With a primary function to protect the watch face from damage and allow clear vision for timekeeping, the crystal is one of the most important elements of a timepiece. Fitting or replacing a watch crystal is a relatively simple process, however, since crystals come in a variety of shapes, designs, and sizes, there are many different ways to install them. A watch press is most commonly used for crystal installation, but again, there are a variety of different types of watch press. Different tools are required for different watchmaking tasks, but amongst all that, a little bit of personal preference is also part of the mix. To help you get started with your crystal installation, this guide to watch presses and tips for crystal installation will help you with this important watchmaking task.
- What is a Watch Press?
- Types of Watch Presses: Lever vs Screw-down Presses
- What is a Crystal Lift?
- Different Types of Watch Crystal
- Different Types of Crystal Fit
- Choosing the Right Press Dies for Different Cases: Matching Tools to Crystal Shape
- Safely Installing a Domed Crystal: Tips to Avoid Cracks or Misalignment
- The Ultimate Guide to Watch Presses and Crystal Installation Conclusion
- The Ultimate Guide to Watch Presses and Crystal Installation FAQ
What is a Watch Press?
A watch press is an essential tool that every watchmaker should have in their toolkit. Also known as a ‘case back press,’ a watch press is designed to secure snap-on watch case backs and press crystals in place. It applies a controlled pressure to ensure a tight and secure fit, essential for preventing damage to the inner workings of a timepiece. By using the watch press, you can rest assured that the watch will not be damaged during the installation process.
A typical watch press consists of a base and multiple dies designed to accommodate a variety of different case backs and crystal sizes. Once the correct die is selected, the watch crystal or case back is inserted into the die before the press applies pressure for accurate installation.
Using a watch press is crucial for proper watch repair and maintenance, ensuring that crystals are installed correctly to guarantee water resistance and protect the watch’s delicate components.
Types of Watch Presses: Lever vs Screw-down Presses
There are multiple different watch presses that a watchmaker can use to perform the task of crystal installation. The most common types are lever presses and screw-down presses, but if you are a newbie to watchmaking, it can be unclear which to choose.
Lever Watch Press
As the name suggests, a lever watch press uses a lever mechanism to install case backs and crystals. The watch press features a metal base with a lever arm, which, when pressed down, applies a controlled amount of pressure to the die that creates the secure fit of the crystal. They come with a variety of dies in various sizes that are both flat and recessed to accommodate a range of crystal shapes and sizes. Most operate face-down, allowing the watchmaker to carefully and easily monitor the process and ensure that the alignment is correct.
Screw Down Watch Press
A screw down watch press performs the same task as a lever watch press but functions in a different way. The design uses a screw mechanism to apply the right amount of force for crystal installation, allowing for a controlled and even distribution of force. It works in a similar fashion featuring an accompanying selection of dies in varying sizes, however, the handle is then twisted rather than pressed to ensure the tight seal of the watch crystal.
Lever Press vs Screw Down Press
In terms of the basic functionality of each press, both a lever press and a screw-down press perform the same job and perform it well. However, there are a few notable differences between the two. Firstly, a screw-down press generally offers more control and precision. They are great for difficult crystal installation or when a secure fit is of the utmost importance, such as when water resistance is crucial. It is important to note that you need to ensure not to overtighten when using a screw-down press, as this can damage the crystal. They also take longer to operate.
In contrast, a lever press is typically faster and easier to use, adding convenience to this watchmaking task. They are useful in watchmaking workshops when there are frequent crystal installations. A lever press is usually more affordable than a screw-down press, making it a great starting press for newbies just investing in their watchmaking toolkit. Unfortunately, they are not suitable for every type of crystal, particularly those prone to cracking.
It is recommended that beginners and those who require efficiency take advantage of a lever presses ease of use. However, for watchmakers who require precision and have the benefit of time, you cannot go wrong with a screw down press.
What is a Crystal Lift?
As an alternative tool to a watch press, a crystal lift can also be used for crystal installation. While not suitable for all types of watch crystal and fit, a crystal lift has its uses and a place in your watchmaking toolkit. Designed specifically to remove and install acrylic tension-fit crystals, it works by gently gripping the edges of the crystal and compressing it, allowing the crystal to be lifted out of or inserted into the watch case with damage. It is particularly useful for vintage timepieces with domed acrylic crystals or when a watch press is deemed impractical. It is an essential tool for watchmakers working with acrylic crystals, ensuring damage-free crystal installation.
Different Types of Watch Crystal
Just like there are different types of watch press, a watchmaker will encounter different types of watch crystal throughout the watchmaking journey. Crystals come in a variety of shapes, sizes, and types, all of which require slightly different installation techniques.
Acrylic Crystal
An acrylic crystal is a plastic material that is highly regarded for its shatter resistance and high affordability. Commonly found in entry-level watches that demand a lower price tag, acrylic crystals are regularly encountered early on in the watchmaking journey when practicing on less valuable timepieces. Although they offer great shatter resistance, they are more prone to scratching than other types of crystal. Acrylic crystals are typically glued into place or have a compressed style that requires installation with a crystal lift rather than a watch press. Older methods of watchmaking also utilize a foot pedal press for an acrylic crystal with a plunger to install the crystal, and an acrylic crystal is the only crystal type that can be used with a foot pedal press, thanks to its shatter resistance and durability. Alternatively, an acrylic crystal with a domed design requires a tension ring or comes as an armored crystal.
