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Information, Please

From The American Horologist and Jeweler magazine, July, 1946


GMH: Can you give a combination of wheels and pinions for a Grandfather Clock with a very slow pendulum? Pendulum is about 4 or 4 1/2 feet long.

Answer: To construct a clock with a pendulum such as you wish to employ, I suggest the following train:

Main wheel to have 144 teeth, center pinion 12 leaves, center wheel 96 teeth, third pinion 12 leaves, third wheel 90 teeth, escape pinion 12 leaves and the escape wheel 25 teeth. This combination will call for a pendulum 56 3/10 inches long and will beat 1 2/10 seconds per swing of pendulum.

The following is also a combination you may use: Main wheel 120 teeth, center pinion 10 leaves, center wheel 80 teeth, 3rd pinion 10 leaves, 3rd wheel 75 teeth, escape pinion 10 leaves.
You could also use a 25-tooth escape wheel. This will employ the same length pendulum 56 3/10 inches long.

Different pendulums can be used if you follow the following formula, using the same train as called for above:

Escape Wheel teeth     Vibrations per hour    Length of pendulum
25                                 3000                           56.3 inches
26                                 3120                           51.8 inches
27                                 3240                           48.1 inches
28                                 3360                           44.7 inches
29                                 3480                           41.4 inches
30                                 3600                           39.14 inches

The only pendulum that will show seconds is the 39.14-inch pendulum.

All others will beat slower than a seconds beat, and consequently will not indicate seconds on the dial. The 56.3 inch pendulum swinging at 1.2 seconds per beat will swing 50 times per minute and the seconds bit, or dial, will have to be calibrated into 50 marks instead of the regular 60 marks. It is understood that whatever escape wheel yon may select, a special pallet will have to be made for that particular wheel.

HGE: Can you give any standard for side shake and end shake applicable to railroad watches?

Answer: In general practice, the following shakes are used:
                            End Shake          Side Shake
Center pinion      .02 mm                .015 mm
Third pinion        .02 mm                .015 mm     
Fourth pinion      .02 mm                .015 mm
Escape wheel      .02 mm                .01 mm
Pallet arbor        .015 mm              .0075 mm
Balance staff      .02 mm                .0025 mm
Barrel                 .02 mm                .015 mm
Barrel arbor       .02 mm                .015 mm
     
SHW: How can I determine the proper size drills to be used before threading a hole?

Answer: To determine the proper size tap drill for any tap, divide 1 inch by the number of threads to the inch. If your tap is not marked, you will have to count the threads. The result will be pitch, or distance from tip of one thread to the tip of the next. Then multiply the pitch by .649. This will give depth of thread. Multiplying depth of thread X 2 will give depth of two threads or the amount to be subtracted from full diameter of your tap.

RHS: I am told it is not necessary to poise a balance wheel after fitting a new staff if the wheel is well trued in round and flat. Is this true?

Answer: Regardless of how well you true the balance wheel, it should be tested for poise as you have no assurance that the wheel was in poise before you fitted the new staff. When poising the balance, the roller table is attached. In all first class shops, poising the balance is a "must." Your reputation depends on how well the watch runs after you have repaired it and no watch can keep close time in different positions unless the balance is in poise. That is your first step for building your reputation. After that, the hairspring must be perfectly centered, leveled and its development in and out from center equal in all directions. It doesn't take a customer very long to discover his watch is keeping better time after the watch has been repaired by a workman who will poise the balance and correct the hairspring.

JOC: How can a person tell the time from the bells of a ship's clock?

Answer: The striking mechanism of a ship's clock is constructed so as to strike 8 bells at 12 o'clock, 4 o'clock and 8 0 'clock. . The clock strikes each hour and half hour and one bell is added each half hour until 8 bells are reached, when the clock once more strikes one bell again, thus:

At 12 :30 strikes Ding.
At 1 :00 strikes DingDing.
At 1 :30 strikes DingDing-Ding.
At 2 :00 strikes DingDing-DingDing.
At 2 :30 strikes DingDing-DingDingDing.
At 3 :00 strikes DingDing-DingDingDingDing.
At 3 :30 strikes DingDing-DingDing- DingDing-Ding.
At 4 :00 strikes DingDing-DingDingDingDing-DingDing.
4:30 to 8 and 8 :30 to 12 o'clock, same as above.

RCB: I want to build a decimal clock showing 100 minutes to the hour. The 4th pinion is to turn 100 revolutions to 1 revolution of center wheel instead of the 60 revolutions of 4th pinion and 1 revolution of center wheel. Will you give me the combination of teeth and leaves of pinion necessary?

Answer: You can use the following combination: Center wheel to have 80 teeth, 3rd pinion 8 leaves; 3rd wheel, 70 teeth and 4th pinion 7 leaves. Or any two reductions where the ratio is 10 to 1, suitable for the space allowed between centers.

