point to the
extreme width of the drill portion, but refuses to go beyond. It clings
to that portion of the needle which would correspond to the ridge just
back of the slope in a conical pivot. Water, oil, etc., when placed in a
clean wine glass, do not exhibit a perfectly level surface, but raise at
the edges as shown at _a_ in Fig. 6. If a tube is now inserted, we find
that the liquid not only rises around the outside of the tube and the
edges of the vessel, but also rises in the tube far beyond its mean
level, as shown at _b_. These various effects are caused by one of the
forces above described, _i. e._, the adhesion, or mutual attraction
existing between the liquid and the substance of the vessel and rod. The
word capillarity is of Latin derivation, and signifies hair-like
slenderness. The smaller the tube, or the nearer the edges of a vessel
are brought together, the higher in proportion will the liquid rise above
the level. An ascent of a liquid, due to capillarity, also takes place,
where the liquid is placed between two separate bodies, as oil placed
between two pieces of flat glass. If the plates are parallel to one
another and perpendicular to the surface of the liquid it will ascend to
the same height between the plates, as shown at _c_ in Fig. 6. If the
plates were united at the back like a book and spread somewhat at the
front, the oil would ascend the higher as the two sides approach one
another, as shown at _d_, Fig. 6. If a drop is placed somewhat away from
the intersecting point, of the glasses, as shown at _m_ it will, if not
too far away, gradually work its way to the junction, providing the
glasses are level. If, however, the glasses are inclined to a certain
extent, the drop will remain stationary, since it is drawn in one
direction by gravity and in the other by capillarity. When a drop of oil
is placed between two surfaces, both of which are convex, or one convex
and the other plain, as shown at _g_, it will collect at the point _n_,
at which the surfaces nearest approach one another. We now see very
clearly why the hole jewel is made convex on the side towards the
end-stone and concave on the side towards the pivot.

[Illustration: _Fig. 6._]

Particular pains should be taken to polish those portions of the pivots
which actually enter the jewel hole and to see that all marks of the
graver be thoroughly removed, because if any grooves, no matter how
small, are left, they act as minute capillary tubes to convey the oil.

If the hole jewel be of the proper shape, the end-stone not too far from
the hole jewel and too much oil is not applied at one time, the oil will
not spread nor run down the staff, but a small portion will be retained
at the acting surface of pivot and jewel, and this supply will be
gradually fed to these parts from the reservoir between the jewel and
end-stone, by the action of capillarity.

Having examined into the requirements of the pivot and its jewel and
having gained an insight into what their forms should be, we are the
better able to perform that portion of the work in an intelligent
manner.



CHAPTER III.


Our wire has been roughed out into the form of a staff, has been hardened
and the temper drawn down to the requisite hardness and we are now ready
to proceed with our work. As I said before, we have now arrived at a
point where many authorities differ, _i. e._, as to whether the finishing
of the staff proper, should be performed while the work is held in the
chuck, or whether a wax chuck be substituted. We will take it for granted
that you have a true chuck and that you prefer to finish all the lower
portion of the staff while held in the chuck.

Before we proceed with our work it will be necessary for us to make some
accurate measurements, as we cannot afford to do any guess work by
measuring by means of the old staff. I have used a number of different
kinds of calipers and measuring instruments for determining the various
measurements for a balance staff, but have met with more success with a
very simple little tool which I made myself from drawings and description
published some years ago in THE AMERICAN JEWELER. This simple little tool
is shown in Fig. 7, and has been of great service to me. It consists of a
brass sleeve A, with a projection at one end as shown at B. This sleeve
is threaded, and into it is fitted the screw part C, which terminates in
a pivot D, which is small enough to enter the smallest jewel. The sleeve
I made from a solid piece of brass, turning it down in my lathe and
finishing the projection by means of a file. The hole was then drilled
and threaded with a standard thread. The screw part C, I made of steel
and polished carefully.

[Illustration: _Fig. 7._]

To ascertain the proper height for the roller, place it upon the tool,
allowing it to rest upon the leg B, and set the pivot D in the foot
jewel. Now adjust, by means of the screw C until the roller is in its
proper position in relation to the lever fork. This may be understood
better by consulting Fig. 8, where A is the gauge, C is the roller, E is
the lever, F is the plate and G is the potance.

