Watch Regulation Guide

Watching a movement kick into life during a service or restoration is an immensely satisfying experience, but, beyond being simple mechanical pieces of art, watches are tools that are intended to tell time accurately and reliably, so the running movement will need to be regulated. Regulation is the process of adjusting the timing of a watch to ensure it keeps time within acceptable limits. This guide will walk through the basics of watch regulation and delve into some best practices that help ensure good results.

Regulator Designs

Before diving into the regulation process, it's helpful to understand the different types of regulator designs commonly found in mechanical watches. Most watches, particularly vintage models, use some form of Index Regulator, which features a movable index with a pair of curb pins, mounted on a movable index carrier, that surround the hairspring and constrain its horizontal movement, thereby changing its effective length. This, in turn, changes the oscillating rate of the balance. Older watches tend to have a pair of simple, fixed curb pins, while more modern watches generally have a single fixed curb pin paired with an adjustable curb pin that can be rotated to change the geometry of the regulator gap. Adjustable curb pins also typically have a retaining shelf that keeps the hairspring in the regulator when the adjustable pin is closed. This is in contrast to fixed curb pin regulators, which are usually open at the bottom, so the hairspring can drop out of the regulator when the balance is removed (which isn't usually a problem, but something to be aware of).

There are also a variety of adjustment mechanisms for index regulator arms. Some simple designs forego an adjuster altogether, requiring adjustments to be made by directly moving the index carrier that supports the curb pins. Many have a regulator arm that extends over the balance cock opposite the index carrier and allows the regulator to be adjusted more easily and safely. More sophisticated (and generally higher end) designs also incorporate some form of fine screw-driven adjuster for the regulator arm. Ideally, these are engineered to allow the index carrier to be moved separately for coarse adjustments, while the screw mechanism can be used for fine adjustments.

Regardless of the exact design, index regulators all follow the same general principle: moving the index carrier and curb pins closer to the hairspring stud makes the effective length of the hairspring longer, slowing the rate, while moving it away from the stud does the opposite, making the watch run faster.

There are also watches that use so-called free-sprung balances, which do not have a traditional regulator with curb pins. Instead, these balances use adjustable weights on the balance wheel itself to change its angular inertia and regulate the timing. These are relatively uncommon in vintage watches, however.

Using a Timegrapher

In this day and age, a Timegrapher can be considered an essential tool for watch regulation. Of course, it's still possible to regulate a watch using traditional methods, which generally involve comparing it at regular intervals to a reference clock over a period of hours or days, but this is incredibly tedious compared to using a timegrapher, which provides instant and accurate measurement of the watch's rate, as well as other important parameters like amplitude and beat error.

I won’t go into the ins and outs of actually using and intepreting the results of a timegrapher here - I am assuming you are familar with your timegrapher and know how to read it. There are a ton of introductory videos vying for your attention on YouTube if you are new to timegraphers (as per usual, Mark Lovick’s videos are highly recommended). Here are a few timegrapher usage tips specific to regulation:

  • Regulating on the Timegrapher: It can be convenient to regulate the watch, particularly when you’re trying to establish a dial-down baseline, with the movement mounted in the timegrapher, because you get instant feedback on your changes. There are some downsides to this however. Notably, this doesn’t give you the most stable platform for making fine adjustments, particularly if the regulator is “tight” and requires significant force to move. Also, this raises your movement pretty far up off of your work surface, which can make it difficult to use microscopes to view fine adjustments. Overall, I think it’s fine to keep your watch on the timegrapher when you’re trying to get in the ballpark, but it’s better to move it off the timegrapher onto your work surface to make really fine adjustments later in the process.

  • Workspace: Because you may (eventually) want to shift to making adjustments to the regulator on your work surface, then checking the result by placing the watch back in the timegrapher, it’s helpful to clear enough space so that you can position the timegrapher microphone stand next to your work area and easily move back and forth between adjusting and testing/checking. Obviously, you also want to make the the timegrapher microphone stand is stable, won’t collide with anything, and is as isolated as possible from noise & vibrations (other than those coming from the watch).

For now, it's sufficient to understand that it may be difficult or impossible to regulate a watch properly if it has poor or inconsistent amplitude or a large beat error. Therefore, it's important to address these issues prior to final regulation. For the time being, we will assume that the movement is running well and we can focus on adjusting the rate.

