An investigation into movement finish - Up Close with the GO Panograph

[tempocalypse]

Over the past few weeks I have been examining the cal 61 movement in the Panograph with both a (somewhat weak) loupe that I have as well as under the Makro (its a Zeiss hence the K :P ) lens I have .

I have been attempting to gather a sense of how well the movement is finished driven partly by my own curiosity and subsequently some questions about GO’s finishing capabilities relative to its contemporaries I cam across on another forum.

Now I don’t claim to have enough frames of reference to be able to say anything declarative but I thought I would share some pictures along with my thoughts as well as some information I have gleaned from Glashutte themselves. (Note that all apparent dust is on the crystal)

To start with, the Panograph movement, despite the unusual dial layout, is at its heart a very traditional manual winding chronograph movement. The style of decoration is the distinctive and theatrical saxon style which is also used by A Lange & Söhne, Dornbluth, Nomos (Lambda etc) and Moritz Grossman.

Starting with the heart of the watch, immediately noticeable is the saxon signature hand engraved balance cock holding up the balance wheel. Engraved by free hand and then gold plated and subsequently rhodium plated (with the engraved recesses covered with resin) the engraving is a spectacular display of hand-craftsmanship

Furthermore, both the regulator itself and the swan-neck fine adjustment are both given the difficult treatment of Black Polish, also known as tin flat polishing. This again is both a time intensive and highly demanding form of finishing that results in a specular polish that in direct light appears to gleam with great brilliance or appear very dark or nearly black at off angles. It should be noted that most of these pictures are taken under diffuse light which lessens the effect, a few pictures further down will attempt to highlight the look of black polish.

You can also see the traditional style screwed balance wheel



From GO's website

""In order to achieve an especially flat and lustrous surface, parts such as the swan-neck spring, regulator, or screw heads, which are particularly easy to view through the sapphire glass case back, are enhanced using the traditional but at the same time very labour-intensive process of tin flat-polishing.

In this process, diamantine (a polishing paste) is applied to a flat tin file, which the operator uses to file the surface of the part until it is completely even and gleaming. The process can take several hours and is checked continuously with the aid of a loupe.

Polishing of a swan-neck spring (including the perimeters and angled edges) takes around 1 hour; to polish a sound spring such as that found in the “Pocket Watch No. 1” can take from 4 to 7 hours. Tin flat-polishing has a technical as well a visual purpose. The surface of the material is enhanced and offers greater protection against damage by moisture in the air and oxidation."





The heat blued screws are highly polished prior to the tempering process. They are also beveled and polished on the outer edge of the head and as the reflections in this picture make clear, also beveled and polished along the inner edge of the slot. This is often difficult to spot with the naked eye.

The screws are also sunken (except for those holding down chatons) and the edges of the holes are also polished




You will also note the extensive use of gold chatons to hold some jewels. Historically used to protect precious jewels from shattering during insertion, in the age of artificial jewels the primary purpose is tradition, aesthetics and as a sign of additional hand finishing. The holes are nicely polished although this type of chaton is not as spectacular as the raised chatons used by the likes of Moritz Grossman and Voutilainen




Looking at the anglage, the edges of all the bridges are beveled at a 45 degree angle and polished.

(at the limit of my camera and lens)



This seems very nicely done although when you compare with pictures of the very top level, it appears the very best watches use a curved edge rather than a straight 45 degree cut. Presumably this requires more work to polish well.

Comparing with my father's Breguet 7337, although the movement layout is more staid, the anglage on the Breguet seems to have a brighter more specular polish. Which is not to say the GO is poor, indeed the difference is seen only very up close but such are the fine margins that separate the good from the very best and I am under no illusions that GO is at the very top of the high end food chain. They've clearly made some compromises in getting to a more accessible price point.

Breguet 7337




Here we see two inward angles but the angle itself is curved rather than meeting at a sharp hand finished edge. Really sharp inward angles are difficult and rare even from the big names, from pictures I’ve seen most Lange and Breguet movements seem to avoid using these extensively as well (Even the Datograph gets only two, three on the perpetual version where they finished an identical corner more sharply in that version). Vacheron, who takes great pride in this technique, on the other hand put 3 even on their simple Traditionelle 3 hander caliber while top independents like Laurent Ferrier use them gratuitously.



The edge polishing on these steel parts are more brilliant than the bridges though as can be seen below.


I don’t have much to say about the “Glashutte Stripes” (Geneva stripes equivalent) except that they look very good to me. Only very few like Dufour seem to set themselves apart with their stripes finishing.



The chronograph lever edges are also beveled and highly polished



Here we also see that the beveled edges are polished while the sides have a grained finish. However the side of the tip, where it contacts the column wheel is if you look carefully is reflective and polished. This is a sign of good functional polishing (as opposed to the mostly decorative stuff we’ve seen so far) to harden and reduce friction on contact areas.