[Illustration: _Fig. 8._]

Now in order to locate the proper place to cut the seat for the roller,
remove it from the foot of the gauge and apply the gauge to the work as
shown in Fig. 9. The foot of the gauge resting against the end of the
pivot, the taper end of the gauge will locate accurately the position of
the roller seat. In order to locate the proper position for the seat for
the balance, proceed the same as for the roller, except that the foot of
the gauge is lowered until it is brought sufficiently below the plate to
allow of the proper clearance as indicated by the dotted lines at H. Now
apply the gauge to the new staff, as shown in Fig. 10, and the taper end
will locate the exact position for the balance seat.

[Illustration: _Fig. 9._]

[Illustration: _Fig. 10._]

As previously stated, I have taken it for granted that you preferred to
finish all the lower portion of the staff while the work was held in the
chuck. I have assumed that you prefer to work in this way because I have
noted the fact that nine watchmakers out of every ten start with, and
first finish up, the lower portion of the staff. Where this method of
working originated I do not know, but it always has the appearance to me
of "placing the cart before the horse." I do not pretend to say that a
true staff cannot be made in this way, but it certainly is not the most
convenient nor advisable. We all know that the heaviest part of the staff
is from the roller seat to the end of the top pivot. Now it seems to me
that it is the most natural thing in the world for a mechanic to desire
to turn the greater bulk of his work before reversing it. Now if the
workman has been educated to turn indifferently with right or left hand,
it may make little difference, as far as the actual turning is concerned,
whether he starts to work at the upper or lower end of the staff, but
unfortunately there are few among us who are so skilled as to use the
graver with equal facility with either hand, and it is therefore an
advantage to start with the upper end, as you can thus finish a greater
portion of the work more readily. You can readily see that when you come
to reverse your staff and use the wax chuck, that by starting at the top
of staff your wax has a much larger surface of metal to cling to, and
again the shape of the balance seat is such as to secure the work firmly
in the wax, while if the reverse method is employed, the larger portion
of the balance seat is exposed and the staff is more liable to loosen
from the motion of the lathe and pressure of the graver and polishers.



CHAPTER IV.


By the aid of the pinion calipers and the old staff, the diameter of the
roller seat and the balance and hair-spring collet seats may be readily
taken, but it is perhaps better to gauge the holes, as the old staff may
not have been perfect in this respect. 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. 11, is, however, open
to one objection in the measurement of pivots, and that is that it may be
pressed down at one time with greater force than at another, and
consequently will show a variation in two measurements of the same pivot.
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 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. 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. Of course it is
understood that side shakes do not increase in proportion according as
the pivot increases in size, for if they did a six-inch shaft would
require at this rate a side shake of 1/2 inch, or 1/4 inch on each side,
which would be ridiculously out of all proportion, as the 1/64 of an inch
would be ample under any circumstances. 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. We must leave sufficient side shake, however,
on the smallest pivot and jewel for the globules of the oil to move
freely, and experiments have shown conclusively that 1/2500 of an inch or
1/5000 on each side of the pivot, is as little space as it is desirable
to leave for that purpose, as the globules of the best chronometer oil
will refuse to enter spaces that are very much more minute. But to return
to our pivot gauge.

[Illustration: _Fig. 11._]

[Illustration: _Fig. 12._]

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,
however, you prefer to make the measurement still more accurate, you can
do so by dipping the broach into rouge before slipping on the jewel and
then remove the jewel and the place which is occupied on the broach can
be plainly discerned and the exact measurement taken and an allowance of
1/2500 of an inch made for the side shake. Another method, and one which
is particularly applicable to Swiss watches, where the jewel is burnished
into the cock or plate, is to first slip on to the broach a small flat
piece of cork and as the broach enters the jewel the cork is forced
farther on to the broach, and when the jewel is removed it marks the
place on the broach which its inner side occupied, and the measurement
can then be taken with the gauge. If care is used in the selection of a
broach, that it be as nearly perfect in round and taper as possible, by a
little experiment you can soon ascertain just what part of the length of
the broach corresponds to one degree on the gauge and by a repetition of
the experiment the broach can then be divided accurately, by very minute
rings turned with a fine-pointed graver, into sections, each representing
one degree, or 1/2500 of an inch, and the measurement will thus be
simplified greatly.

