From The Bench: Springbar Specifications
DEC 07, 2021
You rarely think about them, but springbars are some of the most critical components of the watch. They’re like lug nuts on your car—not glamorous, but if they fall off, so do the wheels, and then you have issues.
There are some important distinctions between springbar types, and there are right and wrong ones to install on your watch.
The proper springbars ensure that your watch will stay on your wrist comfortably and reliably. The
wrong springbars could fall out, dropping your watch into the raging sea, seize in your watch and force you to saw them out, or even damage the lug holes in your case.
Springbars are designated by length, diameter and tip type. Length is pretty easy—you simply get the same size as your strap. Most Oak & Oscar watches take a 20 mm strap, so 20 mm springbars are the correct size. The Burnham takes 22 mm straps, so 22 mm springbars are proper on that watch. Note that the bars themselves will be slightly
longer than their listed length, as they are meant to be under tension while in the watch, so they should stick out slightly when installed loose in the strap.
Diameter is slightly more complex. The listed diameter of a springbar is typically 1.30 mm, 1.50 mm or 1.80 mm, which denotes the diameter of the thick middle portion of the bar.
Not typically listed is the diameter of the springbar
tip, which is also important, but luckily the tip thickness is fairly standardized. Fortunately, all Oak & Oscar watches take a 1.80 mm spring bar, so that part is easy.
Too-thin springbars allow too much play for the strap, which can actually cause the bar to get pulled out of the lug. Thin tips will also rub excessively on the inside of the lug holes, causing them to ovalise and expand, a problem that cascades progressively until the case needs to be replaced.
Springbars that are too
thick typically just don’t fit. Most dangerous is when the tip is just barely too thick and makes a tight friction fit to the case, because those can become hard to remove. Springbar tips should fit easily into the lug holes with a small, but perceptible amount of play. Again, standard 1.80 mm springbars are perfect in Oak & Oscar watches, but special springbars from other companies might cause an issue. If it feels excessively tight, don’t force it!
The last consideration is tip type, and this is
very important. Tips are typically described as “double flange” or “double shoulder.”
Double-flange springbars have two small flanges on the pins, allowing them to be manipulated by the fork of a springbar tool from the back of the watch. These springbars can be used on any watch, drilled lugs or solid. When in doubt, choose double-flange!
Double-shoulder springbars are deceptively-named, and simply have two smooth pins extending from the central portion. These are designed
only for watches with drilled lugs, and can be pushed in from the outside with the pin-end a springbar tool. Only Olmsted and Humboldt have drilled lugs in our catalog, so these are the only watches that should be used with double-shoulder bars.
There is a final category of springbar that you might encounter on an Oak & Oscar watch, and that’s the specialized bar in the clasp of our bracelet. Typical springbar tips are somewhat long, so as to provide a maximally-secure hold on the lugs. Clasp springbars, however, must fit into the thinner profile of the clasp itself, so they have proportionally-shorter tips to avoid sticking out the side of the clasp like a tiny pair of horns.
These springbars are only found in the clasp, so unless you accidentally shoot one off into the ether during an adjustment, you’re unlikely to encounter them.
The history and design of springbars may be interesting to the watch geek, so if you want to learn more, go read Hodinkee’s deep-dive from 2016 (this is one of Chase’s favorite articles)!
And for a TL;DR of this entire piece, here you go. Most Oak & Oscar watches take a 1.80 x 20 mm double-flange springbar, unless you have a Burnham, in which case it’s a 1.80 x 22 mm double-flange springbar. Now go forth and change some straps!
Historical Perspectives The Surprisingly Not Totally Boring Search For Who Invented The Spring Bar
The truth is out there, or maybe not.
JACK FORSTER
JANUARY 05, 2016
(The original impetus for this story was a question asked by commenter MrGrentch, in the comments section of our story on the Speidel Twist-O-Flex bracelet. Little did I know where it would go.)