Basic Regulation Process

The regulation process itself is fairly straightforward, but it does require a steady hand, good vision, and a bit of patience. Here are the general steps to follow:

  1. After servicing and lubrication, let the watch run overnight to allow the lubricants to settle and the movement to stabilize. It's a good idea to let it run for an extended period in both dial up and dial down positions before final regulation

  2. Ensure you can mount the watch securely on the timegrapher. If the movement is not cased, use a movement holder to keep it stable.

  3. Make sure the watch is fully wound to ensure consistent power delivery during regulation.

  4. If you disassembled the balance cock during servicing (e.g to clean and oil the top jewels in a non-shock protected movement), it may be helpful to return the regulator to a neutral position first.

  5. Turn on the timegrapher and start a measurement. Give the watch 5-10 seconds to stabilize before taking readings.

  6. Make small adjustments to the regulator position (the method for doing this varies depending on the design of the regulator - see above), repeating measurements after each adjustment to monitor the effect on the rate.

  7. When you have achieved a stable rate, repeat the process for the other positions (dial up, dial down, crown up, crown down, etc.). The objective is to find a compromise adjustment point so that the watch runs at an acceptable rate averaged across the different positions, potentially with more weight given to the most common positions (see the discussion of watch positions below).

  8. Once you are satisfied with the regulation, it's a good idea to let the watch run for a few hours to a few days (if possible) and then recheck the rate to ensure it remains stable.

Tips and Best Practices

Here, in no particular order, are some tips and best practices to keep in mind during the regulation process:

  • Make small adjustments: With some movements, even a tiny movement of the regulator can have a significant impact on the rate, and it's very easy to overshoot the desired adjustment as you get closer to the target, so be patient. There are a few tricks that can make it a bit easier to make small adjustments more reliably:

    • Magnification. Using a loupe, or working under a microscope, can help you see tiny changes in the regulator arm position more clearly.

    • Brace your hand or tool against a stable surface, and make sure the watch itself is securely held in place. Adjusting the regulator with the watch on the timegrapher can be convenient, but it can also make it difficult to make fine adjustments.

  • Use an appropriate tool:

    • For direct adjustment of the index carrier, it's helpful to use a dedicated tool that engages securely with the edge of the carrier and keeps the hairspring out of the line of fire. Personally, I have fabricated a simple tool for this purpose by filing down a cheap spring bar tool, leaving a small notch at the tip to engage with the index carrier. This has worked quite well for me.

    • If the regulator has a basic regulator arm, I favor using a plastic pointer stick to adjust it. This protects the balance cock from scratching. I find that you can sometimes place the tip of one of these tools alongside the regulator arm and twist it, rather than pushing, to make very fine adjustments.

    • If the regulator has an adjusting screw, your job becomes a lot easier, but make sure to use the proper size screwdriver.

  • Keep an eye on the amplitude while you're taking rate measurements. Often, moving the watch around will cause the amplitude to shift or drop somewhat. Wait for the amplitude to stabilize before taking a reading.

  • Working through all of the positions in sequence can definitely be a bit tedious. While it's a good idea to do this for the best possible results, I have found that, as quick and generally quite good approximation, you can try deliberately setting the rate 3-5 seconds fast when the watch is in the dial-up position, and then check the crown-down position to see if the rate is within an acceptable range. This works because most watches will slow a bit when moved from dial-up to crown-down, which are the two most commonly encountered positions when most people wear their watches.

  • Be patient. Regulation can be a bit of an art form, and vintage watches in particular are not always easy to regulate. It may take some time to get the hang of it.

Watch Positions

When regulating a watch, it's important to account for the different positions or orientations that the watch will encounter while being used, but not all of these positions contribute equally to the real-world timekeeping performance of the watch. It's important to think a bit about how the watch will be used in practice. This can even vary significantly from person to person, so if you know the owner or prospective owner's habits, you can actually optimize the regulation for their specific needs. Here are a few things to consider when deciding how much weight to give to each position during regulation:

  • The (perhaps unfortunate) reality of modern life is that most watch wearers will spend a large chunk of their day in a seated position. Coupled with the fact that most people wear their watches on their left wrist, this means that most watches are likely to be found somewhere between the dial up and crown-left positions for much of the day, so I tend to weight these positions more heavily during regulation.

  • If the watch is a daily wear item, it's also likely to spend the overnight hours on a nightstand. This has somewhat different implications depending on the watch band: Watches with leather straps will likely end up in the dial-up position during overnight hours, while those with metal bracelets tend to rest on their side in the crown up position more often than not. Either way, it's a not a bad idea to factor that into your regulation process.

