U.S. Army M2 Message Center Clock Chelsea 12E Movement

[SGM (ret.)]

So, after being totally motivated by the recent threads about Message Center Clocks, I took a deep dive into the clock collecting world to try to track one down for my militaria collection.  After some research, I decided to take a chance on one that was in less than perfect condition, but which was priced "right."

The clock I got had the glass broken out of it, the hands were bent into the dial-face, it wasn't running (reason unspecified by the seller), and it was missing the wooden transportation box.  Nothing wrong here!  LOL!  I figured if I couldn't restore it, then I could always get my money back out of it to put towards a better, more complete example.  The fun was in the research and challenge.  As it was, this resto has kept me busy for several months now, so it was, IMO, money well spent.

My first challenge was to see if I could research how to disassemble the clock to do what I could to bring it back to life.  I eventually found a couple of different .pdf versions of the US Navy Department, Bureau of Ships, NAVSHIPS 250-624-8 "Manual for Overhaul, Repair and Handling of U.S. Navy Mechanical Boat and Deck Clocks Chelsea Type."  Just Google this title and free to download copies will pop up.  If you have any mechanical skills and some few tools for doing fine work, with these instructions you can easily do almost anything to the Chelsea 12E (and 17E) Movement and Escapement to properly disassemble, clean and lubricate one of these clocks.  With some additional research, you can also learn how to do a number of other more complicated repairs.  I'm not going to lie to you and say that "it's so easy even a caveman can do it."  However, if you have the enabling skills, knowledge and ability to do fine, detailed mechanical work and the research needed to learn what to do, it is doable.

I' won't try to detail all of my work, but I will leave you with one bit of advice that took me a while to discover: DO NOT CLEAN THE ESCAPEMENT WITH ANY SORT OF CELLUOSE BASED SOLVENT - ALCOHOL, ACETONE, or LACQUER THINNER.  PERIOD!  Any of these solvents will dissolve the shellac that is used to glue the pallet stones and the impulse stone to their respective parts of the escapement.  You will ruin these parts, and if you don't lose the stones (which are not much bigger than grains of salt or sugar), you will have to find a real (a REAL!) clock maker to reset them for you.  Before attempting to even clean the movement and escapement, do your due diligence and research!

If you're not up to all this, do not despair.  Chelsea Clock made the 12E movement, used in the M2 (also used in US Navy Deck, US Lighthouse Service, and US Government clocks) to be sturdy and repairable.  Finding a clock maker who can work on one of these should be no problem.

After learning how to correctly disassemble the clock, I had to figure out why the clock wouldn't run.  I was hoping that it was something simple like a broken mainspring.  (Note, I have learned that "my clock doesn't work because the spring was 'over wound'" is a complete myth.  Either the spring will break, or it won't, but if it's fully wound, no matter how hard, it will just run unless there's something else wrong.)  In my case, the problem was the pivots on both ends of the balance wheel staff were broken off.  Because the Chelsea clock was produced in such numbers for decades, finding parts is not impossible.  I managed to source another escapement on eBay and used it to source a replacement balance wheel assembly.  (The staff can be replaced by a competent clock maker.)  The first picture shows my broken balance wheel in the platform escapement with the movement partially disassembled.

After fixing this, all the rest of the movement work was mostly simple disassembly, cleaning, proper lubrication, and reassembly.  Since the balance wheel assembly (which includes the hairspring) was replaced, I did have to do some work to regulate the time.  Again, learning how to do this (starting with the timing screws on the balance wheel) can be learned from online resources.

The next photo shows the condition of the hands and the clock face - dial after some preliminary straightening of the hands.  You can see where some of the paint had chipped from the hands in different places, and how the face of the clock was dirty.  However, there was no real damage to the finish of the face (no chipped or scratched black paint), so adding a new piece of glass, straightening the hands and touching up the chipped paint, and, finally, cleaning the face and refilling the etched markings with lacquer tinted to match the paint on the hands (not fresh pure white) was pretty straight forward.

The next two photos show the clock restored to running condition with the replaced bezel glass and hands and face freshened up.  At this stage, I was working on regulating the running speed.  Eventually, I was able to get the clock running well within the specified +/- 30 seconds per day (this clock now runs about -5 seconds per day or roughly -1/2 minute per week).

