For new watchmakers, removing and replacing Seiko Diashock springs might seem like one of those things that’s just better left alone. Maybe you have an Incobloc or Kif Spring that needs to be removed.  

If the thought of removing and replacing shock springs in order to clean the end stones is one of those jobs that you just keep putting off because you don’t want to risk either losing or breaking the spring., then this post is for you.

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Why it is Important to Remove Shock Springs

When servicing a movement, beings able to clean and relubricate the end stones is pretty important. Which means removing the shock springs is necessary.

Cleaning and lubricating the end stone for the balance pivots is not only necessary. It’s critical for the balance to be able to have equal amplitude in the dial up and dial down position.

If the horizontal positions aren’t equal or at least very close to being equal you’re not going to be able to regulate the watch.

Tools for Removing Shock Springs

Tweezers

These are my carbon steel Dumont 3C tweezers. I keep these dressed to an extremely fine tip, like a needle. I also keep them polished and clean them regularly.

Bronze Tweezer Comparison
Bronze Tweezer Comparison

The second pair of tweezers that I use are Bergeron bronze tweezers. If you do not want to spend the money for bronze, brass tweezers will also work fine.

Reshaping Brass Tweezers

The problem that I originally had with these bronze pair is that they were too big and clumpy at the tip. I ended up filing down the tip of the tweezer to match the profile of the Dumont 3C’s and now these are my go-to tweezers.

If you are not familiar with dressing or shaping tweezers, you can check out this post I did.

I mean I still love these Dumont’s. I’ve been using them so long it’s hard not to reach for them, but I find myself going to the bronze tweezers more and more

Needling Tool

The needling tool is just a sewing needle that’s been sharpened and polished.

Needling tool
Needling tool

I drilled a hole and inserted it inside a 5mm piece of peg wood that I’ve glued inside. I use this tool for all types of things but they’re really well suited for working on shock springs as well.

Best Practice’s when Removing any Shock Spring

There are a few best practices that I would recommend that you follow anytime you’re working on shock springs or jewels.

Work on an Uncluttered Bench

The first is to work on a bench with only what you need to do the job on the bench. No clutter

If a spring or jewel jumps off the movement, the less clutter you have on your workbench, the fewer things that spring or jewel has to hide behind.

Keep a Clean Work Surface

Always do assembly work on a clean bench.

You want to make sure that your surface has been wiped down clean. I just use Windex and paper towels to clean my workbench. I also clean my work mat to make sure that its dust, dirt and grit free.

No Distractions

Make sure there’s no distractions around you that might break your concentration while you’re actually working with the jewels and the springs.

The last thing you want to have to do is get up from your bench leaving unfinished work or unsecured springs on the bench. This is just a recipe for disaster.

Stay Focused

Be very mindful and stay focused on that jewel while the spring is open. You always want to know where it is.

Many of you already know that these springs can get lost just like that. Concentrating on what you are doing is especially important.

Pro Tip

I like to keep a little metal tray and a clean piece of Rodico ready off to the side on the bench. If I have to pick up a jewel or spring, I can just use the Rodico and drop it in the tray and then move it out of my reach.

The last thing you want to do is put a jewel or spring down in front of you and then accidently have your hand or arm touch it. The spring or jewel will stick to your body and before you realize it will be gone.

Removing and Replacing Incobloc Springs

One of the biggest problems that people seem to have with Incobloc springs, is the spring coming out of the jewel block and they can’t get it back in.

Removing the Spring

Start by unclipping one side of the spring by gently pressing on the spring arm until it releases from the block. Gently push on the other side until the second side is released.

Releasing Incobloc Spring
Releasing Incobloc Spring

It’s at this point where things can go a little bit awry. What you want to do is just pull the shock spring straight back. Do not let it get sideways.

With the Incobloc Spring open and pulled back, you can remove the chaton and end stone to clean and lubricate them.

Reinstall the Chaton and Spring

To reinstall the Incobloc spring, make sure to push the spring from the middle of the shock spring.

To close the spring into the block, simply take your tweezer, lightly push down until the first side goes into the jewel block and then just repeat on the second side.

Closing Incobloc Spring
Closing Incobloc Spring

By giving the spring a little bit of downward pressure while pushing sideways the arm will slide right into the groove in the block.

Removing and Replacing KIF Style Springs

Removing Single Notch Style

The second spring we have is a Kif style Spring. These types of springs will have three little fingers that hold the spring into the jewel block.

To remove the spring, I like to use two pairs of tweezers. I keep one tweezer point inside the center of the spring to keep it from flying away while using the other one to turn the spring.

Removing Single KIF Style Spring
Removing Single KIF Style Spring

Once two of the springs fingers have been released, the spring will be free. To pick up the spring, I simply use a piece of Rodico. Lightly touch the spring to pick it up, put it in a tray and move the tray to the other side of the bench

Replacing the Single Notch Style

To replace the spring, we’re simply going to pick up our Rodico that has our spring attached to it. I’m going to bring it over and just release it from the Rodico with my tweezer.

