Watch Regulation has come a long way in the 50 years ever since the Etachron regulation system came about.

If you’re having problems regulating a watch that uses the Etachron system, more than likely it’s because you’re not adjusting it before you start trying to regulate the rate. Watch Regulation isn’t hard, but information is king.

First, I’ll show you how to remove and install a new balance wheel and hairspring. Then I’ll take you step by step through the entire process of adjustment that sets up the regulator to be able to adjust the rate for multiple positions.

Important: When available, we use affiliate links and may earn a commission!

What’s different about the Etachron  Regulator for Watch Regulation?

Well, around 1976, ETA introduced this new two-part regulator system that replaced the adjustable regulator pins that have pretty much been used forever for watch regulation.

This was a big advancement for regulators, and they did it by only changing two small things.

The Stud Block

Instead of holding the hairspring to the stud block with a tapered pin, the hairspring was now permanently epoxied to the block.

Then instead of the stud block being held in a fixed position, the stud block is held under tension in a fork slot, which allows the hairspring’s position to be easily adjusted.

Glued Hairspring  Stud
Glued Hairspring Stud

The Regulator Block

In the Etachron system, the regulator block has two fixed pins, which keep the pins at a 90-degree angle to the hairspring.

Regulator Block
Regulator Block

This new regulator block is also held in place under tension in a retaining fork.  This allows the entire block to be rotated, closing the gap between the hairspring and the regulator pins.  This eliminates the need to bend the pins themselves.

Mandatory Conditions for Watch Regulation

Now like always, to be able to regulate any movement:

  1. The movement needs to first be properly serviced and lubricated
  2.  The movement should be free of all magnetism
  3.  The gear train must be running freely
  4. All end and side shakes should be normal
  5. The hairspring should be flat and centered on the collet
  6.  The movement should be in beat
  7.  The escapement needs to be operating correctly
  8. You should have a consistent amplitude of at least 270 degrees in the horizontal positions.

Replacing the Balance Complete

Removing the hairspring and balance wheel is straightforward. There’s just a couple small things that you need to remember.

First, you’re going to always want to do it with the balance cock mounted to the bridge.

The second thing that you need to do is to put the regulator pins in the correct position to remove the hairspring.

Straighten the Regulator Block

As you’re looking at the hairspring regulator, you can see that it’s tilted slightly towards the hairspring stud. What we want to do is straighten it out so that the gap is parallel to the hairspring once we flip it over.

They have tools to make these adjustments, but in this particular case, you can just use your tweezers. We’re going to slowly turn it until the regulator pins are at their widest point.

When you’re looking at the top, you want this running straight up and down.

Straighten Regulator Block
Straighten Regulator Block

Remove Hairspring Stud from Fork

Now we need to remove the hairspring stud from the fork that holds it. They have tools to remove this, and I’d bought one, but the first time I used it, it broke.

My go-to method ever since, not looking for any tools to help me out here because you really don’t need one for this.

These two forks are under tension. What we need to do is get something in this area that we can just push the stud out.

Free Hairspring Stud
Free Hairspring Stud

For this I find my bronze tweezers work the best. What we’re going to do is just put one tine into the gap and then we’re just going to slowly twist it until the hairspring stud pops out.

Try to do this without putting any pressure down on top of the stud arm. You just want to give it a nice gentle twist and the hairspring stud is free.

Removing the Balance Cock

I like to start by just loosening the balance cock from the main plate and then we’re going to pick up the balance wheel in the cock together.  Remember we don’t have the spring attached to it and we can just pick it up and flip it over on its back.

Picking up Loose Balance Wheel and Cock
Picking up Loose Balance Wheel and Cock

With the balance cock removed from the watch, the next thing we need to do is get the hairspring out from between the little slit between the two regulator pins. I like to use my bronze or brass tweezers.

We’re just going to grab the hairspring and gently lift it off.

What if the Hairspring wouldn’t lift out?

Now when we look at the two regulator pins, you’ll see that the opening at the bottom is just wide enough to get the hairspring out.

If you are struggling a little bit to get it out, first make sure that you’re pulling it straight up. In order to separate these to make it wider, you’ll need to use a razor blade to spread it open a little bit. This means you’ll also need to close it back as well and it would really be best if you didn’t have to fool around with that at all.

Be patient, make sure that you’re pulling straight up on the hairspring gently and it should slide right through that groove at the bottom of the regulator pins.

Replacing the Balance Complete

When you’re replacing a balance complete, which as you probably already know is the balance wheel and hairspring. These are replaced as a set.

If you have a movement with the Etachron regulator and you have a damaged hairspring, you’re going to need to replace both the hairspring and the balance wheel.

2824 Balance Complete
2824 Balance Complete

The hairspring and balance wheel are poised together at the factory as a set and this is what you need when you go to replace these. You want a set that has been vibrated together.