[tempocalypse]

Now I’ve been a bit critical of some aspects of finishing but here’s a very pleasant surprise: Having read on their website that the regulator and swan neck are black polished, it appeared to my eyes that quite a few other pieces appeared to have an identical finish (including some rather large ones). Given that black polish is supposed to be so hard I wasn’t so sure about about this so I wrote to GO asking about the parts I circled below. GO replied (also helpfully labelling the circled parts) confirming that indeed all of those parts, in addition to swan neck and regulator, are given a black polish!!!


"... After consultation with our watchmakers, I can assure you that all highlighted parts in the picture are enhanced using the traditional process of tin flat-polishing. These movement components are lavishly polished by hand with a tin rod until they are completely even and very shiny.


I have assigned your marked parts with the associated technical terms, thus you have an exact overview of the movement – as you can see attached... "



Nice perlage on the top plate can be seen in this image too ^


The black out effect of direct light at an offset angle






These investigations have been very educational for me. I’ve learned a bit more about what constitutes good finishing and although I found a few things to be critical about in the panograph (in strictly relative terms) overall I’ve come away with an even deeper appreciation of the amount of work the folks in the Glashutte Manufactory put into this work of art. On top of that the Panograph seems to have an extraordinarily large number of black polished components for a watch in its price range which was a pleasant discovery.


I hope you enjoyed the pictures (here’s a few more) and welcome any thoughts you all might have

[JohnF]

Here's something you might not be aware of: the blued screws also receive black polishing before the heat treatment.

Having done this, the process of black polishing is not all that difficult, just painstaking. Basically, you build a jig to hold the part in question at a set angle (the one you need to polish). You then take a sheet of good quality float glass, relatively thick, and then glue three sheets of mylar-backed diamond paper on that: one sheet of P1500, one sheet of P2500 and one sheet of P6000. The P1500 is grit 800 with an average size of 12.6 µm, the 2500 has an average size of 8.4µm and the P6000 4µm. Using just a small amount of watch oil and attaching the part in the jig (aka tripod), you start off the with P1500 to do the rough finishing, then to P2500 to remove any scratches and then finish with the P6000. The idea of using three is that if you have a problem due to a scratch at the P6000 level, you go back one step to the P2500 level, instead of having to remove a whole layer using the P1500 abrasive sheet.

The problem is that you do need to build a customized worktool to hold the item in a vice and be at exactly the right position. The screw bottom gets polished first, then you use a P1500 diamond bar to do bevel the screw slot and then a thin P6000 file to do the bottom of the slot and the beveled surfaces; then you do the top via the three steps as above. Hence you need a jig for the screw bottom, then a vice to hold the screw for the diamond bar and file (you can use a nice brass plate with screw holdings that you can also use for bluing for this purpose, works well place in a vice), then a final jig for the top plate. The tripod feet of the tripod jig for the top finishing of the screw get polished as well, so you have to adjust the fit whenever you put in a new screw to be worked on. Once you've got the tools, it's a fairly quick process: I think after a day I was putting black polish on screws at the rate of about 30 per hour. It does require significant concentration, good lighting and steady hands.

If you blue the screws without doing the black polish, you'll not get a very good finish (duh). Chemical bluing - the kind you see on a lot of Chinese watches, for instance - is easier, then the screws have only to be clean.

That said, black polishing and then bluing are attention to detail that raises the watch movement involved from the mundane to the sublime. :-)

[tempocalypse]

Here's something you might not be aware of: the blued screws also receive black polishing before the heat treatment.

Having done this, the process of black polishing is not all that difficult, just painstaking. Basically, you build a jig to hold the part in question at a set angle (the one you need to polish). You then take a sheet of good quality float glass, relatively thick, and then glue three sheets of mylar-backed diamond paper on that: one sheet of P1500, one sheet of P2500 and one sheet of P6000. The P1500 is grit 800 with an average size of 12.6 µm, the 2500 has an average size of 8.4µm and the P6000 4µm. Using just a small amount of watch oil and attaching the part in the jig (aka tripod), you start off the with P1500 to do the rough finishing, then to P2500 to remove any scratches and then finish with the P6000. The idea of using three is that if you have a problem due to a scratch at the P6000 level, you go back one step to the P2500 level, instead of having to remove a whole layer using the P1500 abrasive sheet.

