I have this watch, a very nice Perret & Fils Swiss bar movement. What surprised me is the balance wheel: it is like an Earnshaw type, but monometallic and with isocronism screws. From the color is not brass and if the PW was, say, of 1920s I would have though it was an Invar. But ths watch has a "palm" trademark, as far as I know discontinued in 1897, and Invar is of 1896 ... theoretically possible, but I deem unlikely. Any suggestiom, please ?

oppps wrong picture, sorry. Now should be ok

Mario,
I'm more of a 'techie' than a historian, so I'll leave it to those that delve deeper into when materials were introduced to advise on the balance.

There does appear to be a joint in the rim, maybe composite material - or from being hand turned?
Experimental 'one off'?

For an instant, I thought it had vertical pallet stones!
The lever appears to be mounted on a threaded staff, something I've not seen before.

Any chance of a shot of the whole movement?

John

John,
you are 100 per cent right, the staff is threaded, or better there is a threaded SLEEVE around the staff ! I don't know why !
I am sending you also a picture of the movement whole, and I am grateful to you for your remarks.
Thanks !

and here is the movement

Hi Mario

A very nice watch and the questions show that you have a very close look to your watches.

First of all I would like to have another picture:
outside of the inner back cover. I think this is the place where you spotted the palm mark. I like to see the whole cover.

The threated lever stem is easy to explain. It was not unusual to screw lever and lever staff together at those times in swiss lever escapements(the early straight lever type). In most cases the thread is very short and almost not visible. At the complete lever you can only see on revolution of the thread and who tries to unscrew a lever?

The main problem with this watch is the dating. This type of watch was made over a long period.
The watch seems to be older than is actually is and so there is the possibility that the balance is nickel-steel alloy ('Invar')
Paul Perret was one of the 'frontliners' in the development of Ni-Fe alloys for horological use.
One patent dating 29th oct. 1897 in GB is titeled 'Improvements in Balances and Balance Springs for Watch, Clock and like Escapements':

"-The balance spring is made of an alloy the elasticity of which increases with a rise in temperature. Such an alloy is made of nickel and steel in the proportion of 27 or 28 of the former and 73 or 72 of the latter. A balance which only expands slightly is composed of 35 to 36 parts of nickel and 65 to 64 parts of steel"

I have seen a watch with similiar movement which has a 'anno 1843' on the inner cover and medals of exhibitions from years and years later. In 19th/20th century the writing 'anno 'year'' means made like it was done in 'year' or in the style of 'year'. So I think the watch is from about 1900 refering a 1843 bar-style watch of perret ?

Regards,
Gerald

Hi, Gerald. Thanks for your remarks.

Here there is the dust cover, the place where markings are. On the lower side you see the "LA PALME" trademark. On top, above the "Perret & Fils" there do is a "ANNO 1843", I think the year of foundation of the company, by David Perret Sr. As far as I know, La Palme has been registered in 1887 and discontinued 10 years after, so the PW should be dated after 1887 (and most probably on or before 1897). Anyhow, the Perret & Fils has been registered in 1883 and changed to Perret Fils in 1893, so the PW must be 1887-1893 ..

Mario

Thanks for the picture

Your explanation of 'anno 1843' makes sense.
I have the change perret & fils to perret fils 1896
Thinking that Perret patented 1897 the combination of balance and hairspring from Ni-Fe alloys, the dates are very close.

Gerald

Gerald, I run an esp@net search, and I discovered that Guillaume and Perret had similar patents, follwing the same reasoning, but Perret's ones are of 1897/98, Guillaume's 1905/12. Interesting, isn't it ?
In any case, I came to the conclusion that the watch was indeed a very advanced one, with the ideas of the 1897 patent in. Thanks, you have opened up a very useful investigation area to me !

Mario
That's part of the fun with horology!

Patent searches which are possible since a few years with aid of computers and online are a great source of information. It is a primary source and very helpful. sometimes I check only the names of great watchmakers. If i have a given number like often in suisse watches i check the name of the inventor for further patents.

Can you post the Guillaume pat. number ?

btw: Paul Perret had also the pat. CH0001 which is the first taken in switzerland when the potent office started in 1888. So he was very modern thinking and acting at his time.

Regards,
Gerald

Sure, Gerald, at last a firm footing to study relationships in that very secretive environment. Sometimes Swiss are unnerving. esp@net numbers are GB190521520 and GB19123847. As soon as I have a moment, I will search "Fabriques de Spiraux" ..
Thanks again
all the best
Mario