Mineral Sapphire Crystal
Mineral and sapphire crystals are similar in design but offer different properties. More scratch-resistant than plastic, a mineral crystal is the perfect stepping stone between an acrylic and a sapphire crystal. Heat or chemically treated to prevent scratches, mineral offers more aesthetic benefits than acrylic without the price tag of sapphire.
The most premium material, sapphire crystals, come with a higher price tag but also offer a more luxurious aesthetic and feel, typically used in high-end timepieces. Although they are more fragile and susceptible to damage, they are less likely to scratch, which is ideal for the daily wear of timepieces. Due to a higher index of refraction, a sapphire crystal is more reflective than a mineral
Different Types of Crystal Fit
In addition to different types of crystal and watch press, there are also different types of crystal fit that all have individual methods of installation.
Friction Fit
This is the type of fit used for almost all mineral and sapphire crystals, regardless of whether the crystal is flat or domed. An L-shaped gasket is used to bridge the gap between the outer edge of the crystal and the inner edge of the case for an optimal fit. It is important to ensure your gasket is the appropriate size, and a watch press should be used for this type of crystal installation. Although you can use both types of watch press to insert a plastic seal crystal, it is advised to use a screw-down press for more precision. With this type of fit, there is a very obvious click when the crystal is in position, a great indicator to stop pressing to avoid overtightening. The gaskets typically have a one-time use, and although you can risk using them again, they will never seal quite the same.
Tension Ring or Armoured Crystal
Some crystals require a tension ring for installation, and some come with a small, beveled ring already inserted at the base. If the ring does not come already built into the crystal, it must be fitted on the crystal before the crystal is pressed into the watch. The ring not only serves an aesthetic purpose but a functional one, too. It fills the space between the case and the dial for a complete, finished look, but the purpose of the ring is for water resistance. Domed crystals do not typically seal a case well, and this ring helps secure it tightly. Typically used for acrylic crystals, the tension ring compresses the plastic into a good seal. There are some diver’s watches that are the exception to all the rules surrounding tension rings, requiring cone-shaped dies for crystal insertion.
Mechanical/Compressed Fit
In terms of water resistance, a mechanical or compressed fit results in the weakest seal. It is also the fit that watchmakers have the hardest time with during installation. For this fit, the skirt of the crystal must be mechanically compressed to reduce the diameter before being inserted. When released, it creates the seal when the skirt’s upper coned shape forces the bottom down for secure contact with the case.
Choosing the Right Press Dies for Different Cases: Matching Tools to Crystal Shape
Choosing the right press dies is essential for securely installing watch crystals without causing damage. Different watch cases and crystal shapes require specific dies to ensure a proper fit and even pressure distribution.
Flat Crystals: Use flat dies that apply uniform pressure across the entire surface. This prevents distortion or stress fractures.
Domed Crystals: Opt for concave dies that match the curvature of the crystal. This ensures pressure is evenly applied without risking cracks along the edges.
Tension-Fit Crystals: These require stepped or slightly tapered dies that accommodate the tension ring, pressing the crystal evenly into place.
Sapphire Crystals: Because sapphire is brittle, always use nylon or rubber-coated dies to prevent chipping. Avoid metal dies, as they can create pressure points that lead to cracks.
Acrylic Crystals: Flexible and resilient, acrylic can be pressed in with slightly domed or flat dies but be careful of excessive force that could cause warping.
Snap-On Crystals: While rarely encountered in modern watchmaking, snap-on crystals are still in existence. For these, use the correct-sized dies that grip the outer edge of the crystal rather than pressing on the center, ensuring a secure fit without cracking. An alternative tool to use is a crystal lift, which may offer more precision.
Matching the right press dies to the crystal shape and material helps achieve a secure installation while minimising the risk of damage.
Safely Installing a Domed Crystal: Tips to Avoid Cracks or Misalignment
Installing a domed crystal requires precision and care to prevent cracks or misalignment. However, there are certain steps you can take to protect the crystal from damage.
Choose the right crystal size – Ensure the domed crystal matches the exact diameter and thickness needed for the watch case to avoid excessive force during installation.
Use a watch press – A press with the correct dies helps apply even pressure without stressing the edges, reducing the risk of cracking. Avoid using makeshift tools that can cause uneven force. Make sure to select the right-sized die for the crystal you are using.
Check for a good fit – Before pressing, test the crystal in place to confirm it aligns correctly with the case. Some domed crystals require a tension ring or gasket for a secure fit.
Apply even pressure – Press the crystal gently and evenly, ensuring pressure is distributed across the entire surface. Misalignment or excess force at one point can lead to cracks or warping. A screw-down watch press is the most exact when it comes to using controlled pressure for crystal installation.
Warm the crystal slightly – Some acrylic domed crystals can become more pliable when slightly warmed, making installation easier. Avoid overheating, as this can deform the crystal.
Inspect for alignment – After installation, check that the crystal sits flush and is centered properly. A misaligned crystal can affect water resistance and aesthetics. If you have a pressure tester available, you can pressure test the timepiece to ensure optimal water resistance.
The Ultimate Guide to Watch Presses and Crystal Installation Conclusion
A quality watch press is an essential tool for installing crystals with precision and ensuring a secure, professional fit. Whether working with acrylic, mineral, or sapphire crystals, selecting the right press, dies, and technique minimizes the risk of cracks, misalignment, or damage to both the watch crystal and the case. Proper handling, alignment, and pressure application are key to achieving a flawless installation. By understanding the different types of presses, choosing the right tools for each job, and developing your technique, watchmakers can install crystals with confidence. Investing in the right equipment and mastering crystal installation will guarantee long-lasting, professional results.
The Ultimate Guide to Watch Presses and Crystal Installation FAQ
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