  • If the watch owner is particularly active or engages in activities that involve a lot of wrist movement, the watch may experience more variation in position throughout the day. In such cases, it may be beneficial to give more weight to multiple positions during regulation. For example folk who stand or walk a lot will put their watches in the crown-down position more often. Of course, this is highly individual and I tend not to assume it's true unless I know better ;).

The reality is that there's no one-size-fits-all approach to weighting watch positions during regulation, but by considering the owner's habits and lifestyle, you can make more informed decisions that lead to better real-world timekeeping performance.

Troubleshooting

Vintage watches can be cantankerous creatures, and sometimes regulating them can be surprisingly challenging. Many if not most common regulation issues arise from underlying amplitude challenges, and those will be covered in a separate guide. So, assuming that you've already addressed any amplitude issues and the watch is running with good amplitude in all positions, here are a few other common regulation challenges and suggested approaches to addressing them:

Excessive Beat Error

If the watch exhibits a significant beat error , it can complicate the regulation process. Beat error occurs when oscillation of the balance wheel isn't centered on the engagement point with the pallet fork, which causes an uneven beat (i.e. the "tick" and "tock" have different durations). Minimizing beat error is always a good thing to do, and a good first step prior to regulation. However, what counts as "excessive" really depends on the design of the balance and balance cock or bridge.

Newer movement designs usually have an adjustable carrier for the hairspring stud, which allows the beat to be adjusted relatively easily by carefully rotating the stud carrier. With these designs, the beat error should generally be adjusted to 0.2ms or less, at which point it is unlikely to create any noticeable issues.

Older movement designs often have a fixed stud carrier. In this case, the only way to adjust the beat is to rotate the hairspring collet where it wraps around the balance staff (technically you can also rotate the roller table, but this can be difficult to do without completely removing it from the staff, so is not a common approach unless the impulse jewel is way out of alignment). The hairspring collet has a seam, and can be rotated by inserting a small object into the seam and applying appropriate torque. Small screwdrivers are often used for this, although you can get dedicated tools that make the process a bit safer.

This operation generally requires removing the balance from the cock, which gets very tedious and if many adjustments are required. If you're brave, you can, instead, support the balance on a balance tack and maneuver a tool in between the coils of the hairspring to adjust the collet while the balance is still attached. This saves a lot of time, but significantly increases the risk of hairspring damage. Regardless of the exact approach, this adjustment requires application of force in very close proximity to the delicate hairspring, and it only takes one small slip to permanently deform the hairspring in a manner that's nearly impossible to fully correct, so great care and patience is required.

Because discretion is often the better part of valor, when working with fixed stud carriers it is advisable to accept a significantly higher beat error as tolerable. I generally don't attempt to adjust beat error on fixed stud carrier balances unless it's above ~2ms, unless I have reason to believe that it's causing a significant regulation issue (typically not the case in my experience).

Regulation Adjustment Out of Range

Occasionally, you may encounter a watch that seems to be running well, but where you are unable to bring the rate within an acceptable range using the regulator before it reaches the end of its reasonable adjustment travel. There are a few things you can check in this situation, which can often bring the rate back to a point where the watch regulates properly with the regulator near the midpoint of its adjustment range (the ideal scenario). I'll be assuming you're working with a traditional index regulator here, as free-sprung balances are a completely different animal, and also tend not to have regulation issues of this sort.

The first thing to check here is the regulator itself, specifically the alignment of the curb pins and the hairspring. Regulator curb pins are quite delicate, and can easily become bent out of alignment during servicing or handling. Misaligned pins tend to leave the regulator gap either too wide (loose) or too narrow (tight), and can also end up off center to the hairspring so that one pin or the other is placing excessive force on the hairspring. In some cases, kinks or bends in the hairspring itself can cause this misalignment. All of this can significantly impact the rate and throw off the adjustment range.

If you suspect the pins are too tight, too loose, or misaligned, you can use a pair of fine tweezers or a small screwdriver to very carefully and gently bend them into a better position. If the watch has an adjustable curb pin, you can also adjust its position relative to the fixed pin by rotating it slightly. Try to first adjust things so that that hairspring is centered between the pins and makes equal contact with both pins. If you can't do this without moving the pins way out of their natural alignment, you may have a hairspring issue which will need to be corrected first. Once the hairspring is centered, you can slightly tighten or loosen the pins to adjust the rate - the watch will run faster with a tight regulator and slower with a loose one. Bring the regulator arm to a neutral position and try to adjust things so you get close to the correct rate with the arm in that position. You can then make final adjustments as normal by rotating the arm.