YAM: Can you give formula for determining the correct driving weight for a Graham Dead Beat escapement, having seconds beat pendulum? 

Answer: There is a formula for making these calculations which would give you the approximate weight. However, there are many factors entering the problem to be met up with, such as the size and condition of pivots, the bearings in the plate and condition of the gearing which all have something to do with the free running of the train. So, instead of going into mathematics to get results, the quickest and best way would be to suspend a container at the end of your cord and gradually fill container with buckshot or sand until you have enough power to drive the escapement. Then, continue adding weight until your escapement shows some slide. It is an easy matter then to weigh container, using the same amount of lead or cast iron for making up finished weight. The brass tube filled with lead of equal weight will then fill your requirements.

APO: Can you tell me anything about the Mozart Watch Company?

Answer: The Mozart Watch Company was founded in 1864 at Providence R. 1., and capitalized at $100,000. It was to manufacture an unusual watch having three wheels, invented by Mr. Mozart. After two years, the model was discontinued and a regular model watch designed by L.
W. Cushing of Waltham. The name of the company was changed to New York Watch Company, and the plant was destroyed by fire in 1870.

JGD: Quite often, after cleaning a watch, I find the hairspring coils have a tendency to stick together. I test for magnetism but none is apparent. Can you suggest what might be the reason for the coils sticking?

Answer: You state there is no magnetism in hairspring. Can it be possible the cleaning solution is old and also the rinse? In time they become impregnated with oil, then as the parts go thru the drying operation some of this thin film of oil is left on the hairspring, becoming sticky and causing the trouble. If your cleaning solution is in good condition, the rinses fresh, you should have no further trouble.

RMC: I have trouble setting roller jewels. I have tried shellac and other cements but somehow the roller jewel becomes loose and falls out of the roller. Can you advise what the trouble may be?

Answer: After selecting roller jewel of proper size, it should be dipped in alcohol to thoroughly clean the surface. The roller table should also be thoroughly cleaned, removing any other shellac or cement. Then when setting a new roller jewel, use new cement or shellac, not applying any more heat than is necessary to cause the cement to flow freely, as the cement will then adhere to the dry surfaces. Overheating the cement will cause it to become hard and brittle and lose its adhesive qualities.

G.AG: Which is the better and quicker method for grinding pivots to size - oilstone powder, corrundum powder or diamond powder?

Answer: We prefer to use a very fine grade of oilstone powder and oil, using an iron grinding slip for grinding the pivot to size. The oilstone powder will not imbed itself into the balance pivots, which is liable to happen if you use carborundum or diamond powder. Pivots that become charged with either of these two abrasives will soon cut the balance hole jewel and cap jewel.

RWT: I find when working on some 7-jewel Swiss watches, that shortly after oiling them the pivots appear to be dry and when testing the watch on a timing machine, it shows very irregular and spotted lines. After reoiling the watch, letting it run for some time, and testing the watch on timing machine, I find the lines are cleared up. I am curious to know if the plates are porous, absorbing the first application of oil.

Answer: The· writer has heard of some research work along this line, experimenting with porous metals. You no doubt are aware that the auto industry uses self -oiling bearings for special parts of its power unit. The metal is made of very porous material being filled with special lubrication under great pressure. Bearings thus treated will remain lubricated for a long period of time and it is possible you have run across some watch plates that have porous material. Naturally, when you clean the watch, what lubrication was in the holes was absorbed. It will require an extra application of oil in order to fill the pores in the metal.

JOC: Will you enlighten me on meantime screws, and how much regulation one can expect when turning them in or out from the balance wheel?

Answer. The balance wheel contains three kinds of screws-the large screws are the balance screws, the smaller head screws such as half head or quarter head are the timing screws, and the screws with the long thread 'and square head are the meantime screws used for final regulation.

When fitting a new hairspring, it is sometimes necessary to add a small amount of weight, such as a quarter head, or even a pair of heavy washers to bring the watch close to time, say within two minutes. It is then the meantime screws may be used to bring the watch to correct time. This is done by turning the meantime screws in or out. Turning them in will cause the watch to run fast and the reverse when turning them out.

When using the meantime screws, be very careful to turn the opposite screw an equal amount, otherwise the balance will be put out of poise, destroying position rates. The use of these meantime screws should not be abused, turning them out too far' so they may be loose or strike other parts of the watch. The following table will give you the approximate results you can expect from the average watch.

Size     Turns of screw             Sec. per hr.
18-16  1 full turn, 2 screws    3 seconds
12       1 full turn, 2 screws    2 seconds
6/0      1 full turn, 2 screws    5 seconds
18/0    1 full turn, 2 screws    5 seconds

Watches employing four meantime screws should only be turned one-half the amount shown on the chart for the same results.


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