CNC Your Own Watch Case | DIY Mechanical Watch - Part 1

One day, I was browsing the internet for inspiration for my next project when I remembered that my father-in-law had recently given me two old mechanical watches, maybe I could do something with them. As I explored the internet to gain some ideas, I discovered a vast community of DIY watch enthusiasts. Building a mechanical watch yourself and wearing it daily - that's very fascinating! I had to make this!

1x NH35A Mechanical Movement

1x Watch Hands

1x 18mm watch strap

Dial - found an old one (for testing) with the correct thickness needed for this build

Fusion 360

Access to CNC/3D Printer

As I dug deeper, I discovered that you can buy almost everything needed to assemble your watch, from the movement to the hands, all customizable to your preferences. Being from India, I found that while there are some watchmakers here, there's no well-known DIY watch community. Additionally, finding individual parts locally is nearly impossible. eBay turned out to be my best option for sourcing all the necessary components.

I decided to use an NH35 movement because it is the most commonly used and has readily available resources and support. I also purchased a couple of sets of watch hands to match the design I had in mind. However, for the case and dial, I decided to take the DIY route and create them myself.

PCBWay has been a great help with my PCB projects. I came up with the idea of creating a watch dial using a PCB - taking advantage of the various color options and layering techniques to achieve some cool effects. In addition to their PCB services, PCBWay also offers CNC machining, which I can utilize to CNC the watch case.

The plan is to divide the project into two parts. First, I'll design the watch case in Fusion 360 and have it CNC machined. In the next part, I'll design the dial using PCB and assemble the watch.

Let's get started!

With no prior experience in designing watch cases, I turned to the internet for inspiration. I found a few helpful videos from Shapr3D and Aviv Makes Robots that kickstarted the design process.

Additionally, I discovered the NH35A datasheet, which provided extensive information, including dimensions and assembly instructions for the movement. The dimensions were particularly useful for my design. Using the datasheet, I roughly modeled the movement, ensuring I included all the critical dimensions needed for the case design. This helped me understand how everything fits together.

I decided to use an 18mm standard-size strap for the watch.

The design is not going to be anywhere near waterproof.

A typical watch case consists of two pieces: the case body and the case back. I particularly enjoy having a transparent case back, allowing me to appreciate the inner workings.

I kept the overall design very simple, just the bare minimum, without too much experimentation.

I 3D printed several revisions in PLA to ensure the movement fits into the case. I used an old Ender 3 FDM printer, which doesn't provide a smooth finished print but was good enough for testing.

Finally, you need to create a technical drawing for manufacturing the case that needs to be uploaded along with the 3D file. Watch this video if you need help in creating one in Fusion 360.

If you're looking for a 3D-printed watch, you can stop here. Resin can give the best-looking results.

Once you are confident that everything fits perfectly and looks good, the next step is to bring it to life. If you have access to a CNC machine and the necessary skills, you can proceed with machining your design. However, if you're like me and don't have either, there's good news: PCBWay offers CNC machining services in addition to PCB services.

First, export the .STEP file from Fusion 360 and upload it to PCBWay. Here are the options I chose:

• Material: Aluminum
• Type of Aluminum: 5052
• Color: Silver White
• Upload technical drawing

You can leave the rest of the settings at their default values.

Aluminum is not the ideal material for a watch due to its softness, which makes it susceptible to dents and scratches. Instead, I would recommend Stainless Steel 316L. While it is a bit more challenging to work with and therefore slightly more expensive, it offers superior durability.

I found a dial from an old mechanical watch whose diameter and thickness perfectly matched NH35 movement. I also had an 18mm strap lying around that I could use to test the lugs. I am using those just for testing purposes - they would be swapped out in the final build.

This was my first experience using a CNC machining service, and the results exceeded my expectations. The finish is excellent even without any special requests. Additionally, the ordering process was very straightforward.

While working on this project, I discovered another Instructable member, Johan Link, who has created a masterpiece and well-documented the process. I wish I could have found this project a bit earlier. Pretty sure there are a lot of updates I could think of to my design after going through his.

Anyway, in the next part:

• Design a dial using PCB and get it fabricated
• Add glass to the body and case back
• Get an appropriate-looking watch strap

I hope you all enjoyed this project. Give a like if you did and subscribe for more such projects. See you in the next one!