[Illustration: _Fig. 13._]

As before stated, much depends upon the condition of your gravers and the
manner of using them. It is of the utmost importance that they be kept
sharp, and as soon as they begin to show the slightest sign of losing
their keenness, you should sharpen them. The proper shape for balance
pivots was shown in Fig. 4. Now let us examine into the best positions
for holding the gravers. In Fig. 13 two ways of holding the graver are
shown, _A_ representing the right and _B_ representing the wrong way. If
the graver is applied to the work as shown at _A_, it will cut a clean
shaving, while if applied as shown at _B_ it will simply scrape the side
of the pivot and ruin the point of the graver without materially
forwarding the work. Again, the holding of the graver as indicated at _A_
has its advantages, because the force of the cut is towards the hand
holding it, and should it catch from any cause the jar of the obstruction
will be conveyed immediately to the hand, and it will naturally give and
no harm will be done. If, on the other hand, the graver should meet with
an obstruction while held in the position indicated at _B_, the force of
the cut will be in the direction of the arrow, downward and toward the
rest, and the rest being unlike the hand, or rather being rigid, it
cannot give, and the result is that the work, or graver, or both, are
ruined. In Fig. 14 two other methods of holding the graver are shown. The
general roughing out of a staff should be done with the graver held about
as shown at _A_, Fig. 13; but in finishing, the graver should be held so
that the cut is made diagonally, as indicated at _A_, Fig. 14. It is
rather dificult to explain in print just how the graver should be held,
but a little experiment will suffice to teach the proper position. The
best indication that a graver is doing its work properly, is the fact
that the chips come away in long spiral coils. Aim to see how light a cut
you can make rather than how heavy. Never use force in removing the
material, but depend entirely upon the keenness of the cutting edges.
Never use the point of the graver, except where you are compelled to, but
rather use the right or left hand cutting edges. By following out this
rule you will find that your work, when left by the graver, requires
little or no finishing up, except at the pivots. At _B_, Fig. 14, is
shown the correct manner of applying the graver when turning a pivot.
Hold the graver nearly on a line with the axis of the lathe and catching
a chip at the extreme end of the pivot with the back edge of the graver,
push slightly forward and at the same time roll the graver towards you
and it will give the pivot the desired conical form. 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.

[Illustration: _Fig. 14._]



CHAPTER V.


In chapter IV I called attention to the right and wrong way of holding
the graver while using the extreme point, and also the correct manner of
applying the graver in turning conical pivots. I also called attention to
the fact that it was well to only use the point of the graver where
positively necessary, as in the back slope of the pivot, etc. In turning
the seat for the balance, as indicated at A, Fig. 15, the graver A, Fig.
1, or a similar one as shown at B, Fig. 15, should be used. The slope at
C should now be turned. In turning the pivot and seat for the roller, you
should leave them slightly larger than required, to allow for the
grinding and polishing which is to follow. No definite amount can be left
for this purpose, because the amount left for polishing depends entirely
on how smoothly your turning has been done. If it has been done
indifferently, you may have to allow considerable for grinding and
polishing before all the graver marks are removed, while, on the
contrary, if the work has been performed with care, very little will have
to be removed. Avoid the use of the pivot file by performing your work
properly to start with.

[Illustration: _Fig. 15._]

[Illustration: _Fig. 16._]

For grinding, bell-metal or soft iron slips are desirable, and the
grinding is effected by means of oil stone powder and oil. Two slips of
metal similar in shape to A and B, Fig. 16, are easily made, and will be
found very useful. A is for square pivots, etc., while B is used for
conical pivots. These slips should be dressed with a dead smooth file,
the filing to be done crosswise, to hold the oil stone powder and oil.
During the operation of grinding, the lathe should be run at a high speed
and the slips applied to the work lightly, squarely and carefully. The
polishing is effected by means of diamantine and alcohol. After the work
is brought to a smooth gray surface, slips of boxwood of the shape shown
in Fig. 16 should be substituted for the metal slips. Oil stone slips are
sometimes used in lieu of metal ones, but they soon get out of shape and
are troublesome to care for on this account. All things considered, there
is nothing better for polishing than a slip or file made of agate, say
one inch long, one-quarter inch wide and one-eighth inch thick. A slip of
this kind can be obtained from any lapidary, and after grinding with
emery and water until the surface has a very fine grain, it should be
mounted by fastening with cement into a brass socket and this is then
inserted into a small wooden handle, as shown in Fig. 17. The agate slip
should be ground to about the shape of B, Fig. 16, so that one side can
be used for square corners and the other for conical pivots. The final
polish can soon be imparted by means of a small boxwood slip, or
flattened peg-wood, and diamantine and alcohol. Never try to bring out
the final polish until you are satisfied that all graver marks have been
ground out, otherwise you will simply have to go all over the work again.