It’s probably a good thing that nobody has ever asked me who invented the spring bar, because up until about a week ago, if they had, I’d have had to admit that I had absolutely no idea, and had never given it a moment’s thought. In fact, aside from occasionally cursing at one when it flew across the room during an ill-advised late-night impulsive strap change, I had hardly given spring bars any thought on any level at all for pretty much the entire time I’ve been interested in watches (which is longer than I feel like admitting).
They seem far too flimsy to have any of us trust a $200 Seiko diver to them, let alone, say, a $50,000 vintage Rolex (or whatever) and yet, they seem to be almost boringly reliable – mostly, anyway, and this despite the fact that they can’t be cleaned or serviced, and are basically disposable.
They’re ubiquitous to the point of invisibility, but the longer you think about spring bars, the weirder they seem. Of all the parts of a watch – any watch – they are undoubtedly the most pedestrian, and you can find, as far as I can tell, exactly the same spring bars holding a $75 watch on as you can find holding a $75,000 watch on. Some makers like to offer spring bars with little tabs that let you remove a strap with a fingernail; some will throw in gold spring bars with your gold watch (as well they should at those prices) but in every case, the basic mechanical principle is the same: a telescoping tube with two pins held inside watch lug holes by an internal spring; removing a spring bar requires the use of a little tool that if you're careless will let you put 10 years of wear on the lugs of your watch in about 10 seconds.
If you feel like ordering at least a hundred, Otto Frei will sell them to you (at the time of this writing) for the low, low price of exactly
94 cents a pop (“assembled by hand in a small village in Switzerland” no less, so bad cess to you, you non-small-Swiss-village-non-hand-assembling spring bar makers, may you and your shoddy wares be hurled into an outer darkness, where there is a wailing and a gnashing of teeth). They seem far too flimsy to have any of us trust a $200 Seiko diver to them, let alone, say, a $50,000 vintage Rolex (or whatever) and yet, they seem to be almost boringly reliable –
mostly, anyway, and this despite the fact that they can’t be cleaned or serviced, and are basically disposable.
In the course of trying to find out who invented the spring bar, I found out that not only did
I not know who invented the spring bar, quite a few other people didn’t know either – in fact, nobody seemed to know, including everyone in the office, all my usual backup sources, the heads of the watch departments at a couple of major auction houses, and several experts in horological history and the history of early wristwatches. This was provoking. Who, I thought, actually invented the goddamn things? I started doing some digging, and what I thought was going to be a straightforward 15 minutes or so turned into hours of going through increasingly obscure patent archives, which very slowly began yielding not just actual patents for methods of attaching a watch to a strap (easy to find) but things that actually looked like early spring-bar patents (a bit harder).
The Birth Of The Wristwatch
Naturally, you are not going to find patents for such methods until the general development of wristwatches began, towards the end of the 19th century. Wristwatches came pretty late to horology, though they have been theoretically possible for hundreds of years (the Earl of Leicester is supposed to have given a bracelet watch to Elizabeth I, for instance, though the question of what was the first wristwatch rapidly turns into the question of what you want to allow to be called a wristwatch; a rabbit-hole best left alone for now) but for much of horological history, wristwatch-sized movements would not have been very good timekeepers. And so, for centuries, watches on the wrist remained at best a minor footnote – with, certainly, little or no thought given to improving how you kept one on a strap, nor much incentive for coming up with one either.
Wristwatches before the 20th century were largely bracelet watches, and were worn almost exclusively by women, primarily as a kind of mechanically fascinating personal adornment rather than a precision timekeeper (sound familiar?). Really serious portable timekeepers, however, were invariably pocket watches, right up until the beginning of modern warfare. (One of the more common uses of the first accurate military watches was to help officers keep troops from wandering into their own side’s creeping artillery barrages.) Men in the field – at first officers, but then increasingly enlisted men as well – simply found it much more practical to look at a watch on the wrist than to consult one hidden inside a coat.
