There are 4 main styles of watch case back that you should be aware of as follows:
The Snap Off Case Back and the Notched Screw Case Back are the most common I’ve come across so far.
Snap Off Case Back
Mostly used in older vintage watches but also a few modern watches, this is simply a case back that is snapped on or off in one motion.
To open a snap off case back you simply wedge a knife (preferably pen-knife) or case opener up against the edge of the case back and flip the tool upwards to force the case back to un-snap itself and become free of the watch case. Some case backs have a small lip/notch (as To open a snap off case back you simply wedge a knife (preferably pen-knife) or case opener up against the edge of the case back. Flip the tool upwards to force the case back to un-snap itself and become free of the watch case. Some case backs have a small lip/notch as can be seen in the photo above, bottom right hand corner of the case back. In this case this is where you should insert your pen-knife/case opener to make this process easier.
There is a small risk of damaging or scratching the case with this method so proceed with caution and be careful not to cut yourself in the process.
There are a few key tools to aid in this process:
A standard pen knife is a great tool for this purpose and is what I was taught to use, but it is a personal choice. A pen knife also has the dual benefit of also being used to sharpen your pegwood (which we will come to in future posts). I was taught to go for a carbon steel blade as this is gentler and slightly more forgiving on the case metal to minimise the risk of scratches.
Best budget option is this Opinel No 6 Carbon Steel Folding Knife for around $15:
Best mid-range option is this Kpieit Folding Knife 5CR15MOV for around $30:
Best luxury option is this CRKT SIWI Fixed Blade Knife for around $80:
Go for the ‘Save’ option – Opinel No 6 Carbon Steel Folding Knife.
Case Back Opener Tool/Knife
The more standard case back opener tool comes in these two guises. I have begun to use these myself on more expensive watches in order to minimise the potential of scratches. I find that the different shapes of the blades gives me more flexibility to pick the correct tool for the case in hand.
Best budget option is this 2 piece set of Kocome Watch Back Cover Case Openers for around $4:
Best mid-range option is this 6 piece set of Anezus Watch Back Remover Tools for around $10:
Best luxury option is this Bergeon 4932 Back Case Opener Knife for around $40:
Go for the ‘Save’ option – Anezus Watch Back Remover Tools to give you a full set of all shapes.
There are other tools available, a few being much more industrial but I’ve not needed them so far.
Snapping the case back back on once you’re done is a fairly easy process and doesn’t require any tools. You just need to line up the case back, making sure if there is a notch in the case back (most likely for the stem) that this is lined up correctly. Then apply force with your thumb and fingers between the case back and front. A squeeze will generally suffice and you should hear the re-assuring sound of the click as it snaps back on. Inspect the case back edge all around to make sure it is on evenly to the case.
Notched Screw Case Back
This is definitely the most common case back type I have come across and also the easiest to remove and reattach in my experience.
The big give away in these types of case back is the notches around the edge of the case back, normally 6 around the circumference. Be wary, I have come across many vintage watches with a notched case back that are actually snap off case backs in disguise. Would love to understand the rationale behind this but doubt I ever will.
If you find a watch with what looks like a notched screw case back that is stubborn as hell and won’t budge with the tools suggested below. Then I suggest you try one of the snap off case back tools instead, just on the off chance.
There are a few tools available to assist for this purpose, I’m going to cover the two most common.
2/3 Prong Screw Case Back Opener
These Screw Case Back Openers are designed to have adjustable and interchangeable prongs so you can adjust the prong shape (size and thickness) to match the case back. You can also adjust the width between the prongs so they fit snugly into the notches on the case back. These adjustments then give you the necessary grip you need to turn and tool which will unscrew the case back.
There are also 3 prong variations of these tools called the Jaxa type. These are more stable and reduce the risk of the prongs slipping out of the notches and scratching the case back.
Best budget option is this Jorest Watch Wrench Back Remover for around $7:
Best mid-range option is this Otoolworld Watch Screw Case Back Opener for around $16:
Best luxury option is this Bergeon 2819-08 Jaxa Case Opener for around $376:
Go for the Bergeon 2819-08 Jaxa Case Opener to minimise any risk of damage to your case back if you’re intending to work on more expensive modern watches.
Sticky Friction Ball
Originally I bought the blue sticky friction ball (left photo above) very cheaply via eBay. On arrival I realised it came deflated and without the valve adaptor to allow me to easily inflate it. This and the lack of a pump made me decide to go for a branded option and pay more for a Bergeon Sticky Friction Ball. Bergeon are the biggest Swiss manufacturer of quality watch tools but equally one of the most expensive.
This is one of the simplest and most useful tools you will buy, you simply put your watch face down on a watch cushion, case holder or hold it in the palm of your hand and then push the ball onto the case back and turn. The friction of the rubber grips the case back and unscrews it, and the best thing is there is no risk of scratching the watch case.
To close a notched screw case back, you first manually screw the case back on, making sure it’s not crooked or slanted against the case. Then use the above tool of choice tighten it as much as possible. The sticky friction ball also works well for this process although i wouldn’t trust the tightness for a diving watch.
Best budget option is this MMOBIEL Watch Case Opener Ball for around $7:
Best luxury option is this Bergeon 8008 Sticky Friction Ball for around $20:
Go for the Bergeon 8008 Sticky Friction Ball that will arrive inflated and ready to use.
Screw Off Case Back
The screw off case back is identified by a series of edges, grooves, or threads (like the edge of a coin) around the outside edge.
I’ve not come across any of these types of case back as yet, but they are quite common on Rolex and Tudor watches. I have a lot more to learn before I’d consider taking one of them apart!
Rolex Style Case Opener
Normally you would use a special tool to remove these. These tools come with multiple size bezels so you will use the right size bezel for the case back, snap on the handle and twist to unscrew the case back.
Best budget option is this Watch Case Back Opener for Rolex Watches for around $31:
Best luxury option is this Bergeon 5537 Rolex Oyster Case Opener for around $185.
Again I’d recommend you use a watch cushion or case holder for this to minimise any risk of damage to the watch case.
If you plan on working with Rolex’s then go for the Bergeon 5537 Rolex Oyster Case Opener.
Case Back with Screws
The final type of case back is one with screws which is quite common for digital watches especially Casio watches. These are sometimes also used in some modern mechanical watches. I’ve only ever seen these on Hamilton mechanical watches so far.
These are easily removed with a set of precision screwdrivers. Make sure you to use the correct size screwdriver, rule of thumb is that the width of the screwdriver tip should match the width of the screw head. This will mean you have good contact and reduce the risk of a stripped screw which you will struggle to remove.
Always purchase screwdrivers with replaceable blades for longevity.
One thing to be aware of here is that although all watch movement parts only use flat headed screws, there may be some case backs that will use Phillips headed screws. So you may need both types of screwdriver sets.
Best budget option is this Chumia 8 Piece Precision Screwdriver Set for around $14:
Best mid-range option is this set of 9 Horotec MSA01.218A Watchmakers Screwdriver Set for around $160.
Best luxury option is this set of 10 Bergeon 55-614 6899-A10 Ergonomic Screwdriver Set for around $281:
It’s worth splashing the cash for a branded set of precision screwdrivers from Bergeon or Horotec as this is a key tool you will use constantly. I use the ‘Spend’ option Horotec MSA01.218-A screwdriver set mentioned above, and I’ve been very happy with them.
That’s all I have to say about case back removers for now, I will most definitely add and edit this post as I learn more. Hopefully i will be able to source photos of the missing case back types and tools.
If you think I’ve missed anything or have anything to add, please comment below.