[Illustration: _Fig. 17._]

When the staff is finished from the lower pivot to the seat of the
balance, the upper part should be roughed out nearly to size and then cut
off preparatory to finishing the top part.

Attention was previously called to the fact that the majority of
watchmakers prefer to finish all the lower portion of the staff first,
notwithstanding the fact that there are numerous advantages to be gained
by proceeding to first finish up the upper portion. We have now reached
the point where the wax chuck must be used, and perhaps these advantages
may be now more clearly defined. In order that the two procedures may be
more distinctly shown, illustrations of both methods are here given.
Fig. 18 shows the popular method, the lower portion of the staff being
all completed and fastened by means of wax, in the wax chuck. Fig. 19
shows the opposite course of procedure. In both illustrations the lines
indicate the amount of wax applied to hold the work. It will be noted
that in Fig. 18 the hub of the staff is enclosed in the wax very much as
a cork is fitted into a bottle, while in Fig. 19 the hub is reversed,
just as a cork would appear were the larger portion within the bottle and
the smaller portion protruding through the neck. A study of the diagram
will readily show that in Fig. 19 the staff is held more rigidly in place
and that a greater bulk of the work is enclosed in the wax than in Fig.
18, although there is less wax used in the former than in the latter.

[Illustration: _Fig. 18._]

[Illustration: _Fig. 19._]

Before proceeding to set the staff in the wax, it is necessary to make
some measurements to determine its full length. Remove both cap jewels
and screw the balance cock in place. Examine the cock and see if it has
at any time been bent up or down or punched to raise or lower it. If so,
rectify the error by straightening it and then put it in place. Now with
a degree gauge, or calipers, proceed to take the distance between the
outer surfaces of the hole jewels and shorten the staff to the required
length. Do not remove too much, but leave the staff a little long rather
than cut it too short, as the length can be shortened later.

[Illustration: _Fig. 20._]

[Illustration: _Fig. 21._]

A very handy tool for the purpose of making these length measurements can
be constructed by adding a stop screw to the common double calipers as
shown in Fig. 20. The improvement consists in the fact that they can be
opened to remove from the work and closed again at exactly the same
place, so that an accurate measurement can be made. The all-important
point in the use of wax chucks is to get a perfect center. If you are not
careful you are liable to leave a small projection in the center as shown
at A, Fig. 21. The ordinary wax chuck cannot be unscrewed from the
spindle and restored to its proper place again with anything like a
certainty of its being exactly true, and if you insist on doing this
there is no remedy left but finding a new center each time. It will be
found more satisfactory and economical in the long run to have a
permanent chuck for a wax chuck and you will then have no necessity for
removing the brass chuck.

The center, or cone for the reception of the pivot, should be turned out
with the graver at an angle of about 60° and such a graver as is shown at
B, Fig. 1, will answer admirably for this purpose. After you have
carefully centered your wax chuck, place a small alcohol lamp under the
chuck and heat it until the wax will just become fluid and yet not be hot
enough to burn the wax. Revolve the lathe slowly and insert the staff so
that the pivot rests squarely and firmly in the center. Now re-heat the
chuck carefully in order that the wax may adhere firmly to the staff,
keeping the lathe revolving meanwhile, but not so fast that the wax will
be drawn from the center, and at the same time apply the forefinger to
the end of the staff, as shown in Figs. 18 and 19, and gently press it
squarely into place in the wax chuck. The lines in Figs. 18 and 19
designate about the right amount of wax after the work is ready, but it
is well to add a little more than is shown in those figures, and you
should be careful to keep the wax of equal bulk all around, or when it
cools it will have a tendency to draw the staff to one side. Now remove
the lamp and keep the lathe revolving until the wax is quite cool, when
it should be removed, by means of a graver, down to the dimensions
designated by the lines in Figs. 18 and 19. When this is accomplished
re-heat a little, but only enough to make it soft, but not liquid, and
placing a sharpened peg-wood on the tool rest proceed to the final truing
up, by resting the pointed end against the hub.



CHAPTER VI.