There were some interesting alternatives to the wrist as a place to put a watch on the body, in those early days. Below is an example of one such solution (with certain obvious practical drawbacks) from one
Martin Pierson of Connecticut, from 1898 (and while reading his patent, I got to wondering who had the job of
scanning all these obscure patents in the first place). The design partly answers the question of where modern brands get some of their ideas: from those who came before them. The Pierson patent may seem risible with the benefit of hindsight, but it has been resurrected – or at least, slightly re-designed, re-patented, and re-purposed – more than once, including
by the Swatch Group in 2008, so maybe the late unlamented Mr. Martin Pierson is going to get the last laugh. Back-of-the-hand watch, anyone?
From Wristlet To Wristwatch
The first widespread use of wristwatches for military service was probably by the British during the Second Boer War; these were generally leather cups meant to hold a pocket watch to a strap (often referred to as wristlets, or wristlet watches). Again, in hindsight, cumbersome and clumsy – but they worked. By the time World War I began, these had evolved into cases with wire lugs onto which a strap could be stitched; but prior to that, the first generation of wristwatches for civilian use were already being sold. Cartier, for instance, released the Tonneau, Santos-Dumont, and the Tortue all before the War began. Other than so-called “trench watches” with their wire lugs, watches prior to the invention of the spring bar were held on by a variety of means, though in general, the solution was to use fixed metal bars soldered in place, or rods held in place with screws (as for instance in the Cartier Tonneau) while metal bracelets would, of course, be soldered directly to the watch case. By the time
of this patent from 1924 there were already a number of different methods registered that offered various solutions to the problem of attaching a strap or bracelet to a wristwatch.
"Strap Attachment For Wristwatches" 1924 patent by August Beucke, Keystone Watch Case Co.
Wristwatch strap patent, 1917, Manhattan resident Victor Sence.
The obvious problem with many early methods is that they still didn't make changing a strap – or even getting one on in the first place – all
that much easier. And so, as wristwatches became increasingly popular after World War I, people started casting around for better solutions.
And this is where things get interesting if you're hunting for the birth of the modern spring bar. Now, a first pass through Google, if you look for “watch spring bar patent” yields several results, mostly from the period between the mid-1940s to the mid-1950s – although, human ingenuity and the desire to fiddle being what it is, you can find attempts to improve on or do away with the spring bar right up to the present day; in 1979, for instance, Mr. Bill D. Williams bethought himself of a novel way to attach and detach a strap using
push-button clips built into the strap (a bit Rube Goldberg-esque, but a novel method nonetheless). Another thing you find out in short order, is that the term “spring bar” considerably pre-dates the wristwatch, and over the centuries has meant different things to different people at different times (
here, for instance, the term is used in an article from 1833 that discusses a “spring-bar stirrup” – a device intended to reduce the number of fatalities due to falling from a horse with your foot stuck in the stirrup and getting dragged across the ground. In other words, from a horological research standpoint at least, a dead end).
Vintage Cartier Tank and Tonneau. (Image courtesy of Sotheby's.)
You notice two things looking at the first batch of search results: the first is that the terminology used to refer to spring bars is not uniform (“spring dowel” and “spring pin” both make their appearance, for instance, which means you have to try several alternative search terms to reduce your chances of not missing anything) and the second is that they are improvements on what appears to be an already common solution. In other words, by the 1940s, spring bars look to have been around a while. A patent applied for by
Robert Konikoff in 1946, for example, says, “As is well understood, these spring bars extend between the lugs on the wrist-watch case, and are provided with spring-pressed studs or trunnions at their ends for entry into the aperture or holes in the watch case lugs . . .” which clearly implies that spring bars were, by then, widely used. Another, applied for in 1946 and granted
in 1950, to Nunzio Guarneri, begins by noting that “the present invention relates to improvements in wrist watch spring bar (sic) and relates more particularly to the spring dowel bars commonly used to attach wrist watches to wrist bands or bracelets.” (The Guarneri patent application also cites as "prior art" a patent from 1899, granted to, of all things, the National Tube Company – a wonderfully generic name; was there a contemporaneous National Sphere Company? A National Cube Company? – which as far as I can tell after puzzling over it, has no relevance to spring bars at all. But no doubt Mr. Nunzio Guarneri,
requiescat in pace, had his reasons for citing the work of
Mr. David Heggie, whose identity is otherwise lost to eternity in the hall of mystery that is the saga of tube-making).