One important caution: If you need to bend the fixed pin or pins, go slowly and make very small adjustments. The soft metal of these pins fatigues quickly, and it's easy to break them if you apply too much force, or if you repeatedly bend them back and forth to try to get to the right position. A broken curb pin is not an easy fix, and if you break one you may need to find a new regulator arm, or more likely an entirely new balance cock assembly.

If the regulator or regulator pins seem to be in a good configuration but you are still unable to achieve the desired rate, another possibility to consider is the condition of the hairspring itself. Aside from potential distortions, phenomena like oxidation or work hardening over many years of use can change the elasticity, or modulus, of the hairspring steel, causing its natural rate to alter. The effects of hairspring material changes are generally pretty small and easy to compensate for, but in some cases the effect could be more drastic. It's tough to find replacement hairsprings, short of replacing the entire balance, so if you suspect the material properties of the hairspring are compromised, you may want to first try to compensate by adjusting the balance wheel (see below).

If other approaches fail you can take a look at the balance wheel itself - specifically its overall mass and/or poise. Balance wheels tend not to spontaneously change their mass or poise, but occasionally a balance screw may come loose or even fall out, which will definitely impact the rate. Even if the balance screws are all present and tight, you can still try to adjust the overall rotational mass of the balance by slightly loosening or tightening the balance screws (just make sure to do so evenly so as not to throw off the poise). You can also increase the rotational mass (which slows the rate) using balance washers under the balance screws. Overall, adjusting the balance mass is, IMO, a bit of a last resort, but it can be effective in extreme cases where you have ruled out hairspring or regulator fixes but the rate is still out of range.

Uneven or Chaotic Beat

If the watch exhibits an uneven or chaotic beat pattern on the timegrapher, more often than not it can be traced back to a hairspring issue. Some common problems with straightforward fixes include a magnetized hairspring or a hairspring that is sticking to itself due to dirt or oil contamination. In these cases the balance should be demagnetized and/or thoroughly cleaned to resolve the issue. If I suspect a contaminated hairspring I will usually give the balance a good soak for several hours in clean bench solvent (e.g. hexane or naphtha) to dissolve any residual oils.

If magnetism or contamination are ruled out, the next most likely culprit is an alignment issue causing physical interference with the hairspring during its travel. Misaligned hairsprings can interfere with the balance cock, the arms of the balance wheel, the center wheel (on closely spaced movements), or the regulator retaining shelf. If this interference is severe it will tend to cause a noticeable loss of amplitude, but even very minor or intermittent interference will show up on the timegrapher as an uneven or chaotic signal. Often, these issues will only present when the watch is in specific orientations.

Hairspring interference issues can sometimes be addressed by adjusting the position of the hairspring stud in the stud carrier. Loosening the stud screw, adjusting the stud up or down, then re-tightening carefully can help alleviate interference. More serious or pernicious issues with alignment generally point to a damaged or kinked hairspring. For example, if you observe the hairspring from the side and it is not sitting flat, in a single plane, it may be due to a twist in the hairspring. We'll discuss hairspring corrections in more detail in our guide on Addressing Amplitude Challenges.

There are a few other, non-hairspring-related items to check when diagnosing a chaotic beat pattern. One is the balance pivots. Obviously, if a pivot is broken, the balance will not run properly, but even a slightly bent or damaged pivot can cause issues. Similarly, a cracked, broken, or loose pivot jewel can cause problems that manifest as a chaotic beat. Finally, make sure the pallet fork is moving freely and evenly across its entire range of motion, and that there are no obstructions or damage to the impulse surfaces or pivots.

Inconsistent Rate Across Positions

As the watch orientation is changed, gravity can cause slight shifts in the positions of various components as well as the physical forces acting on pivots and other parts. This changes the overall impact of fritional forces within the movement, leading to variations in rate. Some variation across the different watch positions is to be expected, and proper regulation is really the art of identifying a good compromise adjustment point that causes these variations to balance out as the watch is worn throughout the day. However, if the rate variation is excessive (e.g. more than 20 seconds per day between positions), it may be indicative of an underlying issue that needs to be addressed.

As ever, the balance is generally the first place to look. If the hairspring is misaligned (see above) and physical tolerances are tight, changes in orientation can cause the hairspring to interfere with other components in some positions but not others, leading to inconsistent rates. This is exacerbated if the balance pivots are loose or worn, since this allows the balance to shift more dramatically with changes in orientation. This is also where beat error issues come into play, since a balance with significant beat error may behave differently in different orientations -- particularly horizontal positions (i.e. not dial up or down). Finally, if the watch slows dramatically in horizontal positions, it may be worth rechecking the lubrication of the balance pivots, as there may be excessive friction in these positions if the lubrication is insufficient.