I have described above one of the methods in vogue for holding a staff by
means of wax. It is the common method employed by most watch repairers,
the popular method so to speak. The method which I am now about to
describe may seem awkward at first to those who have not practiced it,
but once you have fairly tried it, you will never be contented to work in
any other way.

The first requisite is a true taper chuck; and it is well to purchase an
extra one to be used solely for this purpose, so that you will be
prepared at all times for staff work. Select a good steel taper, and
having placed your chuck in the lathe, see if your taper fits well by
inserting it in the chuck while running slowly. If it fits well, it will
be marked almost throughout its length. Insert again in the chuck, and
with a few light taps of the hammer set it firmly in place, so that you
know that there is no danger of its working loose. The taper will then
project about three-quarters of an inch from the face of the chuck. By
means of a sharp graver, make the face of the taper smooth and straight,
and cut off the taper end. Now mark a point on the taper about one-fourth
of an inch from the end, and proceed to turn down the diameter from this
point to the end, leaving that portion of the taper about two-thirds of
its original diameter, and finish with a nice square shoulder. Now with
a long-pointed sharp graver proceed to cut a nice V-shaped center with an
angle of about 60°. When you have proceeded thus far you will find that
you have an implement resembling that shown in Fig. 22.

[Illustration: _Fig. 22._]

Care must be taken that the center is quite true, and that no projection
is left like that illustrated in Fig. 21, no matter how minute it may be.
Now examine the center by the aid of a strong glass, and after you are
satisfied with its appearance proceed to test it. Take a large sized pin
with a good point, and placing the point in the center, maintain it in
position by pressing upon the head, and while revolving the lathe slowly
proceed to examine by means of your glass. If the center is a good one
there will be no perceptible vibration of the pin.

Now procure a piece of small brass tubing with an internal diameter a
little less than that of the turned down portion of your taper. If the
brass tubing cannot be procured readily, you can substitute a piece of
brass wire a little larger than the taper, and by means of a drill a
little smaller in diameter than the turned down portion you can readily
make a small tube about one-half inch long. Now by means of a broach
proceed to open the tube to a point one-quarter inch from one end, and
carefully fit it on the turned down portion of your taper. After fitting
tightly to the shoulder of the taper, proceed to turn out the other end
until it will take in the hub of your staff easily and leave a little
room to spare. Now turn your tube down in length until a little of the
hub is exposed either way you put the staff in. Turn the outside of the
tube smooth and to correspond with the outline of the taper, so you will
have a nice looking job when completed. Just below where the hub will
come drill a small hole in the tube and remove all burr, both inside and
out, that may have been made in drilling, so that the shellac or wax will
not adhere to it. This little hole acts as an outlet for the air in the
tube; and as the hot shellac enters at the end of the tube the air is
expelled through this vent. It also helps to hold the cement firmly in
place. Now try your staff in the tube again, and be sure that it is quite
free, and that you will be able to work on the portions of it above and
below the hub, according as one end or the other is inserted.

You are now ready to insert your staff and proceed with your work. Hold
your shellac in the flame of your lamp a moment until it is quite liquid,
and then smear both the inside and outside of the tube with it. Heat the
shell or tube gently by means of the lamp, keeping the lathe revolving
slowly all the while, and taking the staff in your tweezers proceed to
insert it carefully into the tube. Press firmly back, making sure that it
has reached the bottom of the V-shaped center. Pack the cement well in
around the staff, and while centering remove the lamp and allow the
whole to cool, keeping the whole revolving until quite cool. Now remove
the superfluous cement by means of the graver, and heating the tube again
slightly, proceed to center exactly by means of a pointed peg-wood,
resting on your T rest to steady it. Turn slowly in the lathe and examine
with glass to see that it is quite true. Your completed instrument will
resemble Fig. 23.

[Illustration: _Fig. 23._]

The advantage of the device is that your center is always ready, and all
you have to do is to insert your chuck in the lathe, warm it, and you are
ready to insert your staff and proceed to work. As I said in the first
place, it is well to employ a taper chuck exclusively for this work, and
not attempt to use it for any other, for if you try to remove your taper
and replace it again, you will surely find that your work is out of
center, and you will be compelled to remove the brass shell and find a
new center each time you use it. You can avoid all this trouble, however,
by purchasing an extra chuck and devoting it exclusively to wax work. Of
course, the brass shell can be removed and placed in position again
without in any way affecting the truth of the center, and any number,
shape and size of shells can be made to fit the one taper, and these
shells will be found very useful for holding a variety of work, aside
from balance staffs.