Konikoff's Spring Bar Patent, 1946.
Following The Trail Of The Spring Bar
Fortunately, the holders of these patents were meticulous about their intellectual antecedents. Following the bread-crumb trail of previously cited patents goes back further. In 1931, for instance, Elgin was
granted a patent for a method of attaching a watch strap with what look like spring bars, or spring pins, integrated with the strap.
But in the Guarneri patent, we find a trail going back further. One of the patents cited by Guarneri was published in 1929, and filed by an Isidor Dintsman (1886-1967) in 1927. Dintsman was the founder of the Diel Watch Case Company and his family had interests in a number of watch case and watch part businesses located in Queens, New York,
according to this post on a vintage watch discussion forum. The location for two of the companies was at 137-11th Avenue, and one of them – the I.D. Watch Case Company – was active up until the mid-1980s – at least, active enough to have a quarter of a million dollars’ worth of gold and diamonds
stolen from them in 1983. Here it is then, ladies and gents, in all its glory: what looked to me, at the time, like what must be one of the earliest patents, if not the earliest, ever granted for a spring bar:
1929, Isidor Dintsman Patent Wristwatch Spring Bar.
Here, interestingly, the language of the patent clearly seems to claim that this is a new idea. The introduction reads, in part, “This invention relates to a strap or ribbon holder and is especially applicable to wrist watches. By the present invention the straps or ribbons can be easily attached and detached by hand without the necessity of any special implements, while at the same time the straps or ribbons are securely held in place . . .” And
here is the patent in full.
I should mention, at this juncture, that here and there you’ll read that the earliest patent for a watch spring bar (at least in the USA) was granted to Fred Gruen for a patent filed in 1921. If you take a
look at the Gruen patent, you’ll see that it’s definitely a telescoping rod of some sort for holding the watch to a strap, but it doesn’t appear to be quite what we think of when we think of spring bars today (the inner rod is held in place with a sort of radial spring clip, rather than being held inside the lug holes by the tension of a helical spring).
Fred Gruen's 1921 design for Telescoping Strap Bars.
I felt pretty sure at this point that honor would be served if I just left it at that – after all, a spring-bar patent from 1927 seemed like it had pushed things back plausibly far. How wrong I was. While putting the finishing touches on what I thought was going to be the final cut of this story, I ran across this:
Charles Depollier And His Convertible Wrist Watch
Now this is
really pushing things back – all the way to 1915. This patent is for a system for a convertible watch – a way of converting a pocket watch to a strap watch, and vice versa. As you can see, it's a bit complicated and perhaps a little too difficult to use, and easy to damage. The system itself is pretty self-explanatory, and as you can see it
clearly relies on what for all intents and purposes is a modern spring bar. Charles Depollier, as it turns out, was a very interesting, if generally not-well-remembered figure in early American horology. He was a pioneer in watch manufacturing in America – a second generation owner of the firm Jaques Depollier & Sons, he produced watches using movements from well-known firms like Waltham, cased them, branded them under the name Depollier (his case company, a subsidiary of Depollier & Sons, was the Dubois Watch Case Company) and sold them directly to the public, with a showroom on Maiden Lane in New York City (the center, at the time, of Manhattan's Jewelry District). In general, most watches in those days consisted of a movement produced by one company, and a case by another, which would then be put together by a wholesaler.
One of his best known wristwatches was the Depollier "Waterproof Dustproof," which featured a locking crown, a screw-down case back, and features intended to reduce the effects of temperature shock; the watch was used successfully by aviation pioneer
Roland Rohlfs during his altitude-record-setting flight to 34,610 feet, in 1919. Depollier advertised Rohlfs' use of his watch extensively in trade journals at the time (an interesting example of celebrity watch marketing, some years before Mercedes Gleitze's swim across the English Channel made her a Rolex spokesperson).