While balance issues tend to have the most direct and dramatic impact on the rate, the other moving parts of the movement are also affected by changes in orientation and can affect the amplitude and rate. All of these parts have some potential to misbehave in certain orientations, but in my experience there are a few more common culprits to consider:

  • Pallet fork: Similar to the balance, if the pallet fork pivots are loose or worn, changes in orientation can cause the fork to shift slightly, affecting its interaction with the escape wheel and overall rate.

  • Train wheels with Cap Jewels: Some movements have cap jewels in the wheel train that are really just for show, and to pump up the jewel count -- they don't actually support the wheel pivots. In other cases, however, the wheels do in fact ride on the cap jewel like the balance. In the latter case, if the cap jewels are loose or misaligned, it can cause rate inconsistencies across positions. Pay particular attention to cap jewels with shock protection, as these can be tricky to release (e.g. when removing the cap jewel for cleaning) and may end up misaligned or damaged when reinstalled.

  • "Above the Bridge" Indirect Drive Center Second Mechanisms: Some vintage movements have center seconds mechanisms that are driven indirectly via an intermediate wheel mounted above the train wheel bridge. Typically this wheel is press-fit onto an extended 3rd wheel pivot and engages with a separate center second pinion. It's easy to damage these wheels when removing them, especially when proper wheel removal tools aren't employed, and intermediate wheels that are slightly taco-d and don't sit completely flat are not uncommon. It can also be difficult to judge exactly how far to press the wheel down onto the extended pivot. This is an issue because, in order to keep the movement as thin as possible, the tolerances on these mechanisms are often quite tight. The upshot is that, more than once, I have noticed these mechanisms starting to rub and affect the amplitude and rate, particularly when the watch is placed dial-up.

Inconsistent Rate Over Time

If the watch's rate oscillates significantly over time while in a fixed position, it's likely that one of the train wheels has an asymmetry or other issue that is causing periodic changes in amplitude as the wheel rotates. You can often identify the problematic wheel by observing the amplitude pattern on the timegrapher and comparing its periodicity to the rotation rates of the various wheels in the train. For a typical 18,000 vph Swiss movement, these rates are:

  • Escape Wheel: ~3 seconds

  • 4th Wheel: 60 seconds

  • 3rd Wheel: 450 seconds

  • Center Wheel: 3600 seconds (1 hour)

  • Mainspring Barrel: ~7-8 hours (varies)

Once identified, the potential problem wheel(s) should be inspected for issues such as bent, broken or dirty teeth, a bent pivot, or a misaligned jewel. Addressing these issues can help stabilize the amplitude and rate over time.

"Stair Steps" in the Rate (Overbanking)

You may occasionally observe a watch with high amplitude (generally well over 300 degrees) that exhibits "stair step" behavior in the rate measurement on the timegrapher. This is characteristic of overbanking, where the balance is rotating so far that the impulse pin strikes the outside of the pallet fork horns at the peak of its swing. This creates an acoustic signature that the timegrapher interprets as another beat, leading to a huge, instantaneous increase in calculated rate that creates the stair step pattern. Very mild and infrequent overbanking is generally not a big deal and won't significantly affect the performance of the watch, but if it's happening frequently it can lead to erratic timekeeping or even damage to the escapement.

To address this issue, you need to reduce the amplitude of the balance. The most obvious and direct way to address this is at the mainspring, by reducing the maximum mainspring tension. In automatic movements, excessive amplitude is sometimes a symptom of poorly lubricated mainspring barrel walls which are allowing the spring to build too much tension before slipping, in which case revisiting your application of braking grease is a good idea. For manual wind movements, you may need to try a slightly weaker mainspring.

Another place to check is the pallet fork and banking pins. If the banking pins are misaligned or the pallet fork is damaged, it can cause overbanking even at otherwise-acceptable amplitudes.

Conclusion and Additional Resources

Regulating a mechanical watch is generally a straightforward and useful skill, even for watch owners who don't plan to do extensive watch servicing or restoration themselves. Of course, if you read the Troubleshooting section above, you can see that there is definitely a potential for things to descend down a very deep rabbit hole if the movement you are trying to regulate isn't in great shape, at which point it certainly helps to have a deep engineering understanding of how the watch movement functions. However, with a good grasp of the basics and some patience, most watches can be regulated to an acceptable level of accuracy without too much trouble.

For those looking to deepen their understanding of watch regulation and related topics, I recommend exploring additional resources such as: