Gruen Movement Catalog

Try the Movement Map!

Browse information about Gruen movements like never before using the new Gruen Movement Map.  Learn the approx age of your movement by looking up the movement's start of production date. Visually locate your movement on the map.

Gruen Movement Information Finder
Provides location of technical information in the Gruen parts books and the Gruen Repairer's Reference book

Caliber-Date Table... 2017 version

Use this handy table to get  a 'quick-read' on the age of your Gruen.  

Or, use it to dig further into the in-depth research on your watch.

Remember when using this tool....
  • It is one tool among many. Do not rely on it as your SOLE source of data. Doing so will automatically make you incorrect.
  • The researchers that created the table are human and thus error prone
  • Gruen made some movements for over a decade. This means YOUR movement could have been made on the date shown or up to 10 years later than that date.
  • The movements STOP at the 453 Material Catalog
  • The data originates from the list of movements found in the Gruen Material Catalogs. If it's not in a catalog, it is not on this list.
  • The movement should be marked with a quality stamp that matches the table.

That last one is important. You will not find the Caliber 510 movement, for example.  This is because all of the data currently being collected for the Gruen Movement Catalog are only movements that appear in the material catalogs.

A great amount of gratitude is owed to Barry Cooper for his work on the Gruen movement dates. He's been the 'keeper' of dates for over a decade now. My research assistant Cathy also played a crucial part in making this work happen.

Gruen Movement Catalog Summary

This is a start at the "big picture".  It's a bottom-up approach where movements are filled in based on the size of the movement. Hopefully this will all fill out to be a nice "Family Tree" look at Gruen's movements.

The quality is a little low on this chart as the images were sourced from a Swigart catalog. Working on getting images from the Gruen Material catalogs now to augment these.

Check back often for updates on this new section of the site.

Ligne Conversion Tool
Enter either Lignes or mm
Organized by Family - Curvex
Organized by Family - Veri-Thin
Organized by Family - Quadron
Organized By Size

8 3/4 "' x 9 3/4"'

CaliberJewelsPrecisionFamilySize WSize HYear of Intro 
43017YVeri-Thin8 3/49 3/41940
43115Veri-Thin8 3/49 3/41940
43517Veri-Thin8 3/49 3/41940
44017YCurvex8 3/49 3/41940

Missing from this table are "Adjustments". By 1940 all movements had moved over to using the new temperature compensating metal in the balance and hairspring known as Conoruma.  All movements by 1940 also used hairsprings with overvcoils. The combination of this advancement as well as other material and design improvements meant movements no longer needed to be "Adjusted".  

As will be seen in the future when Quadron movements are added, whether or not a movement was Adjusted did cause a caliber number change. Specifically, the 117 movements were Temperature Adjusted, where the 117N movements were NOT adjusted.  More research is needed to figure out the numbering scheme Gruen employed to see if adjusted / unadjusted movements were indicated in the Caliber Numbers or if this designation was linited to the 117N movements.
The Gruen Movement Catalog Description and Notes
The Gruen Movement Catalog  (a work in progress....)

Welcome to the movement catalog, another free resource for researching your Gruen watch! Like everything here this information is organized in a uniquely Gruen manner. We have data on Gruen movements that is specific & unique to Gruens and overlooked by other movement references. This information includes:
  • "Guild" member companies (i.e. ebauche makers)
  • Style Number data which informs the usage of these movements over time
  • Precision factory information (which factory type and location)

One can begin to piece together timelines and strategy when the movements are organized by size and by time.

This movement reference section is a new idea just starting to be built. It'll take time to build out but rather than build the entire database and then opening it up, I've decided to open access while it is being pulled together.  This is a multi-year effort, something not unfamiliar to anyone researching Gruens.  It's slow going, but with steady progress, really cool things can result.

Please do not download and post this information elsewhere, but do feel free to use it for your personal benefit as often as you like.