Depollier was granted a number of horological patents – and his patent for a watch strap spring bar is the very earliest I've been able to find anywhere: filed in 1915, granted in 1916, and you can see the whole thing in
all its impenetrable legalese right here.
Spring bars, as we've already mentioned, aren't universally admired. They’re an oddly cheap-seeming solution to keeping a watch on a strap – especially a really nice watch on a really expensive strap.
That said, if I were to say, categorically, that Depollier was the inventor of the modern spring bar, I would almost certainly be wrong – after all, so often in the history of ideas and inventions several people are, at more or less the same time, barking up the same tree. There is at least circumstantial evidence that the spring bar in horology didn't originate with Depollier, and there is actual evidence that the spring bar as a fastener did not. For one thing, telescoping spring bars are quite a bit older than the wristwatch. Below is an illustration from a patent granted to Mr. T. R. Boone, in 1882, for a "cuff and dress supporter." The device is pretty clearly dependent on a telescoping spring bar, and the chances that nobody thought of applying this idea to holding a watch on a strap until Depollier's patent of 1915 seem awfully small (though someone had to be first).
For another thing, my lousy French and virtually nonexistent German means a lot of the European patents are harder for me to dig through than English ones. (Our columnist Louis "Bring A Loupe" Westphalen, who is a proud son of France as well as fluent in German, has taken up the challenge, but so far, he's come up empty for anything prior to 1915 in the European patent databases. Still, he hopes to eventually claim the prize of primacy in spring bar invention for France, or maybe the French-speaking part of Switzerland. Depollier's family was originally from Switzerland, in any event – a watchmaking family from the Joux Valley, as it turns out).
Spring bars, as we've already mentioned, aren't universally admired. They’re an oddly cheap-seeming solution to keeping a watch on a strap – especially a really nice watch on a really expensive strap. While they’re generally reliable, they do break from time to time, and if they do, there is nothing to do but hope your watch didn’t fall so far as to require servicing from the failure of a 94-cent spring bar (or fall off the side of a boat to spend eternity in Davy Jones' Locker). Acting as insurance against spring-bar failure is even supposed to be one of the advantages of a NATO strap. They are certainly less secure than quite a few other possible solutions (though these may present other issues; screws work loose over time unless you use Loctite, and so on). Not the least of the problems they present is that they give many of us delusions of being able to handle changing a strap or bracelet without leaving scratches on the lugs (proving once again that other than a bad watchmaker, the biggest hazard to any watch is certainly the owner). And yet, they are as seemingly indispensable to, and unavoidable in, modern watchmaking as the lever escapement, and for that, they deserve, if not genuine love, at least respect, for their vital but generally taken-for-granted role.
It is of course perfectly possible, and even probable, that the minute this story is published someone is going to read it, roll their eyes, sniff indignantly, and say, “The fool, clearly he is unaware of the
brevet granted in 1826 to [obscure name here] of Le Locle/Paris/La Chaux-de-Fonds/Geneva, for a ‘spring-actuated cylinder for the purpose of retaining a watch to a strip of leather on the arm,’ what
is the world coming to.” Having come this far though, I’d nonetheless be fascinated to know if anyone knows of a patent for a wristwatch spring bar that precedes the Depollier patent, and if you do, let us know in the comments. Why, it might even be that the bracelet watch of Elizabeth I was held in place with a pair of spring bars – unlikely, but one of the nice things about the history of watchmaking is that even when you think you ought to be able to be certain, you can never be quite sure.
If you'd like to find out more about the history of Maiden Lane and the New York Jeweler's District, check out this classic HODINKEE story about one of New York's most storied clocks, which is still ticking away at Maiden Lane and Broadway.
https://www.hodinkee.com/articles/sidewalk-clock
HISTORICAL-PERSPECTIVES
SPRING-BAR
www.halftimewatchmods.com
for posting this up, Mike.