Once I had the clock running and keeping good time, I decided that it was worth the time and effort to make a reproduction wooden transportation box for it.

Continued research turned Whitney's book, "Military Timepieces" in which he included a chapter on the US Army's message center clocks.  That chapter (also printed as an article in the Horological Times magazine that can be found online for download) included a dimensioned external drawing of the M2 Message Center Clock transportation box.  With those dimensions, dimensions taken from the actual clock case, and a couple of dozen photos of original clocks in their boxes, I was able to "reverse engineer" the box and draft up a set of working plans for one.  The original specifications for the transportation box called for it to be made from hardwood with all of the parts for any given box made from the same species.  Based on photos of original boxes, the early ones would appear to be made from Mahogony while the later ones would appear to be made from white oak.  I guessing that US Navy demands on Mahogony for naval construction placed that wood in the "strategic" materials category (with the Navy having priority) so the US Army boxes were mostly made from oak.  The actual wood species and this variation is all based on nothing more than my personal observations and interpretations.  In the end, I elected to make my repro box from 1/2" thick white oak.

Hardware was another challenge.  The original hardware maker was Eagle Lock Co. in Connecticut which went out of business in the early 1970s.  In other words, original hardware is for all intents and purposes, impossible to find.  (In all of my searching, I was only ever able to find a single original wooden transportation box without a clock, and the clock collector who owns it would not even talk about selling it, much less entertain an offer to buy.)  In the end, I had to source a hinge, latches, screws, etc. from various sources.  The Chelsea Clock Co. is still in business, though, and I obtained an OEM leather strap handle from them, along with an OEM brass winding key.

The remaining photos show my reproduction transport box in various stages.  Finishing the box was done in accordance with the standards and specifications spelled out in a 1927 version of the US Department of Commerce for industries and vendors supplying the US government with products made from wood (again found online in a free .pdf).  It covers everything from paper to railroad ties and all in between.  The standards and specifications for finishing furniture and other fine wooden products called for stain, filler, shellac and spar varnish, so that's what I did with my repro box.

I'm pretty happy with the overall result.  It was a fun and educational project.  Clocks, timekeeping, celestial navigation and the history of the US Naval Observatory were all fascinating subjects, along with the mechanics of clock movements and escapements.  Even if you only have a passing interest in the clocks, themselves, I highly recommend Marvin E. Whitney's book, "Military Timepieces" from AWI Press.  In the modern world, we never really think about the complexity of timekeeping and the problems of long-distance precision navigation, but a century ago, all of this was really the high-tech GPS of its day and just as critical to national defense.



 

 

 

[VMI88]

Very impressive work!

[River Rat 1]

Nice job on that box. I have one with original box and if they were side by side, I could not tell what one was original.

[SGM (ret.)]

I appreciate the kind words, gentlemen!

[SGM (ret.)]

So, a local fellow militaria collector and friend asked me to take a look at his M2 clock and give him an assessment on the scope of work that it might take to get it running again.

 

It was one that he'd had for a number of years, purchased, I believe, from an "antique" (aka "junk") store for a very modest price.  It was in overall pretty sad shape - not working, the hour hand subassembly dynamically blown apart (the washer that goes between the hour and red time zone hands was "taco'ed" and both hands were off their ferrule), the minute and second hands were bent and chipped.  At some time in the past (before my buddy bought it water had infiltrated (through the winding hole, it would seem) and rusted up the mainspring, creating rust stains and some rust formation on a few other parts.

My buddy had used it as a "static" display type item mounted on a rough stand made from a couple pieces of wood rattle-can spray painted OD and screwed on with short deck screws.

At any rate, I blew it apart and found that the movement was nasty, covered in "gak" and rust stains.

I am happy to say, though, that after about 20 hours of work cleaning (and re-cleaning and then cleaning the clean parts again!), I managed to bring it back to life.  Replacing the mainspring was easier than I anticipated.  The main challenge was to free up the minute hand clutch spring mechanism.  This took quite a bit of work, but it's good now.  The cosmetic work on then hands was straightforward.  I left the face/dial alone.  I was tempted to refinish the scratches, but they were only a small few and once the face was cleaned, they looked about right for the age and use.

