Lemania HS9 Chronograph calibre 15CHT

This lovely Lemania HS9 came in as a non runner recently for a spot of fettling and a service. These models are known as the HS9 after the engraving on the caseback. HS stands for Hydrographic Supplies (or Services), a government organisation tasked with the procurement of timepieces (and other devices) for the Navy. The 9 is the number of the specification that this watch was made to meet which was a wrist chronograph. Specifications 1 to 8 included normal wristwatches, deck chronometers, pocket watches and so forth. So this model is made for the UK government for issue to the Royal Navy Fleet Air Arm. This one is a silver dialled example but they did come issued with a white dial (with no luminous compound) for use on nuclear submarines and black dialed ones were issued to the RAF. These Lemania models were supplied to many armed forces the world over and are one of the nicest issued military watches in my opinion. It’s powered by the beautiful manual wind, 18,000bpm Lemania 15CHT movement. The dial has everything going for it, it’s Lemania signed with the company logo above, below that is the T – circle logo indicating the luminous compound is tritium based (rather than earlier radium), it has the broad arrow above the 6 denoting it was government property and it doesn’t have the long dash of luminous compound at the six o’clock marker which is sometimes seen. The crown isn’t the original but the style does suit the watch so it’s not too big a deal.

Lemania HS9 calbre 15 CHT

The back view shows that the H.S. /|\ 9 has been overscored with the Nato stock number 0552/924-3305 added above. This renumbering happened during the early sixties when watches were returned for servicing, so it probably had quite a long Navy “service” as it were. The watch belonged to an elderly relative of the current owner and he must have procured it during his naval career.

Lemania HS9 calbre 15 CHT

With the back removed the beautiful gilt calibre 15CHT movement is revealed. As can bee seen the balance has no shock protection so this one probably dates from the mid fifties or earlier.

Lemania HS9 calbre 15 CHT

With the movement removed and turned over I could now remove the dial and handset.

Lemania HS9 calbre 15 CHT

The crystal was very crazed with a split in the middle so I stripped the case and ultrasonically cleaned the case components….

Lemania HS9 calbre 15 CHT

….then fitted a new replacement. The bars on the case are removeable but I believe on this model they would have originally been fixed so they’ve been removed at some point.

Lemania HS9 calbre 15 CHT

Under the dial is relatively simple with just the keyless and motion work.

Lemania HS9 calbre 15 CHT

It didn’t take long to srtip this side at any rate 🙂

Lemania HS9 calbre 15 CHT

I’ve already removed the chronograph runner and minute recording wheel and bridge in this shot, along with the balance assembly.

Lemania HS9 calbre 15 CHT

The coupling lever and rocking pinion were next to be removed, this component engages and disengage the drive from the minute register wheel.

Lemania HS9 calbre 15 CHT

The coupling yoke and transmission wheel were removed next….

Lemania HS9 calbre 15 CHT

….then the column wheel, springs, reset hammers and start/stop/reset levers.

Lemania HS9 calbre 15 CHT

The train bridge was removed next, the click and upper crown wheel are fitted to the underside.

Lemania HS9 calbre 15 CHT

The view here is of the wheel train and the last bridge to be removed is the escape wheel one.

Lemania HS9 calbre 15 CHT

With the barrel opened and quickly cleaned to see what was going on you can see the resilient hooking has broken off the barrel wall end of the mainspring and the time honoured bodge of folding back the broken section and placing a section of spring in between it and the barrel walls hook had been used. This means the power reserve won’t be a good as it should be, not to mention the loose section of mainspring will sap power by binding on the lid and floor of the barrel itself. This was a bit of a worry because original spec mainsprings are unavailable these days!

Lemania HS9 calbre 15 CHT

This is all the components ready for cleaning and further inspection.

Lemania HS9 calbre 15 CHT

Lemania HS9 calbre 15 CHT

Fortunately I managed to track down an original spec 15CHT mainspring so the rebuild started with that.

Lemania HS9 calbre 15 CHT

Lemania HS9 calbre 15 CHT

The wheel train and escape bridge was next….

Lemania HS9 calbre 15 CHT

….followed by the bridge, pallets and pallet bridge.

Lemania HS9 calbre 15 CHT

The movement was turned over to refit the keyless and motion work.

Lemania HS9 calbre 15 CHT

This allows power to be wound into the mainspring so that the rough timings can be set up.

Lemania HS9 calbre 15 CHT

I rebuilt the balance assembly and fitted it but it had too much endshake and it ran very roughly in any position but dial up.

Lemania HS9 calbre 15 CHT

I removed the balance once again, and under closer inspection it could be seen that the end of balance staff top pivot had been broken off which accounted for the poor running. To rectify this the balance needed re-staffing so the hairspring and roller table were removed in preparation.

Lemania HS9 calbre 15 CHT

The staff was undercut with a graver and pressed out.

Lemania HS9 calbre 15 CHT

You can just about make out the difference in the length of the left hand end of the staff compared to the replacement.

Lemania HS9 calbre 15 CHT

The new staff was fitted and I check the poise of the balance which was horrendous!

Lemania HS9 calbre 15 CHT

This meant the balance needed to be re-poised, this is achieved by removing a timing slug from the heavy point on the wheel….

Lemania HS9 calbre 15 CHT

….then removing the very small copper timing collets from underneath the slug and replacing it. Place the balance on the poising vice and if it’s still heavy at that point then the collets can be refitted underneath the opposite slug.

Lemania HS9 calbre 15 CHT

This is repeated until the balance wheel is perfectly poised, or in balance. With this balance I had to remove some material from a couple of slugs as even with the collets replaced on the opposite slugs there was still a heavy point, this material is removed with a balance screw cutting tool.

Lemania HS9 calbre 15 CHT

I rebuilt the balance assembly and fitted it and the rough timings were then set.

Lemania HS9 calbre 15 CHT

The leverwork and wheels were now refitted, which was basically the strip down procedure in reverse.

Lemania HS9 calbre 15 CHT

Lemania HS9 calbre 15 CHT

Lemania HS9 calbre 15 CHT

Once it was at this stage and the depthing of the coupling wheels were checked I once again turned the movement over….

Lemania HS9 calbre 15 CHT

….and replaced the hour wheel and spring ready for the dial and handset.

Lemania HS9 calbre 15 CHT

The final issue with the watch was that the chronograph sweep hand was a bit loose on its pinion so I tightened the hands pipe up with a collet vice.

Lemania HS9 calbre 15 CHT

The dial and handset were now refitted….

Lemania HS9 calbre 15 CHT

…..the movement was recased and a new caseback gasket was fitted.

Lemania HS9 calbre 15 CHT

And the job was finally done, despite the lack of fixed bars and the incorrect crown I still think this one is a cracking example! 🙂

Lemania HS9 calbre 15 CHT

Lemania HS9 calbre 15 CHT

Lemania HS9 calbre 15 CHT

2 comments

    1. I try not to do any refinishing work on watch cases as I prefer a watch to survive as un-messed with as possible, the exception to this is when there is severe damage present. By polishing (especially mechanical polishing) you’re removing metal and the watch is no longer original. Many people will disagree with my view and prefer a shiny vintage watch, the thing is the more shiny ones there are the fewer untouched ones there are. They’re only original once!

      Like

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