The problem is that you do need to build a customized worktool to hold the item in a vice and be at exactly the right position. The screw bottom gets polished first, then you use a P1500 diamond bar to do bevel the screw slot and then a thin P6000 file to do the bottom of the slot and the beveled surfaces; then you do the top via the three steps as above. Hence you need a jig for the screw bottom, then a vice to hold the screw for the diamond bar and file (you can use a nice brass plate with screw holdings that you can also use for bluing for this purpose, works well place in a vice), then a final jig for the top plate. The tripod feet of the tripod jig for the top finishing of the screw get polished as well, so you have to adjust the fit whenever you put in a new screw to be worked on. Once you've got the tools, it's a fairly quick process: I think after a day I was putting black polish on screws at the rate of about 30 per hour. It does require significant concentration, good lighting and steady hands.

If you blue the screws without doing the black polish, you'll not get a very good finish (duh). Chemical bluing - the kind you see on a lot of Chinese watches, for instance - is easier, then the screws have only to be clean.

That said, black polishing and then bluing are attention to detail that raises the watch movement involved from the mundane to the sublime. :-)

Yes you are quite right that black polishing is for the most part time consuming more than difficult per se. That said it is not common to see many brands put in the time to do large parts like the jewel cap on the chronograph bridge and is quite special to behold. And thank you very much for that detailed explanation of the process!

Great pictures, and a great learning experience for me. Now I have to go get a loupe and compare my Traditionelle and my Senator Observer...

I'm sure you must have read the hour lounge article where Kari Vouitilainen himself gave his seal of approval with respect to the finish of that VC movement (in the American 1921 model but same caliber) I'd just take it on faith at that point :P (j/k Im sure it must be rewarding to look at it up close)

[tempocalypse]

Here's something you might not be aware of: the blued screws also receive black polishing before the heat treatment.

Having done this, the process of black polishing is not all that difficult, just painstaking. Basically, you build a jig to hold the part in question at a set angle (the one you need to polish). You then take a sheet of good quality float glass, relatively thick, and then glue three sheets of mylar-backed diamond paper on that: one sheet of P1500, one sheet of P2500 and one sheet of P6000. The P1500 is grit 800 with an average size of 12.6 µm, the 2500 has an average size of 8.4µm and the P6000 4µm. Using just a small amount of watch oil and attaching the part in the jig (aka tripod), you start off the with P1500 to do the rough finishing, then to P2500 to remove any scratches and then finish with the P6000. The idea of using three is that if you have a problem due to a scratch at the P6000 level, you go back one step to the P2500 level, instead of having to remove a whole layer using the P1500 abrasive sheet.

The problem is that you do need to build a customized worktool to hold the item in a vice and be at exactly the right position. The screw bottom gets polished first, then you use a P1500 diamond bar to do bevel the screw slot and then a thin P6000 file to do the bottom of the slot and the beveled surfaces; then you do the top via the three steps as above. Hence you need a jig for the screw bottom, then a vice to hold the screw for the diamond bar and file (you can use a nice brass plate with screw holdings that you can also use for bluing for this purpose, works well place in a vice), then a final jig for the top plate. The tripod feet of the tripod jig for the top finishing of the screw get polished as well, so you have to adjust the fit whenever you put in a new screw to be worked on. Once you've got the tools, it's a fairly quick process: I think after a day I was putting black polish on screws at the rate of about 30 per hour. It does require significant concentration, good lighting and steady hands.

If you blue the screws without doing the black polish, you'll not get a very good finish (duh). Chemical bluing - the kind you see on a lot of Chinese watches, for instance - is easier, then the screws have only to be clean.

That said, black polishing and then bluing are attention to detail that raises the watch movement involved from the mundane to the sublime. :-)

Actually just reading through your comment once more... I am not entirely certain we are talking about the same process. Apologies if I misunderstood, misread or if its an issue of terminology.

But my understanding was that true Black Polish/Poli Noir/Tin Flat Polish requires the additional step of polishing using diamond paste on a tin plate after the various grades of paper have been used:

http://www.watchesbysjx.com/2015/01/...polishing.html

Given different and conflicting use of terminology I have not been so successful in nailing down a precise definition from various online sources of black polish but the impression I have so far is that it does involve a tin plate to qualify.

Something to add from GO's website which I've added to the original post

"In order to achieve an especially flat and lustrous surface, parts such as the swan-neck spring, regulator, or screw heads, which are particularly easy to view through the sapphire glass case back, are enhanced using the traditional but at the same time very labour-intensive process of tin flat-polishing.

In this process, diamantine (a polishing paste) is applied to a flat tin file, which the operator uses to file the surface of the part until it is completely even and gleaming. The process can take several hours and is checked continuously with the aid of a loupe.

Polishing of a swan-neck spring (including the perimeters and angled edges) takes around 1 hour; to polish a sound spring such as that found in the “Pocket Watch No. 1” can take from 4 to 7 hours. Tin flat-polishing has a technical as well a visual purpose. The surface of the material is enhanced and offers greater protection against damage by moisture in the air and oxidation."

The work on the swan neck and other complex shapes I imagine presents a significant challenge compared with screw heads