A HUGE thank you to folks that have given me permission to use their photos of this project!  I may or may not have used any of these images yet in the published database, but felt like thanking folks that have given me permission is the right thing to do as they've already done a nice thing for me in saying it's OK :-) 
Thank you ebay sellers:
  Richard Freilich and rtwatches
  Kimmysan from watchapalooza

Check out their stuff.  The photos they take are awesome and it's fun to window shop.
And eBay sellers are not the only generous people.... without the help of serious Gruen researchers like Barry Cooper, Bernd Riemann, and Steve Kirby the Gruen information you have available to your fingertips simply would not have existed. These gentlemen have been working behind the scene, providing us all with high-quality data and rarely given credit.  THANK YOU!  On every large Gruen project, I have much appreciation for the work done by my research assistant Cathy.  Thank you for the raw materials that enable good research.

If you're a reader of the site then you already know I take copyrights and ownership really seriously. If you see an image of yours in this catalog and you didn't give me permission to use it, then by all means contact me right away.  My first preference is to shoot my own photos, but I don't have photos of everything and for those rely on the generous help of others. I don't use someone else's photos without asking permission. If one of your photos somehow creeped in, I want to know about it as it shouldn't have been posted.
Own a copy of "The Gruen Watch Repairer's Reference"?  Then you're in luck!  You will find an index with almost 800 entries for the calibers of movements you will find in the book online, on the Gruen Repairer's  Reference Movement Caliber Index Page of course.

430/440 Family

Must start somewhere, so let's try 430/440 family as these are two of the most common Gruen movements.

The 430 Veri-Thin was launched in 1940 and along with it were the 440 Curvex and the 431, 435 Veri-thins. Together these cover the desired combinations of Precision, Veri-Thin/Curvex, and 15/17 jewels. The 431 is the 15-jewel, non-precision low end movement. The 430 is the 17-jewel Precision Veri-Thin high end movement. The 440 is the high end Curvex movement. In the middle is the 435, a 17-jewel non-precision movement.

Notice how the 430's train bridge has a faux escape-wheel bridge. It looks like the escape-wheel bridge is separate but in fact there is only one single large train-bridge. Presumably this was done to either make the movement look more valuable or to make it easier to identify the escape wheel. While I don't know for sure and haven't researched the history of watch movements that use this, I'm guessing it was for show not as a way for watchmakers to more easily identify the escape wheel jewels as even a watchmaker with only a little training can quickly identify which jewels belong with each wheel. If you know the answer, write me...

Style Numbers.... the secret weapon of Gruen watches...

Style Numbers have turned out to be an incredible resource for researching Gruen watches. It is a unique feature of Gruen watches and thus one that is not used or paid attention to by most collectors or researchers. If you don't know what they are then you should read the article on how to use Style Numbers to date your Gruen watch.

A few words of caution are in order when talking about Style Numbers.... They are not perfect in their ability to date watches nor are they highly reliable at identifying a single watch model as the numbers were re-used. But even with these weaknesses they are very powerful in their abilities to examine overall trends of Gruen watches.

You'll find a Style Number usage graph in each of the Movement Details pages. They graphically show the number of Style Number Pairs found for that caliber of movement. A "Style Number Pair" is a Caliber + Style Number.  It is the pair of numbers found in the interior of the back of the cases of most Gruen watches. An example is "440 450". This number you'll find in the back of Curvex Trooper model. It was also used with other models. The point is that one of these pairs may represent multiple models.

One of the outputs of the Style Number research was identifying all of the valid Style Number Pairs. You will find this list in one of the Tables in the Style Number Dating paper. To date there have been 1,238 valid Style Number Pairs. The Gruen Watch Catalog book has 4,368 photos of Gruen watches covering the period of 1923 to 1958. So the number of This number is about 1/4th the estimated number of Gruen watch models from the heart of Gruen's company history. The point is that Style Numbers were re-used and one can't look at these figures in absolute value terms, however, they are useful in making relative comparisons and I think most importantly, understanding how movements were used over time. 

Let's look at an example, the very popular caliber 440 movement. You will find this Style Number graph on the 440 movement details page.