CHAPTER VII.


The two popular methods of holding a balance staff in wax have been
described and illustrated; the reader may take his choice. The turning
and finishing of the other end of the staff is performed as previously
described. That portion on which the hair-spring collet goes should be
turned to nearly the proper size, making due allowance for the grinding
and polishing that is to come. The balance seat should be slightly
undercut, so that the balance can be driven on tightly and all riveting
dispensed with. The size for the pivot can be determined from its jewel,
as previously described. Finish the ends of the pivots flat and round the
corners off slightly; and right here comes a point worthy of
consideration in all watch work. Leave no absolutely square corners in
any of your work, but round them off very slightly. This may seem a very
little thing, but it is one of the small things that go to make up
first-class work. You can judge pretty accurately of a watchmaker by the
corners he leaves on his work, as well as by the appearance of his
gravers and screw-drivers.

When your staff is completed and nicely polished, remove from the wax and
boil in alcohol to clean, and when dried it is ready for the balance.
Great care must be exercised in removing the balance from the old staff,
especially if it be a compensation balance, that you do not distort it
any way. If the balance has been riveted on extra care will have to be
exercised. The riveting may be cut by means of a graver, or a hollow
drill made from Stubb's steel wire. The recess in the drill should just
fit over the shoulder left for the reception of the hair-spring collet.
The edge of the hollow drill has small teeth formed upon it similar to a
fine file, and will cut quite rapidly.

After removing the balance, if it appears to be sprung in the arms, the
result of removal or previous bad treatment, proceed to bend them
straight, and then to true up the rim carefully, and stake on with a flat
end punch. Now put on your roller and drive it down to the hub and see
that the roller is free from the fork. See that jewel pin reaches fork
properly and that the guard pin also reaches the roller. See that your
balance is free from the plate and the bridge. If the balance is true and
all right, you are ready to put on your hair-spring. See that it is in
beat. It is well to make a mark on the balance before taking off the old
staff, showing positions of hair-spring stud and jewel pin.

Three-quarter plate English lever and Swiss lever balance staffs differ
only in detail, except that they are sprung under balances. The general
operations for making, however, are similar to those described.

I have not described the method of poising the balance for two reasons;
first, the mere poising of a balance for a cheap movement is so simple
that it needs no explanation; and second, to describe the poising of the
balance of a fine watch is a lengthy task, and can hardly be included
under the heading of staffing and pivoting. The ground has been
thoroughly and conscientiously covered by Mr. J. L. Finn, in a little
volume entitled Poising the Balance,[A] and I would advise all
watchmakers, both young and old, to read what he has to say.

Good pivoting is an art in itself, and although there are many who
undertake to do this work, there are but few who can pivot a staff in
such a manner that it will bear close inspection under the glass. We
often hear watchmakers brag of the secrets they possess for hardening
pivot drills, but I fancy they would be somewhat surprised if they
traveled around a little, to find how many watchmakers harden their
drills in exactly the same way that they do. The great secret, so-called,
of making good drills, is to first secure good steel, and then use care
to see that you do not burn it in the subsequent operations. The fewer
times the steel is heated the better. My experience teaches me that you
can do no better than to select some nice pieces of Stubb's steel for
your pivot drills. Many watchmakers make their drills from sewing
needles, say No. 3 or 4, sharps. The steel in these needles is usually of
good quality, but the great drawback is that a drill made from a needle
will not resist any great pressure, and is liable to break just at the
time that you have arrived at the most important point. If 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. 24. The
conical form is given to the drill for exactly the same reason that it is
given to the balance pivots, because it gives additional strength. Heat
to a very pale red for about one-half inch from the end, and then spread
the point, as shown at _B_, Fig. 24, by a slight blow of the hammer. We
are now ready to temper our drill, and we must exercise a little care
that the steel is not burnt and that the drill is not bent or warped when
hardening. The flame of the alcohol lamp should be reduced as small as
possible, or otherwise the steel may become overheated and lose all its
good qualities. If needles are used for making drills there is a great
liability of their warping when hardening, but when a larger piece of
wire is used there is not much danger, if care is exercised in
introducing the drill that it goes into the compound straight and point
foremost. If a needle is used, it is well to construct a shield for it,
to be used when heating and hardening. This shield can be made from a
small piece of metal tubing, broached out to fit loosely over the shank
and point of the drill. The drill is introduced into this shield as shown
in Fig. 25, and a little soap may be introduced into the end _a_ before
plunging. Various hardening devices are used, but in my experience
beeswax or sealing wax will be found as good as any. Heat the drill (or
if a needle, the drill and shield both), to a pale red and plunge
straight into the wax. In the latter case, where the shield is used, the
shield, on striking the wax, will run up the shank of the drill, allowing
the point to pierce the wax. Some watchmakers introduce the extreme point
of the drill into mercury first and then plunge into the wax. This
hardens the extreme point of the drill very hard, so hard, in fact, that
it will penetrate the hardest steel, but care must be exercised with such
a drill because the mercury makes it not only very hard but very brittle.
_C_, Fig. 24, shows a drill after it has been finished on the Arkansas
stone. This shape of drill will withstand the pressure necessary to drill
into hard steel. Many watchmakers reduce the temper of every staff before
drilling. This, I think, is quite unnecessary. There are very few cases
in which it is necessary to reduce the temper of the staff, and even then
it should only be reduced as far as it is to be drilled, and then not in
excess of a good spring temper.