I like to work in a clockwise direction so I want the first pin to be in the groove in the block.

You can see that it’s in the groove and I want the second pin to be right there in the notch. I’m going to press it down and then slowly twist it clockwise.

Installing Single Style KIF
Installing Single Style KIF

I’m going to use the needle to turn the spring. With two pins in the groove of the block, simply rotate the spring. Keep the needle or the tweezers inside the spring until the third pin is in position.

Push down on the third tab and then rotate the spring with the needle. With all three fingers in position, just rotate the spring so that the curved part of the spring is lined up with the notch.

How To Remove & Replace 3 Notch Style KIF Springs

For the next KIF and Seiko Diashock springs, you are going to want to have a tool to aid you while you’re reinstalling the springs.

This is a vintage set of shock spring twisters that I have. You can still buy these vintage sets as well as new sets but I like to make my own.

Making A KIF Tool From Peg Wood

My preferred method is to make the tool out of a piece of peg wood. I if you don’t have peg wood you can also use a toothpick, basically does the same thing.

In order to make the tool we want to have some idea of how big of a hole we want to bore in the end of our peg wood. To do that we’re going to take a measurement with our digital caliper. If you don’t have a digital caliper now you can do it by eye but digital calipers are one of those tools that you’re going to definitely need to have in watchmaking.

Digital Calipers

When I was looking to upgrade to digital calipers, I did a ton of research, talked to a lot of other watchmaker friends that I know, because I wanted accuracy, but I didn’t necessarily want to spend $500 on a set of calipers.

I ended up purchasing are the Mitutoyo Digital Caliper. Mitutoyo is a Japanese brand and they make really high quality calipers.

How Accurate is the Mitutoyo Digital Caliper

To evaluate their accuracy, I am using a set of pin gauges. If you’re not familiar with pin gauges, these are precision ground rods that are accurate within a thousandth of an inch.

Pin Gauge
Pin Gauge

To check the accuracy of this caliper I’m going to use a pin gauge that is 0.60 of an inch. These calipers work in either a millimeter or inches so I just insert the rod into the caliper and you can see that it’s showing a measurement of 0.06 which is the exact size of this particular pin gauge. So, these calipers are perfectly accurate.

Checking Accuracy of Calipers
Checking Accuracy of Calipers

Measuring Hole size for the Tool

The first thing we want to measure for is about how big of a hole we want in the end of the peg wood. We want the tool to press down on the edges of the shock spring. If we leave the end of the peg wood flat all we are essentially going to do is push down on the end stone which isn’t going to do anything. We need to hollow out the end of the peg wood a little.

First you want to figure out how big the tip of the tool should be. I’m going to do is get a measurement of approximately how wide this jewel is so we know what size hole to drill.

Measuring Tool Hole Size
Measuring Tool Hole Size

Drilling the Hole

We could see our measurement is 0.9 mm. One way to drill the hole would be with micro drill bits.

With the bit installed into a pin vise, we are going to center the bit into the center of the peg wood. Then we’re going to just slowly just go down into the peg wood about a half a millimeter

Drilling Hole with Micro Drill Bit
Drilling Hole with Micro Drill Bit

The difficulty in using a drill bit like this is that it’s almost impossible to get the drill bit the center in the peg wood. It will be easily corrected in our next step when we start shaping the tip end.

Using the Horotec MSA 22.577A to Drill a Hole

The method I typically is with this set of cutter s from Horotec.

Horotec Tool Tip
Horotec Tool Tip

This set has a very fine tipped auger with a very fine point which allows you to really get in and center the cutter. You just slowly twist it to cut the hole.

Measure for the Width of the Tip

Once we have the hole in the end of the peg wood, we need to see how wide we want the outside of the peg wood tip to be. In this case it looks like it is about 1.2 millimeter.

Measuring KIF Tool Tip Size
Measuring KIF Tool Tip Size

I’m using a # 4 cut file to slowly reduce the end of the peg wood until we get it down to the 1.2 millimeters. If your holes off-center a little bit you’ll need to compensate for that. You may have to bring down one side a little bit more than the other.

Just keep checking it with your loop and keep reducing it down until the tip measures 1.2 millimeter.

Removing the KIF Spring

This KIF spring still has 3 fingers on it like the other one, but now the shock block has 3 notches instead of one.

Taking them out is straightforward. I’m going to use my needle keeping it on the end stone as I turn the KIF spring so there’s no chances of it flying away. Simply turn the spring until it is free.

Installing the KIF Spring

To install this KIF Spring you must lay the spring in position with one finger over each notch. Then push down the spring with equal pressure so that all the fingers bend into the notches while twisting the spring. Easier said than done.

