HistoricTimekeepers Restoration Services and Supplies

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Notes for Young Watchmakers

HTI Approach to Service

Microscopes in Watchmaking

When only a watchmaker will do

The 37500 Contract Prototype

Restoration of Omega Jump Seconds Clock

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Approach To Service

When a timepiece arrives in my shop, I partially disassemble it and note all the defects I find.  I then provide a quote to the customer with the proviso that upon complete disassembly and cleaning some other things might pop up.  But, I know what tends to go bad in most situations, and I can generally tell when I really need to be careful based on the workmanship I find from the previous repairs.  I send the quote (along with photos if relevant) for approval by the customer.

Every timepiece is fully disassembled before initial cleaning.  This means every cap jewel is removed, the mainspring is removed from the barrel, every screw removed.  The parts are then precleaned in an older Varimatic ultrasonic machine to remove as much of the grit and old lubricant as possible.  This saves the cleaning and rinse solutions in the final cleaning machine, a four jar machine that meets the requirements established by most watch manufacturers.

The cleaning and rinse solutions are petroleum based so the cost goes up with the price of oil.  Aside from cost, disposal is an important responsibility.  Spent cleaners are given to my auto mechanic and the rinse is disposed of by using as fuel in my garden tractor.

After cleaning every part is inspected.  Pivots are refinished as needed, jewels inspected for damage, screws are refinished as appropriate.  The two jars on my bench are reagent grade heptane and reagent grade isopropyl alcohol.  These are used with swabs made from surgical sponge to remove any deposits that may have resisted the machine cleaning.  

To the left is a very badly cut pivot from being in use long after the lubrication evaporated.  To the right is the renewed pivot.

To learn more about the usefulness of microscopes, visit our Microscopes in Watchmaking page.

Below is a Hamilton 37500 aircraft clock's several hundred individual pieces cleaned and ready for inspection.

This is a marine chronometer being assembled.


About mainsprings.  They are expensive these days and many times need to have end hooks attached in order to adapt a new mainspring to a vintage watch.  But, the mainspring is extremely important for providing consistent power to the escapement and is the beginning of precision timing.  The other issue is that the old blue steel springs are now at least 50 years old and are fatigued and or rusted.  It is not unusual to have a blue steel spring break within a couple months of service, even if a "new" blue steel spring is installed.  Not only is this an inconvenience, it can result in actual damage to the watch.  Here is a side by side comparison of a new stainless steel spring next to a fatigued blue steel spring taken out of a WWII pocket watch.



I never use Rodico (a sticky paste sold to watchmakers) for removing stains or foreign matter on a part that is ready for assembly.  It leaves a residue and proper technique avoids the problem to begin with.

I use finger cots to avoid leaving oils from handling during assembly, I reclean any part that has been contaminated in the final cleaning machine.  I use suction to remove dust that may settle into the movement.

Parts like dials and hands are kept in storage boxes while the watch is being serviced.  Dials are wrapped in sterile tissue paper for protection.

To protect the finish on parts, I use bronze tweezers.  I rarely use steel tweezers for anything during assembly.

I use fresh lubricants.  When it comes to the escapement, I use a surface treatment (epilame) on the pallet jewels and escape wheel which the Swiss have proven keeps the oil where it is needed.

Parts DO fly away.  Any watchmaker who sez he does not pray on the floor weekly (really looking for parts) is not truthful.  To minimize the hassle, I use a roll top bench with the top left open only in the front.  I keep the bench top clear of anything but what I am working on at the moment.  These two practices minimize the time spent looking for a part amidst a jumble of movements and tools.  I have also sealed every floor to vertical joint within 15 feet of my bench so that parts cannot try to hide. When found, they get sentenced to the final cleaner.

If appropriate, the screws are all refinished by hand and blued using the traditional method of heat (no chemicals or lacquers).  The steel must be highly polished and chemically clean.  It is then heated until the correct color is reached.  This is actually an oxide that forms on the surface.  It is not only decorative, it provides protection against corrosion.  You can judge my consistency for yourself:

Upon assembly the timepiece is checked for performance on the timing machine, which reports information on the error rate, whether the beats are equal (beat error), and how much the balance assembly rotates (amplitude).  All of these are important parameters of watch performance.  However, it is not enough.

At this point, if it is appropriate to the piece, I adjust its rate to be within specifications for the number of positions specified for the model.  For example, a precision watch such as an American Railroad watch originally was specified to keep equal rates across 5 or 6 positions (Dial up/down and then the stem held in various vertical positions).  Using correct service procedures, it is possible to get most 100 year old Railroad watches to hold a rate that is within 15 seconds a day across positions.  This means that it will be a consistent timekeeper when in use.  The closer the positional rates in testing, the more reliable will be the rate in use.

I use 15 seconds a day for American RR watches because after 100 years of use, and the way many were abused by "watch fixers" in the last 40 years, it has seemed to be the most cost effective standard.  Originally, these watches were specified to keep a rate difference of 5 seconds per day across position (Omega/Rolex automatic watch performance!).  Indeed, I have had well treated examples that I could adjust to closer than that.

Part of adjusting high performance watches is checking and adjusting the escapement.  This often means making minute adjustments to the various parts.  This is the tool used to make precise adjustments to the pallet stones of the lever escapement to make the locks on the escape wheel teeth (what you hear as the tick) as light as possible and still safe.

If the watch is an automatic, it needs to checked to ensure the autowind works properly and the watch runs its full allotted time (determined by the manufacturer).

Also, just because the watch times out nicely on the machine (for 5 minutes or so), it is not proof the watch is functional.  I test all timepieces for at least 5 days against a network corrected time signal I receive from the Naval Observatory.

Only after getting past these tests is the timepiece ready.  I use a Mumford Timing Instrument to prepare the final report documenting the rate, beat error, amplitude and positional performance of the timepiece (again appropriate to the piece).

This report, plus any parts replaced, are returned with the piece.

All of these services are included in the prices stated for service.  You really do get what you pay for.

A note about casing.  You likely know my business is based on jobs others cannot tackle.  I service modern watches primarily as a service to those who become my customers.  I have chosen NOT to spend my capital on the latest casing and pressure testing equipment.  I do test water resistant cases to 4 ATM.  If a customer needs a case sealed to 12 ATM I refer them to others with the required equipment.  Bear in mind that 1 ATM is 14.7 PSI.  Most modern plumbing delivers water at 45 PSI. This means that even correctly sealed, it is strongly advised to remove your vintage watch while washing dishes or taking a shower; even if that watch is correctly sealed and meets the required standard of 3 ATM!

Finally, in the Swiss tradition I do what I can to stay in shape.  Watchmaking is a sedentary occupation which makes it too easy to fall into poor health.  Plus, being in shape does make a better watchmaker.  My wife and I are trail maintainers on the Appalachian Trail.

ATTENTION!  This year I several received requests to make corrections to several aircraft clocks under warranty.  I would have done, except the work was not mine.  Apparently there is someone very active on eBay using a similar sounding business name and a website that is similar in layout to mine.  While I am flattered, this causes problems for those who use and or collect aircraft clocks.  Every piece I service is recorded in my invoicing system and is tagged with my service label, as well as the mainspring barrel is marked in pen with the date and location of where the mainspring was last serviced.  Also, you the customer will have an invoice/receipt from Historic Timekeepers, Inc.

I cannot be responsible for someone else's work.



For shipping  or ordering information, contact:

Dewey Clark                   410.592.9998

Email Contact:         Historictimekeepers@gmail.com

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(Watch my hair go grey)