I did "reprofile" my buddy's homemade stand and replaced  the mounting screws with the correct, blackened slotted, brass #6 x 5/8 wood screws.

The clock's now running great and keeping very good time.  Although not in a correct wooden transport box, the display stand looks pretty good and seems appropriate for an Army Message Center Clock.  You could easily imagine it on some commander's desk in his garrison office.

[SGM (ret.)]

I forgot to add the picture of the repaired hands and cleaned dial/face.

One thing that really convinced me to leave the dial alone was that the luminous dots, triangle and square next to the numbers still glowed in the dark.  The luminous material on the hands was covered with black mold and mildew spots, but I was able to match the original color and repaint those areas with modern luminous paint (no radium, LOL!).  I was glad to see this, though, since I now have a very accurate color match for the original luminous paint.  (Which I'll use to touch up the hands and dots on my own clock at some time in the future.)

Anyways, these clocks have a very "brutish" and industrial look to them, but this one is still quite attractive.

[Redleg130]

I found a Clock, message center, M1 which appears to be 1940s manufacture according to the serial number lookup I found.  Chelsea also will lookup manufacturing details for a small fee.

 

Chelsea Clock Museum - Chelsea Serial Numbers

Chelsea Clock Serial Numbers & Certificates of Origin

 

This clock I found works, but before I messed with it I took it to a professional (he had the magnifying monocle and the whole bit) who was very helpful and shared details about it with me.  He looked it over and determined it didn't need any services to operate normally so it must have been stored well fortunately.

 

Ill build a box for it and it will make a great addition to my communications shelter setup.  It keeps time perfectly so far, and the spring that powers it lasts quite awhile, just a small handful of turns has powered it for over a week and its still going.

 

Ill post photos of it when complete and in the setup.  I am very happy to have found this thing, I wasn't aware of these at all until recently.

[Redleg130]

I have searched extensively, but am unable to find the article mentioned above, or any other reference for the box dimensions.  Does anyone have these dimensions?  I can probably approximate this from the photos, I have even thought of modeling this with foam and cardboard to ensure the dimensions actually work without collision, but having the proper sizes and angles would ensure I get close to as issued as possible.

[Redleg130]

As a test, I wound this clock up and observed it daily.  A single wind up lasted 16 days and it did not lose any time in those 16 days.  I used my cell phone clock as the comparison, only observing minutes.  Quite impressive I think.  I am not sure what a clock professional would consider good, and I cannot find (using the terms I am using) a method of measuring accuracy, but this seems more than serviceable for a device made 80 years ago. 

 

Included this bit of info since I wasn't sure what a normal run time would be, and now that I know, I wanted to share.

[Redleg130]

Three attempts to make the box and a pile of ruined lumber, but I think we got it.  My son, who did almost all the work on this, will write up some specifics if someone wants to build a box at least similar to the photos I have found.  We skipped the backing board element which would have been nice, but this was a major challenge to build as it was.

 

Dimensions are 10x6x9 with the front lip at 1 1/2 in, and the rear hinge at 5in at a 30 deg angle.  Cherry would look nice, but isn't as tough as oak, third iteration was oak.

 

The first box would not open with the clock in it, and had other flaws.  The second box we tried cutting angles after assembly and this didnt work at all.

 

The two critical elements are the box hinge open without colliding with the clock face, and that the two halves end up falling even when fully open so the clock has a stable base to rest on when in use.

 

I am sure a professional woodworker will find flaws.  I am more interested in sharing data with someone that can use it to get pointed in the right direction which is why I am posting this.  It will serve its purpose of protecting the clock in transit, which is the primary goal of it, and I think it looks fairly nice even if not perfectly matched to GI.

 

[Allen0820]

WELL DONE!  I've had many of the message center clocks over the years, ditto U.S.N. Deck clocks; many not running but I never had the skill or motivation to restore / re mfg.  A salute to you.  If I can get the energy to dig it out, I'll soon post a U.S.N. cased chronometer.  

[Redleg130]

Yes please do

[Redleg130]

Summary - Final dimensions as 10" H, 9" W, 6" D.  The two critical elements are that the two halves fall equally when opened to provide a stable base for the clock to sit when in use, and that the box hinge open without collision with the top of the clock face.