Poising Cutout

When you look at a balance wheel after it’s been poised with the hairspring, you’ll notice that there’s a slight groove cut on the underside of the balance wheel.

Balance Wheel Poise notch
Balance Wheel Poise notch

During the poising operation, it was determined by the factory that this area of the balance wheel was heavier than the rest of the areas around the balance wheel. This is where a little bit of material was cut away from the underside of the balance wheel to make the balance wheel balanced.

The amount of material that’s cut away from this balance wheel, its location on the balance wheel is all factored on this hairspring.

Reinstalling the Balance Wheel and Hairspring

Now to reinstall the new balance wheel, we’re just going to set it roughly in place where it’s going to be.

We’re going to hold down the bridge and just drop the hairspring through the groove. Now we’re going to go in and we’re going to pick up both the balance wheel and the cock as one piece, flip it over, and  put it in position on the movement. 

At this point I don’t care about the impulse jewel being in the fork slot. All I really want to do before I put the screw in is I want to make sure that my pivots are in the pivot holes. When I put my screw on, I don’t bend or break the pivots

Installing the Hairspring Stud into the Fork

I can now move the hairspring stud into it position in front of the fork.

With the hairspring stud in position, I’m just going to take the back side of my bronze tweezers and I’m going to lay them on the side of the hairspring stud at a 90 degree angle.

Holding the tweezers in my right hand, and with my left index finger, I’m just going to slowly apply pressure to the stud until it snaps in position.

With the hairspring stud secured in place, now we can remove the balance cock and reinstall

it properly.

Watch Regulation: Adjusting the Etachron System

1.      Correct Any Beat Error

The first step in adjusting the Etachron system is to put the watch in beat.  I’ve given the movement a full wind and now I’m just going to make some small adjustments until we can get the beat error to zero.

In watch regulation you shouldn’t really obsess too much about beat error. As I’ve talked about before, beat errors under 1.0 milliseconds do not affect the timing of the watch.

If you’re working on an older vintage watch where you must turn the collet to adjust the beat error, if you can get it down to 0.4 or 0.5 milliseconds, I would be happy with that.

Sometimes you get lucky, and you can get it to 0 or 0.1 milliseconds. Just get it as close to 0 and as far away as 9 as you can get.

In modern movements like this, adjusting beat error is simple because you don’t have to take the balance out to change it or adjust it.

Other Causes of Beat Error in a Mechanical Watch

Since we’re talking about beat error, just be aware that there’s many other things that could cause a watch to be out of beat.

  1. You could have a sloppy pallet arbor.
  2. You could have a loose roller jewel.
  3. A loose pallet stone or a loose
  4. A Loose End Stone
  5. A loose regulator pin
  6. A loose banking pin
  7. One of the most common causes of beat error in older vintage watches is the hairspring collet is just loose.
  8. Maybe one of the harder things to detect is the guard pin rubbing on the safety roller.

Now that the watch is in beat, we’re going to go ahead and let down the power to the mainspring until our balance wheel stops.

2.      Set the Micro Adjustment Screw

The next thing we want to make sure is that our micro-adjustment screw is pointing straight up to the middle.

And if you haven’t done it already, you want to make sure that the regulator pins are in the fully open position, which you can tell by looking at the top of the regulator stud.

Watch Regulation: Micro Adjustment Screw
Micro Adjustment Screw
Watch Regulation: Regulator Block Is fully Open
Regulator Block Is fully Open

3.      Coil Spacing

Step one in making these adjustments is we want to look at the current spacing of the coils of the hairspring. You’ll just have to peer in between things so that you can see, and what we’re looking for really is we’re looking for any bunching.

That will basically tell us that the hairspring is not concentric.

4.      Center the Hairspring in the Regulator Block

Now we want to center the hairspring in between the regulator pins. Looking at the hairspring in between the regulator pins, I think it’s obvious when you’re looking at it at this angle to see that it’s not centered in between the regulator pins.

It’s not tight up against the inside pin, but we need to adjust it so that it starts off in the middle.

Watch Regulation: Hairspring that is not Centered in Regulator Block
Hairspring that is not Centered in Regulator Block

If you’re not sure why that’s important, the video that I did previous to this one was about the relationship of the regulator pins with the hairspring.

Etachron Adjustment Tool

To make this adjustment, there is a special tool that you’re going to want to have. You can turn the regulator block with a pair of tweezers, but this is an incredibly fine movement, and it’s going to be very hard to do it effectively with a pair of tweezers, especially depending on the angle which you’re trying to see the actual hairspring.

Etachron Watch Regulation Tool
Etachron block key

The way you adjust the hairspring to the middle of the regulator pins is by inserting this tool on top of the hairspring stud. Then we’re going to turn the tool very slowly and carefully until the hairspring is in line with the center of the regulator pins.

Watch Regulation: Hairspring Centered in Regulator Block
Hairspring Centered in Regulator Block

     5. Checking the Regulator Curve

Now that we have the hairspring centered in the regulator block, the next thing we want to check is the regulator curve here.