This graph is a bar chart representation of this list of Style Number Pairs that are known pairs of Caliber-Style Numbers found in watches. This is the table of raw data graphed:

Caliber Style Style Date
440 448 1940
440 449 1941
440 450 1941
440 498 1942
440 499 1942
440 541 1945
440 544 1946
440 556 1947
440 568 1947
440 574 1947
440 575 1947
440 576 1947
440 577 1947
440 578 1947
440 584 1948
440 585 1948
440 641 1950
440 707 1950
440 753 1952
440 797 1952

We know that these Style Numbers were heavily re-used.  MANY watches were produced in 1940 that used the caliber 440 movement. The 440 498 pair is known to be used by The Curvex General and Curvex Sentry. Style Number 449 was used in the Curvex Commandant, Knight, Royalty. So we can't look at these number in absolute terms, but we can look at the trend over time and get some sense of how this movement was used. We can see, for example, that it first appeared in 1940 and was used in watches until AT LEAST 1952.

OK, now that caution has been advised when working with Style Numbers, I'm going to throw caution to the wind and stretch things a tad. I've counted the number of unique Style Number Pairs for each movement and graphed it in this bar graph below. What I am attempting to show is the relative popularity of movements. My assumption, which is probably not very sound, is that the Style Number re-use was done across the board, in a relatively uniform manner. Each caliber's count of the number of unique Style Numbers is low by a similar multiplier. Lost yet? It's OK, close your eyes and take a leap of faith and look at the graph as if it's completely valid.

Here is the graph of the top 30 Style Number Pairs. The numbers reflect reality in many ways. 

The top movements were:

  • 275 - Women's Veri-Thin 5.75 x 7.5
  • 215 - Women's 6.75 x 7.75
  • 3351 - Men's 8.75 x 9.75 21 jewel
  • 210 - Women's Veri-Thin 6.75 x 7.75
  • 290 - Women's Veri-Thin 5.76 x 6.75
  • 335 - Men's 8.75 x 9.75 17 jewel

The top movements in terms of Style Numbers used were small women's movements. If you look at the actual watch models being offered for sale every year in the Identification Guides you'll see that the majority of Gruen's catalog of watches for sale were small women's watches. Because Style Numbers were not used in the early watch models there will be a modern-bias in the numbers. More modern movements will tend to have more Style Numbers associated with them. It's just another bit of caution on top of a huge pile of cautions.

The Future

So where is all this headed?

Hopefully a fully populated database of Gruen movement.  That alone would be a great accomplishment. However, as the research has crawled forward, we're learning a LOT about other aspects of Gruen's history.  

The biggest question I still have and one that I hope will be answered eventually....
      What is the numbering scheme for Gruen movements?  How were the numbers assigned?

To answer that question, a large table will be populated and examined.

Here's an example of one analysis that led to figuring out what the "N" in the 117N movement means.  By populating this table:

Caliber Jewels Precision Family Rectangular Mvmt
Size Width
Rectangular Mvmt
Size Height
Round Mvmt
Size Diamater
Year of Intro Manufacturer Positional
Hairspring Typical Gender
430 17 Y Veri-Thin 8 3/4 9 3/4 1940 Gruen CONORUMA M
431 15 Veri-Thin 8 3/4 9 3/4 1940 Gruen CONORUMA M
435 17 Veri-Thin 8 3/4 9 3/4 1940 Gruen CONORUMA M
440 17 Y Curvex 8 3/4 9 3/4 1940 Gruen CONORUMA M
117 17 Y Quadron 8 3/4 12 1925 Gruen Y M
117N 17 Y Quadron 8 3/4 12 1925 Gruen CONORUMA sometimes M
157 15 Quadron 8 3/4 12 1925 Gruen Guild 4 or 0 M

Sorry about the formatting... it's difficult to be perfect 100% of the time :-)

What was discovered about the 117N movement was that it likely meant the movement was "Not Adjusted" or "Unadjusted". When all of the markings on the movements were recorded in the table, the major difference was the 117 movements were ALL marked as being Temperature Adjusted, and ALL of the 117N movements were marked Unadjusted.
Other theories about what the N means included "Narrow" because a couple of 117N movement were found in watches with narrower dials than normally found on 117 movements.  For a period of time "No difference" was seen between the 117 and 117N movements ;-)

From the data collected in the past few weeks, it's safe to say that 117N movements were ALL not adjusted while 117 movements had Temperature Adjustments. However, it's a stretch to say that the hairsprings differed between 117N & 117 movements across the board because not all of the balance cocks in the 117N movements were stamped with Conoruma hairsprings.
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