Bamboo soap dish

One of the first things I ever tried to mill was this ‘Grunblau soap dish’ design I found by accident on the interwebs. It turned out that the project had too steep of a learning curve for me at that time. The fact of the matter is I was just getting to know my machine and had yet to understand all its quirks. Also, there were some issues which I won’t elaborate on, but suffice to say that I think the Arduino/Gshield setup wasn’t calibrated properly, which caused me a lot of headache.

Yesterday, I made a new attempt, of which you’ll see the result here. But first things first:

Youtube video of the original designer HERE. His website HERE. All credit of the design goes out to him.

The design is available for purchase on his website, should you be interested. Obviously, I can’t make the source files available for download as I usually do.

I won’t go too much into detail about the process itself, because the video in the link above explains everything really well. But one thing I do want to elaborate on is why I like this project. First of all it looked like a beautiful design. From a technical point of view, there’s also quite a lot to keep track of (hence the steep learning curve). There’s multiple tool changes on the 2 sides, the flipping jig is really really clever and the organic shape is ideal for testing machine settings, such as stepover and general feeds/speeds. Because the dish is only a few millimeters in thickness, the process is quite unforgiving.

If you purchase the files, there’s a readme included with most of his cutting parameters and used endmills. If you’re confident your machine can handle his speeds/DOC’s, there’s even ready-to-go gcode included for all machining operations. But the objective for me was learning to make a relatively complex part from start to finish, so I made my own toolpaths. Moreover, I work in metric, and don’t own the specific endmills the designer used. I also had to re-work the flip jig to match my endmill diameter.

Roughing side 1:


Finishing side 1:

tray03 tray04

Cleanup of the holes side 1:


I don’t have pictures of the ‘side 2’ operations, but it’s basically the same thing. I do have a video though that’s kind of an overview of all the machining operations, and shows the awesome flip jig in action.

I used different stepover values for different sides: 5% and 10%.

tray07 tray06


tray08 tray09

And off course, with soap 🙂

tray10 tray01

Now, did everything go as planned? Hell no! I actually started with a piece of scrap bamboo that was just smaller than what I had anticipated in the software. And that was the first of several concessions I made. Now, let me give you one piece of advice: NEVER make concessions when it comes to a CNC project. It will always bite you in the ass sooner or later. Therefor, always prepare 100% and always make sure everything is exactly as planned in the designing and toolpathing stages. But I am a stubborn SOB, so I proceeded, hoping it would all work out in the end. And it kind of did … i guess … 🙂

Stock material was slightly undersized (because I used a piece of scrap, bamboo is expensive you know…). This caused my working zero to fall outside the stock box (which is a pain for zeroing after a toolchange). Stock material was also 0.5mm slimmer than it was supposed to be, and had some glue gaps that I didn’t like (can be seen in ‘side 2’ close-ups). Also, I underestimated the total cutting time, so I had to do it in 2 times. I powered off my motors in between, so my flipside zero wasn’t spot-on anymore.

But all things considered, I think i’d call it a success!


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