Move the regulator arm along the regulator curve from one end to the other.  Our goal is that the hairspring doesn’t move. If the hairspring does move, that means that this curve is out of shape and will need to be adjusted.

To check this, we’re going to move the regulator arm from one end of the regulator curve to the other, and what we’re going to do is focus on the coils.  What we’re going to look for is to see if the spacing between those coils’ changes.

Coils Before
Coils Before
Coils After
Coils After

Well, clearly, we can see that the coils got smaller, so that means this regulator curve needs an adjustment.

Let’s go ahead and do that.

6.      Locating the Hairspring Problem

Now to find the problem with the hairspring, I’ve went ahead and taken the balance wheel back out of the movement.  When we look at the spacings on the coil, we can clearly see in the lower half right here where the coils are closer together than any other place on the hairspring.

Problem In Hairspring Coil
Problem In Hairspring Coil

The first thing I would probably do is make sure that it’s not magnetized. This is a pair of carbon steel tweezers, and you can clearly see that it is not magnetized, otherwise the hairspring would be sticking to the tweezers.

Here lies at least one problem with the hairspring that we need to correct.

In theory, hairspring corrections are straightforward, as there’s only two rules that you need to be aware of.

When the spacing of the coils is incorrect, the correction point is 90 degrees away from the problem area.

Hairspring Correction Point
Hairspring Correction Point

We’re going to needle it out, or we’re going to bend it out a little bit to correct this gap.

Watch Regulation: Tools for Hairspring Work


When we’re doing needling work, the shape of your tweezers makes a lot of difference in how easy it is to grab the hairspring itself.

I think you’ll find straight tweezers are a little bit awkward. I prefer using a curved pair of tweezers.

Hairspring Tweezers
Hairspring Tweezers

This one is specifically for holding hairsprings, but some people prefer just curved pair of tweezers.

Needling tool

Now beside the tweezers, you also need a needling tool. You can find needling tools for hairsprings on websites like eBay, and I think you can even buy new ones, but this is one that I made myself.

It is essentially just a sewing needle that I heated up the end so that I could put a bend in it and epoxied it into a piece of peg wood.

Needling Tool
Needling Tool

Then I just shaped the end of the needle on an Arkansas stone to thin it out, and then just polished it with a Polinum, just a high gloss polish on a hard felt wheel.

So that’s really all there is to that.

7.      Needling the Hairspring

Looking at our hairspring, here’s the point where the coils are too close together, and we’re just going to go back 90 degrees, grab our hairspring, and we’re just going to lightly bend it out.

Needling Hairspring
Needling Hairspring

What’s important here when you’re making these types of corrections is that you want to make very small corrections at a time. Don’t try to correct the bend in one shot. Make small little corrections until you get it where you need it.

Now we’ll go ahead and install the hairspring back into the movement, and we’ll check our work.

Checking the Hairspring Adjustment

All right, so we have the balance wheel reinstalled back into the movement. I’ve moved the regulator to the bottom of the regulator curve, and now we need to center the hairspring again.

Just as a general rule, the gap that we’re looking for between the hairspring and the regulator pins is about the thickness of the hairspring itself.

 I’m looking at the hairspring between the regulator pins, what I’m looking for is to just try to get the gap even on both sides, which is about the width of the hairspring.

Now we’re going to move the regulator arm up the regulator curve, and we’re looking for is to see if the width of the coils right here change as we move up the regulator curve.

Adjusting the Regulator Block

Closing the Gap

Now that we have the regulator curve centered on the pins along the length of the regulator

curve, now we’re going to bring the regulator back towards the middle. What we’re going to do is close the gap by turning the key on the top of the regulator pins to close the gap between the hairspring and the regulator pins.

You want to do when you make this adjustment is to turn it towards the hairspring stud.

The key here is we do not want the regulator pins to bind on the hairspring. This is going to be a micro adjustment of the regulator pins themselves.


The Etachron Regulator make watch regulation pretty simple.

We started off by adjusting the hairspring so that it was centered in between the regulator pins.

Then we checked the travel of the regulator pins up along the regulator curve, which revealed that the curve was not concentric, that the pins were now pulling on the hairspring, causing the coils on one side to bunch up.

We then made another series of adjustments to the coils of the hairspring to correct the errors of the spacing between the coils.

Now once that adjustment was made, we reinstalled the balance and then we rechecked the travel of the regulator arm along the curve, verifying that no matter where the regulator pins are along that curve, that the hairspring will still be centered and therefore it’s going to act the same no matter whether you’re in a horizontal or vertical position.

Then we made one final adjustment to close the gap between the hairspring and the pins.

This entire process is what is known as adjusting, which will always be done prior to regulating the movement for rate.

No matter whether it’s a watch with the Etachron system or if it’s a 100 year old pocket watch, the process for watch regulation is basically going to be the same.