[Illustration: _Fig. 24._]

[Illustration: _Fig. 25._]

The centering of a staff in wax has been thoroughly described and in
pivoting the proceeding is the same as in staffing. After accurately
centering your work, make a small cut in the center for the reception of
the drill and make this mark deep enough to take the entire cutting head
of the drill. Keep the drill firmly pressed into this center and kept wet
constantly with turpentine. Do not revolve the work all one way, but give
the lathe an alternating motion. At first give but a third or a half
revolution each way, until the drill begins to bite into the staff, when
you can then safely give it a full revolution each way. Care must be
exercised, however, not to give the work too rapid a motion, for if you
do the friction is apt to draw down the temper of your drill. Many
watchmakers find that their drills cut well for a certain distance and
then refuse to work altogether, and one of the chief reasons is that they
are in too great a hurry with their drilling.

If you find it absolutely necessary to reduce the hardness of your staff
before drilling, do so by drilling a hole in the end of a small piece of
copper wire that will just fit over the part to be softened, and apply
the heat to this copper wire, say one-fourth of an inch from the staff.
The heat will run down the copper wire and heat the staff just where you
wish to draw the temper. Be careful and do not draw the temper too much,
nor let it extend down the staff too far.

The plug for the new pivot should be carefully made, perfectly round,
with a very little taper, and should be draw-filed before being driven
in. Some workmen dip the plug in acid before driving in, as they declare
that the pivot is less liable to be loosened while turning, if so
treated. 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.

The turning up of a new pivot does not differ in any way from the
instructions given for turning pivots on a new staff. With a little care
both in turning and finishing, a new pivot can be put in so nicely that
only the initiated can tell it, and then only with the aid of a strong
glass.

In pivoting cylinders there is some danger of breaking them. To avoid
this, select a piece of joint wire, the opening of which is slightly
larger than the diameter of the cylinder at the lower end, and cut off a
piece the length of the cylinder proper, leaving the pivot projecting.
Now fill the cylinder with lathe wax, and while the wax is warm, slip on
the joint wire. You can now proceed to true up the pivot in the usual
manner, and when the wax is quite cold, proceed to turn and polish the
pivot before removing from the lathe. If the joint wire is properly
cemented on the cylinder, it is almost impossible to break it. After all
the work is done, the wax can be dissolved in alcohol. In pivoting
pinions to cylinder escape-wheels and third wheels, it is not necessary
to remove the wheels, but great care should be used in handling. In the
latter case use plenty of wax. Do all your centering by the outside of
the pinion. Perfect centering and sharp tools are requisite to good
pivoting. Do not try to rush your work, especially while drilling.
Proceed deliberately with your work and aim to restore the watch to the
condition it was in originally, and you will find staffing and pivoting
is not half as hard as some workmen would have you believe.

[Footnote A: POISING THE BALANCE, by J. L. Finn, Geo. K. Hazlitt & Co.,
publishers, Chicago.]





*** End of this LibraryBlog Digital Book "A Treatise on Staff Making and Pivoting - Containing Complete Directions for Making and Fitting New - Staffs from the Raw Material" ***

Copyright 2023 LibraryBlog. All rights reserved.