Wednesday, 31 December 2014

The dreaded bodged impulse jewel "fix".

Waltham 1908 model Balance
A frequently fatal (to the watch) previous repair that I find quite frequently, both recently done to be able to sell a watch and others done many years ago.

Horologists please excuse some simplification and omissions here! Likewise I hope the non-specialist will not be too phased by a little bit of jargon.

What is the impulse jewel?

The impulse jewel is part of the balance wheel assembly, it is a small, often "D" shaped pin like jewel and is mounted on the "roller table".

The picture above right shows the balance assembly from an unrestored Waltham-1908 movement, the roller is the small disk in the centre of the picture with the balance staff (axel) going through its centre and the impulse jewel on the right - it is easier to see if you click on the image for a larger view.

Waltham 1883 movement. The lever
pallet is the dark bar like piece to the left,
the pallet forks are on its right side.
The escape wheel is below it (not quite in
position). This is laid out tangentially  as
an English lever but has a club tooth
escape so is a Swiss Escapement.
As the balance oscillates to-and-fro the impulse jewel contacts the pallet (lever) fork on each swing flipping it from side to side - the "tick" of a watch - this lets the escape wheel at the other end of the lever (on a Swiss escapement) or to its side (English escapement)move on one tooth for each swing and through gears this makes the second hand turn once a minute, the minute hand turn once an hour etc.

By some clever engineering  the impulse jewel also gives the balance a "kick" to keep it moving, it does this twice with every swing on a Swiss Lever escapement with a club tooth escape wheel, once on the unlock and once on the lock) and once every swing with a traditional English Lever escapement with a ratchet type escape wheel.

On an average size 16 or so pocket watch the roller is about 3.5mm / 0.14" in diameter so you can see that the impulse jewel it pretty small. And sometimes they break.

Wednesday, 24 December 2014

The Louis Brandt and Frère (Omega) "Labrador" movement.

Labrador 15J movement 1897/8
The restoration of a  watch by Louis Brandt and Frère with their "Labrador" movement dating from 1897/8 has prompted this post to correct a misapprehension by some - at least by some sellers on eBay - that the "Labrador" was a brand name used by the company to sell their Omega watches in North America. Whilst the movements were  sold there, that is not what the Labrador was about.

Like most companies Louis Brandt and Frère made a range of movements, in 1889 the 19 ligne (close to a Lancashire size 16) Labrador movement was introduced and in 1894 the 19 ligne Omega.
Omega 15J movement 1910

As can bee seen from the pictures (click on them for a larger view)  there is not a lot of difference in the basic construction and in fact most parts are interchangeable between the two types of movements if they are from around the same date. This includes the double action winding and setting mechanism which helped the watch be accepted for railroad use in some countries (not N. America).

Apart from a few cosmetic changes the differences are that the Labrador has screw set jewels and micro adjusted regulation whilst the Omega has machine set jewels and a standard index regulator. Both normally have a Breguet sprung cut compensating balance with double roller.

A 1901 Labrador type movement
stamped "Omega" just below the
"click" on the winding gear.

The cheaper Omega became very popular and in 1903 the company changed it's name to the Omega Watch Company but continued to make the Labrador either branded as such or sometimes as an Omega.

The Labrador was certainly still in production in 1905 but the latest I have seen is from 1904.

Web Site

Friday, 19 December 2014

J.W. Benson "The Ludgate"

Left: Size 13 Benson "Ludgate" 13J 1886, Right a size 22 "Ludgate",

The restoration of these Benson "Ludgates" have just been finished, the one on the left from 1886 and is a typical size 16, the one on the right is a size 22, yes 22, and is also in an oversize case. This post explains an interesting feature of the Ludgate design and illustrates a conundrum in dating the larger watch.

The movements are both engraved

J.W. Benson
patent No 4658
best London make
To H.M. The Queen, Ludgate Hill, London
which is a good stating point for both topics I want to cover. Firstly the Patent No 4658, this was for an integrated dust ring which also acted as a movement carrier.

If you look at the movement to the right you can see that the face plate is considerably bigger than the top plate forming an extended lip around the edge, also the barrel (bottom and just left of centre) extends outside of the top plate of the movement so clearly it cannot fit directly into a normal watch case.

Instead it fits into a substantial carrier and that slides into the watch case and is secured there by three cams. Normally the dust cover is hinged off of the carrier which means that it can only be removed from the case by removing the back cover first, a tedious, difficult and fortunately normally unnecessary operation. This size 22 movement does not work like that having the dust cover hinged, as on most watches, from the case itself.

I am not sure what was achieved by this patented design, a dust ring in light metal as used by Waltham and others would be much lighter and more convenient and give as much protection. It probably did not give any substantial protection either as, being key wound and set, there were two quite sizable holes in the back dust cover around the key guards which without a cover around the balance cock (as seen on some Swiss designs) would let in more dust than would ever get in from the sides.

Saturday, 6 December 2014

Beware the iPad!

A few weeks ago a customer returned a high quality watch because it was running very fast but when it reached me it was keeping time within a few seconds a day, after a prolonged test I sent it back. It then came back again with the same problem.

This time the watch was still running fast when it reach me and I was able to see that the two outer coils of the hairspring where "stuck" together, when freed the watch was again fine, keeping time to better than 5 seconds a day.

The cause of the problem was  the hairspring becoming magnetised, almost certainly putting the watch too close to the customers iPad, hopefully the watch will be OK when degaussed  - a tricky operation with a hairspring as it will vibrate with the degaussing field.

Don't get paranoid about it, but keep your watch away from computers, power-packs or anything else which might have a strong magnetic field.

Wednesday, 3 December 2014

An interesting watch case

This high end size 16 Waltham has an interesting watch case by the Philadelphia Watch Case Co.

The main body is either filled or rolled gold, the bezel and back are in American "Sterling" silver with the back inlayed with yellow, green and rose gold.

Click on the image for a larger view.