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Pocket Watches: Measuring and Replacing Crystals

Sometimes, the unevitable happens and something goes wrong with your most beloved watch and you need to take it for watch repair. However, you can try to do your own watch repair when it comes to replacing a pocket watch crystals. This page intends to explain to you how to achieve an installation of a new watch crystal from start to beginning. Good Luck & Reach out if you need our assistance. 

Step 1. Determining the correct type and height of your pocket watch crystals. 

There are two main types of cases for pocket watches: the hunter case or the open face.

1. The hunter case has a metal cover over the dial of the watch, and the glass used is very thin.
2. The open face watch has no cover, but instead the crystal is exposed, so a thick pocket watch crystal is used.

1b. Domed watch crystal or Flat glass

Pockets watch crystal are available from flat to highly domed and are numbered from 1 to 8. The higher the number, the higher the dome, so that a crystal with ‘1’ is the highest domed crystal and a crystal with ‘8’ is flat or almost flat (see diagram below)

1. Hunter case or thinner pocket watches use low-domed crystals, usually from 5 to 8. The crystal must be high enough to clear the hands, but low enough to fit under the cover. The crystal used for these watches is very thin and fragile so it should not be pressed in the middle when fitting, or even to close the door. Thicker hunter pocket watches generally use crystals 5 or 6.
2. Open Face pocket watches require crystals with a higher dome, usually from 1 - 4. The crystal must be high enough to clear the hands.

Step 2. How to Measure Watch Crystal Size

Lots of people ask us how to measure a watch crystal and antique pocket watch crystal replacement is no different. It is very simple, so relax, you can do it. If the crystal you’d like to replace is still in hand, the process is simple: Just measure the diameter of the crystal to obtain the proper size. A caliper is suggested for a more accurate reading, but you can also use a normal ruler. Measure in two to three different places to confirm the size.

2b. If the crystal is broken or missing, you will have to measure the inside of the bezel. Again, a caliper with inside measuring jaws will you give a more accurate reading, but you can use a normal ruler. The crystal sits on the stepped ledge on the inside of the bezel. Measure the inside of the bezel above this ledge in two to three different places. 

There is no pocket watch crystal size chart. Pocket watch crystal sizes come in increments of 0.1 mm and we suggest you always buy a crystal one step down. 

Step 3. How to replace pocket watch crystal

Cover the watch dial with a piece of paper for protection.

Apply UV glue along the crystal edge using the syringe needle tip.

UV glue is clear, easy to clean and allows you infinite amount of time to work with, so long as it is not exposed to UV light or sunlight while working with it.

Use cotton buds to remove any excess glue.

We recommend using GS Hypo Cement, also available from our online shop:   https://www.sdemanuele.com/shop/consumables/hypo-cement-tchypo

After you apply the glue, place the glass on the bezel and press down gently, but firmly around the diameter of the glass until it sits in place.

Extra care should be taken if you are fitting a thin glass on a Hunter pocket watch.

Pressing on the centre of the glass might crack or break the glass so make sure to only press around the diameter.

Once the glass is in place, put the watch under direct sunlight and wait for the UV glue to cure, which takes around 15 minutes.

Checklist for pocket watch crystal replacement 

1. Determine the type of pocket watch: hunter case or open face
2. Determine the height of glass
3. Measure the diameter of glass
4. Select the correct crystal from our site (don’t forget the UV glue if you don’t have any handy!)
5. Apply the UV glue to the crystal and fit it in place
6. Wait for the UV glue to set – 15 minutes in direct sunlight

S.Demanuele Pocket Watch Crystals

The pocket watch crystals we have in stock are the original antique crystals manufactured in the very early 1900’s. As such, the glass may sport imperfections and sizes may vary slightly.

We hope you found this article on how to change watch crystal useful!  If you have any doubts about the glass you need, send us an email on [email protected] or call us directly on (+356) 21 220 650 (Monday to Friday from 09.00 – 13.00).

Crystals are non-returnable.