With the spring in position, we are just going to take our tool we just made and insert it on top of the jewel. I am going to push down and give it a little twist clockwise. Make sure that all the fingers are in the groove in the block.

3 Notch KIF Ready To Install
3 Notch KIF Ready To Install

Now that we have the fingers from the spring in all the notches, we just want to turn the spring a little bit more so that the three fingers are centered in between the grooves. To do this, we’ll just use our needle and our tweezers and we just give it a slight turn and now each finger is centered in between these notches

Removing and Replacing Seiko Diashock Springs

The last spring, we are going to work on is going to be Seiko’s Diashock and for that we’re going to need a little different tool. Seiko’s Diashock seems to be one of the types of shock springs that really gives people fits.

One of the things that will make it a lot easier to work on is if the balance isn’t moving. If the Chaton and the end stone is jumping around as the balance wheel is spinning, it’s going to make it really hard to install the spring.

Removing the Diashock Spring

Removing it is really straightforward so we’re going to use a needle and a pair of tweezers the needle is going to act as our safety so we’re going to do most of the turning with our tweezer. Remove it with a little piece of Rodico, pick it up and put it in a tray.

Making the Tool for the Seiko Diashock Spring

The tool that we are going to make to replace it is actually pretty simple. I’m using a piece of four millimeter peg wood.

The first thing we need to do is reduce the width of the peg wood so that it fits in this notch on either side of on either side of the block.

Sizing Pegwood for Seiko Diashock Tool
Sizing Peg wood for Seiko Diashock Tool

I find it the easiest to just to use a razor blade to reduce the width. What we want to do is reduce it so that it fits in the notch of the block. We’re going to use this tool to push down on the spring on either side so that it goes into the groove in the block.

Cutting a Groove in Our Diashock Tool

Now that our piece of peg wood is flat and sized to the spring slot, we need to remove some material just so that when we’re pressing down on the spring, the peg wood is not pushing down on the end stone.

Notch Cut in Peg Wood for Seiko Diashock Tool
Notch Cut in Peg Wood for Seiko Diashock Tool

I’m going to use a three-sided file, centering it the best I can I’m going to remove as much material as I need in order to be able to clear the end stone.

Replacing the Diashock Spring

Once we replace the chaton and end stone, we brin in our spring and use our needle to gently release it from the

Rodico. I’ll just position the spring, so the two ends of the spring are inside the cutouts.

With our tool we’ll gently place it on top of the spring, push down and give it a little twist so that the spring enters into the groove inside the block.

Installing Seiko Diashock Spring with Tool
Installing Seiko Diashock Spring with Tool

With the spring started inside the groove now we’re just going to take our tweezer and our needle tool and we’re just going to slowly rotate it around until the spring is fully seated in between the two notches.

Frequently Asked Questions

What does Diashock mean?
Seiko Diashock
Seiko Diashock

Diashock is a type of Balance shock absorption system used in some Seiko watches today.


It was developed by Seiko in the 1950s and is designed to protect the Balance Wheel Pivots from shocks and vibrations.
The system uses a specially designed spring to absorb the impact of sudden shocks. It protects the delicate components of the watch movement from damage.


The term “Diashock” is a combination of the words “diameter” and “shock”. It is referring to the system’s ability to protect the movement’s delicate balance wheel, which has a small diameter, from shock.

How does Seiko’s Diashock work?

Seiko’s Diashock is a system designed to protect the watch movement’s balance staff and jewels from damage caused by shocks and vibrations.
The Diashock system features a Block, a chaton, an end stone and a spring.
The Block is mounted into the balance cock and main plate. It is the container that holds all the components of the shock system together.
The Chaton holds a fixed jewel that the balance pivot passes through. It also has a recessed area that holds the end stone.
The End stone fits into the top of the Chaton and is where the balance pivot spins on when the watch is in the horizontal positions.
The Shock spring fits over the top of the end stone holding the chaton and end stone in place.
When a shock or vibration occurs to the movement, the shock spring absorbs most of the impact reducing the force of the impact on the balance staff and jewels. This helps to prevent damage to the delicate components of the watch movement.
The Diashock system is an important feature of many Seiko watches, particularly those designed for sports and outdoor activities where the watch may be subjected to rough handling and impacts. By protecting the balance staff and jewels from damage, the Diashock system helps to ensure the accuracy and longevity of the watch movement.

Conclusion

Cleaning and lubricating end stones is crucial in service work. It ensures that the balance can maintain equal amplitude in both the dial up and dial down positions.

Home Watchmakers avoid this task due to the risk of losing or breaking the shock spring during removal and replacement.

I included some tips and tools for safely removing and replacing shock springs. These are basic tools you have and some easy to make spring installation tools.

I have included some best practices for working on shock springs, such as working on an uncluttered and clean bench, avoiding distractions, and staying focused on the task at hand.

With the Tips and tools provided in this post, you can now remove and replace most of the shock springs you will run into in vintage watches.