Watch Revival (Number 2)

Welcome to the second of our posts about mechanical watch revival.
 
Crispin Jones (Mr Jones) has been attending evening classes in watchmaking at Epping Forest Horological Club learning the skills of mechanical watch servicing and repair. In this second post, Crispin works on a Waltham Silver Trench Watch from 1914, firstly describing a little of its history:

This is another trench watch, but this time from an American maker - Waltham. American watches were extremely high quality (much higher quality than Swiss in their time). They took the best elements of the English watch (high quality engineering, top quality materials) but dropped the hand-made craftsman element. The American watch industry focused on very high quality, repeatable manufacturing, mainly using stamping presses to create the parts. They used semi-skilled labour and invested a great deal of time and attention on the machinery. American watches were more expensive than the hand-made watches from Europe, but they kept much better time too.

The American watch industry did something else very different from the European - they separated the manufacture of case and movement. Instead they made their movements interchangeable (at least within individual brand), so you could select the movement that you wanted and pair it with the case you wanted (or could afford). The retailer then assembled the watch for you. I guess if you had a sudden windfall that you could pop back to the jewellers and have your existing watch recased in a new, more expensive case. This is quite different from the English tradition where watch  movements were passed to casemakers, who in turn made a case that would fit just that specific movement (and no other!) 

The winding crown and tube is quite distinctive on American watches because it's a little more prominent than on a Swiss watch of this era. This is because the crown and tube are used to house part of the winding stem that is not removed when the movement is inserted into a case.

I brought this watch as a pair on ebay with another Swiss trench watch. The watch wasn't working when I got it and was in a pretty filthy condition, with the case badly tarnished as you can see in the pictures.

We can date this watch accurately because of the hallmark on the caseback. Hallmarks are one of the earliest forms of consumer protection (dating back to the 1400s). The hallmarks guarantee that the precious metal used in the item is of the stated quality, in this case that it is Silver.

 

The marks here show the following:
• At the top is the the lion passant (walking) used to denote sterling silver (that is silver of 92.5% purity also called 925, or Sterling silver).
• On the left is the anchor which is the mark for the Birmingham Assay office (the office that has certified the silver)
• On the right is the date letter "r" for 1916 / 17
• Underneath is the makers mark "A.L.D" which stands for Aaron Lufkin Dennison who was the founder of the Dennison Watch Case company. 

Also we can date the watch movement from the serial number: 20278575
There is a database maintained here that tells us: that the movement is a size 3/0 and was made sometime after 1907 (this movement is know simply as a "1907" which was the year it was first produced) and that it has 7 jewels.

It was clear from stripping the watch that the problem was the mainspring was broken. Fortunately it's still possible to buy new (old stock) Waltham mainsprings. Additionally a neat feature of American watches is the motor-barrel that is designed to prevent the sudden release of energy that occurs when a spring breaks from damaging the rest of the watch. 

  

I cleaned the case by gently rubbing the tarnish with a fibreglass scratch brush, wetted down with soap and water. I had to re-glue part of the dial that had chopped (near the 8 hour marker). The parts of the movement were cleaned in the rotary cleaner and then the watch was reassembled.

It's testament to the quality of manufacturing that the parts of this watch fit together beautifully - everything drops into place neatly (the only part that's a bit fiddly is the negative set keyless mechanism, this is what marries up to the winding stem that is part of the case) . Even though this watch is nearly 100 years old and it was some way below the top grade, there isn't significant wear to any of the pivots or metal bushings.

Once assembled and oiled (and rather to my surprise) it ran very strongly. I gave it to my girlfriend to wear for a few days to see that it was keeping time on the wrist and happily all seems good with it. My timing machine is being repaired at the moment, so I'm not able to test the exact +- seconds per day, but I'm confident it's running to within than a minute / day.

I love that the movement of the watch has blued screws - that is the steel screws are polished and then heated until the steel changes to an iridescent blue. This isn't entirely for decoration - the bluing process also hardens the screws to the right kind of hardness (somewhere below glass-hard, which would make them too brittle and too mild-steel which would be too soft). The blues screws show the attention to detail that went into the Waltham watches - this movement would have been (I believe) the cheapest that they produced with only seven jewels and no adjustments, yet they still felt it was important to ensure that the screws were correctly tempered. The strong running of the watch today is also testament to this uncompromising quest for the best.