Making a Stainless Steel Watch Case and Back on the Shapeoko 3 (Start to Finish)

Awesome project Rich, I will be “watching” closely, haha!!

On the subject of watches I have a question or two, but I’ll send via PM to not hijack this thread.


Short answer: 1/8 cutter: 10,000, 1/16 cutter (up to) 15, 1/32 cutter Up to 30,000 on the Makita RT700

Longer answer:
The SFM recommendation for Austenitic Stainless Steel (high end) is 350, and using an1/8" cutter at 10k rpm yields 327 SFM, so I am just inside of the cutting recommendation. I have some leeway on the 1/16 and 1/32 cutters, so I will be using them around 250 SFM

Remember this is 303 Stainless Steel (designed just for its machining properties. I wouldn’t call it free machining like leaded brass, but the difference between 303 and 304 stainless steel is night and day)


That is very good information to know. Thanks

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I actually never knew the distinction in the types of SS, so that is very good to know, thanks!

I look forward to watching this thread.

Is there a reason you’re using the Shapeoko 3 and not the Nomad? I thought you have a Nomad, too?

Nope, I only have a S3

For me, it’s all about the cutting power:

Nomad = 50-watt spindle (1/16 hp)

Shapeoko = 900 (1.25 hp) watt spindle

Need I say more?

I would LOVE a Nomad…as soon as they offer a higher wattage spindle…(Carbide3D, are you listening???) LOL


There’ve been a couple of folks who have installed more powerful spindles, but haven’t had marked improvements in performance (or if there were, they haven’t shared that or I missed it or misunderstood). ( Nomad spindle motor....upgrade?
and Nomad 500 Watt Spindle Upgrade for the curious).

One thing which I’ve been wondering is if a different pulley arrangement might be advantageous — but I really suspect that having a more powerful spindle would then result in the need for a more rigid structure, and before you know it, you’d end up with a machine which would need to be delivered on a pallet, and would require multiple pieces and assembly onto a special-purpose table — ref. “The Wonderful One-Hoss Shay” and all that.


I still haven’t gotten past the EMI issues on my Nomad spindle upgrade. I’ll probably have to go with a brushless motor to get it to work with the C3D control board. Even with shielding a brushed motor knocks out communication instantly.


Fun project, Rich! Looking forward to your follow-ups.

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Just looking at the design of the nomad vs SO3 I would think the Nomad is considerably more rigid than the SO3. I might be wrong but I would think the Nomad could handle a spindle several times more powerful than the one currently installed. I am hoping The C3D team is considering that as a future road map item for the Nomad.

-regards, Ed

Setting up (using the Touch Probe to establish my X0, Y0 and Z0.
Machining the two critical back bores.

I was VERY imresses at the surface finish (The large burr at the bottom is the remainder of the “onion skin” that I leave as to not dig into my waste plate)

Next, it is the O-Ring groove. 1/32" flat 2-flute coated end mill

Now it’s time for the eight 0.8mm (0.0315") tap drill holes that are 4mm deep PS I am NOT looking forward to tapping these holes (Wish me luck):

Last thing to do on this side is to rough and finish cut the case outer surface (Keeping the tool cool by providing a local flooded environment:


Superb, what is next?

Total machining time you have into it at this point?

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To the best of my memory: about 7 ish hours ((Most of the machining is done with a 2-flute 1/8 TiAlN coated end mill, just one and it’s still in great shape))

ID bores: 3 hrs,
O-Ring: 20 min,
Drilling 15 min
Rough OD (back) 2.5 Hrs
Finish OD (back) 1 hr

What’s next, the Front. Next project? No clue

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I wouldn’t be able to resist trying to tap those holes before starting the front. Curious to hear how that goes.

Also, how does that flood coolant work? Did you screw through the bottom of the container or is that somehow added around the watch?

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The Flood Coolant works awesome! The end mill will throw a small amount out of the container, but it’s minimal. I drilled two 0.250 dia holes to suit my metal table (50 mm spacing) and just bolted the thing together. Not a drop leaks out of it via the bottom.

I completely understand, but I plan on using my Hand Taper but I need to make a very small bushing and will do this while the front is being machined.


So amazing, I cannot wait to see this.

Will there be any need to polish the case when you’re done with machining?

This entire thread has got me to thinking how watches are mass-produced and also how high-end watches are made. I realize they’d be starting with molded parts but you’d think even a Timex would require machining, so how did they do that and still sell a watch for $20?

Keep it coming.

As you may (or may not) know, I spent some time in Switzerland’s watch making region of Basel (it’s not Geneva).

High-end watch companies machine their cases and backs out of billet material (just like I am doing), whereas; low end (commodity) watch companies start from a brass nearly complete blank and then plate them in a shiny finish.

I also spent time in the Gun making industry (US East Coast) and here is where I learned a lot about the different textures (or finishes) that are applied to a firearm. So I am thinking that I want a satin finish on the Watch top face. This will mean sanding, sanding, sanding followed by a Glass Bead sand blast.


How long does it take them to mill a high end watch case for a premier watch brand? Just for comparison.

Also, just for comparison, how long do you think it would take to mill one out of wood and/or plastic on an S03?

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I would estimate: Wood = 1/10 the time

About an hour on a high end 4-axis mill.