Pre inspection of functions
I start off by giving the watch a full wind and hold it up to my ear and just listen. The sounds coming from the movement often give me clues to what might be going on inside the watch and help with the inspection process. I then put your watch onto my timing machine to see what kind of timing rate, (how well the watch keeps time) and amplitude, (how well the power is transferred from the mainspring to the balance wheel) your watch has. This gives me the overall health of the watch movement and gives me clues for what I need to look for in the inspection.
Pre disassembly inspection
If any issues came up in the initial inspection while the watch was together, I do a partial disassembly to look for the issue I detected. Sometimes this will reveal a damaged part that will need to be replaced but often the issue is just dirt and gunk buildup that will be rectified when the watch is cleaned. If a part is defective, we will continue the inspection under high magnification to look any possible other issues like broken or cracked jewels, broken pivots etc, source the part & cost and relay this information to you along with a picture documentation. I find this keeps the overall time for service down to a minimum by being able to get any needed parts ordered before your actual scheduled service date. If you decide not to proceed because of the additional costs, I will reassemble the watch and return it to you. You will be billed a $75.00 inspection fee.
Full disassembly and microscope inspection
If no faults were detected in the initial pre inspection your watch will fully disassembled on your scheduled service date. Before a wheel is removed, I check the end shake and side shake. This refers to the amount of play up and down and side to side of the pivot inside the jewel or pivot hole. Side shake can be an indicator that a jewel or pivot hole is either broken or worn oblong. Excessive end shake can indicate that one of the jewels has moved in the main plate or bridge plate. Adjusting a jewel vertically to reduce end shake is included in our standard service. Replacing a broken jewel is not and you will be quoted for the additional cost. Each part is fully inspected under a microscope to make sure that everything is fully operational. Occasionally something like a cracked jewel will be revealed that was not detectable in the pre inspection. We will source the jewel and communicate the additional cost for replacement along with photo documentation for your approval before we proceed any farther.
Basically Epilame is used to change the surface tension on a watch part so that the oil doesn’t run off or spread. I use Epilame on the escape wheel, pallet fork jewels and the cap jewels. Preventing oil migration will extend the service life of the movement.
Install new Mainspring
It is good practice to replace the mainspring during a watch service. Most mainsprings I see are at least 40 years old. A worn or sprung mainspring will restrict the amount of available amplitude in a watch movement. Often times in a previous service the original mainspring was reused, and, in many cases, they are installed by hand without the use of a mainspring winder. This often distorts the mainspring affecting the amplitude. I never use old NOS vintage mainsprings in my watch servicing since I have seen many of them break because the metal has deteriorated over time. Good watch timing starts with high amplitude, so I always replace the mainspring in my standard watch servicing.
The pivots are at the bottoms of the wheel stems, the tips of the balance staff and in the stem of the pallet fork. These pivots get worn due to oil and dirt mixing together which increases friction, robbing amplitude and the accuracy in timing. Included in my standard service, I polish all the pivots to a mirror shine. This increases the potential amplitude and helps prevents timing faults later on.
Reassembling the movement
Lubricating with synthetic lubricant’s
The proper lubrication of moving watch parts is critical to proper timekeeping. Whether it is too much or too little oil, both will affect the watch negatively. Watch oils are specially formulated for different points depending on the speed the parts move at. Some oils like Moebius 9010, is a light synthetic oil used on high-speed area’s like the balance cap jewels, escape wheel, and seconds wheel. I use Moebius 9103 for high pressure, low speed areas like the barrel arbors, center wheel, and third wheel. The pallet jewels require their own lubricant called Moebius 9415. This is thick lubricant that holds its own under the high-speed contact between the pallet stones and the escape wheel teeth. For the setting system I use Molykote DX which is a very thick grease that stays in place and makes the winding of the watch work like butter.
Because of the importance of applying the right amount of oil to the pivot jewels and end stones all this work is done exclusively under the microscope. A typical pivot jewel is about 1 ½ mm wide with the pivot about 1/3 of that size in the center. To oil it properly a needle has to be dipped in the oil and applied right beside the pivot in just the right amount. Under a typical eye loupe this is virtually impossible to do accurately. The end stones that the balance pivots ride on also require pinpoint accuracy in oiling, so they are also done under the microscope.
Once I have reassembled and lubricated the movement, I give the watch a full wind and put in a dust free container to let it run for 24 hrs. After a watch has been serviced it takes about that long for the lubricants in the jewels to disperse and find their place. It also gives the mainspring time to stretch out and settle into the barrel. After 24 hours I put the movement onto the timegrapher which listens to the sounds of the pallet stones engaging with the escape wheel and measures 3 things. It measures the timing rate, how fast or slow the watch is running in the current position, it measures the Beat error, how close the timing of the tick and the tock are and it measures the amplitude which is basically the power the watch has. I check the watch in six different positions. With the dial facing up, with the dial facing down and 4 vertical positions, with the winding stem or crown facing up, to the left facing down and to the right. When these numbers are added together and divided by 6 it gives me the mean time average this watch is keeping. They will each vary slightly due to the changing forces of gravity and friction but when averaged together they should average a reasonably accurate overall rate.
Different pocket watch movement of different qualities all have different accuracy expectations. Typically, a 21-jewel movement is going to perform better than a 17-jewel movement, as a 17 jewel will perform better than a 11-jewel movement. Modern medium end movements can have a rate expectation of +/- 15 to +/-30 seconds a day depending on the caliber. High end movement on much more expensive watches can range from +/- 5 to +/- 8 seconds a day.
On vintage pocket watches some which are 140 years old that I work on, I have found that an accuracy rate of +/- 15 to +/-20 seconds a day is a reasonable rate depending on the caliber. Certainly because of the quality of my service methods I usually see much better rates than that especially on railroad grade watches, but to keep service rates reasonable you must have a standard and that it mine