 

There are no officially documented blueprints for the construction of an M 1 or 2 Message Center Clock box (that I could find), although several pictures are available online.  One such picture was available from the IMA website, which gave outside dimensions of the box as 9" W x 4.5" D x 10" H (although these dimensions ended up not working on our example with the materials we had).

 

The box appears to be made of oak, based on the grain pattern and has no visible fastening on the outer surfaces to indicate nails or screws.  This would suggest the construction is primarily held together with wood glue, with possible pegs or wedges acting as secondary support.  Given that I do not have a box to deconstruct for reverse engineering, I cannot verify the exact construction.  Tongue and groove reinforcement does not seem to be likely, however, given the lack of evidence on the internal edges.

 

When I constructed this box, I purchased readily available 3/4 inch oak boards from the local hardware store.  These are listed online at Menards or Home Depot.  It is not unlikely the genuine box was made from different thickness lumber, as modern dimensional lumber varies from historical dimensions due to construction conveniences (hence why a 2x4 is measured at 1.5 x 3.5).  In any case, this thickness appears fairly appropriate to the pictures available.  I purchased 10" wide boards, which were 9.5" dimensionally.  This allowed for the correct width of the box without need for edge gluing.  I Measured the clock and I had to be just under 6" (around 5 7/8 inch or so), so this left roughly 1.5 inches in the internal area if two 3/4 width boards are factored in.  When placed on its backboard, the depth of the clock was just under 4 inches.  This would not have worked with the dimensions available on IMA, since two board thickness would have left only 3 inches on the internal area.  So I opted to go with a 6 inches of depth for the box.  This
left final dimensions as 10" H, 9" W, 6" D.

 

The box front and back boards were 7 1/2 inches wide, to allow for the side pieces to run to the front, as it looks in the photos.  These were overcut to around 10.5 inches, to allow cutting width of the blade when making the opening.  This was also true for the side pieces, which were 6 inches wide.  The angle of the box cut was approximately 30 degrees.  I first attempted a 45 degree angle but the height of the box appeared odd.  30 degrees allowed a good fit between the top and bottom portions of the box.  To do this correctly, I made the cut from the back ends of the side pieces, marking the start of the cut at 5 inches, and setting the saw miter to 30 degrees.  Doing these cuts at the same time prevents angle ambiguity in resetting the miter, which prevents headaches in future assembly.  Cut both side pieces, then partially assemble the bottom portion with both front and back.  Mark the area where the bottom of the angle meets the front piece and cut the front with a 30 degree angle on the blade.  You can trim the excess wood from the top before final assembly.  For the back piece, since there is a hinging mechanism, the angle would impede on opening, so make a straight cut at 5 inches.  This should be verified with the dry assembly as well.  The bottom and top caps can then be cut based on how the pieces fit together, or roughly 7 1/2 inches W x 4 1/2 inches.  Test fit these pieces together, trim as needed, and glue or screw into place the pieces.  I found pre-drilling and countersinking the holes are needed, as oak is prone to splitting.  For a static display box glue might work, but if this used as a transit case, screws or dowls would be needed for durability.  This example will be used as a transit case thus screws were used.  This introduces the holes seen in the photo, which isn't in the originals, so dowls may be an option if you want an unblemished example.

 

The next factor to determine was construction of the backboard itself.  The wood edge around the clock looked to be around 1/4 inch, so I cut a roughly 6 1/2 W  x 7 1/2 H slab.  This allowed me to find the center of the semicircle by placing a compass where it met around the top and both sides of the boards.  I scored a line to mark the edge of the semicircle and cut the circle out with multiple cuts on the table saw, finished with a belt sander to meet the line.  This could also be done on a bandsaw or scroll saw, but I wanted to get cleaner edges.  I placed the clock on the centerline of the board and roughly placed it where all edges looked equal.  This allowed me to mark the top hole for the screw and pre-drill.  This let the clock hang so I could mark the bottom two holes when it was partially installed.  The backboard can then be fixed into place within the box by drilling two holes into the bottom of the box and running screws into it.  Additional support can be provided by a screw in the front of the backboard, running through the back of the box.  Just make sure it is a short enough screw that it does not penetrate through the back.

 

Stain and a layer or two of protective coating (I prefer Tung Oil), then you can install the hardware.  Hardware itself is available at any hardware store, but mine came from Rockler.