My 1.5kW water cooled SO3 XL

There have been some discussion around water cooled spindles in New spindle, water cooled, so I thought I would finally post some details of my setup.

There’s a lot of other stuff going on to control relays for spindle e-stop and safety switch, auxiliary relays to control vacuum, and various other power supplies. Everything is driven by an RPI and touchscreen monitor using bCNC. Let me know if you want any other specifics!


That control equipment “electrical stuff” picture is amazing, what a project, appearantly all works fine, congratulations. Anything can work if you do…Jude


AWESOME setup.How do you like it so far. Im looking to start out using this.

But i will control the speed through the VFD. How was it mounting the new spindle mount to the Z axix? any mods needed to be done?

Chris from Blue Ox was able to customize the mounting hole location on the spindle bracket. I then used 6mm M5 spacers to move the plate off of the z-axis plate. Specifically, I ordered Given the tolerances, I ordered 15 and took the most tightly matched for my mount. I also ordered 25mm M5 bolts and nylon insert flange nuts to finish the mounting. Below is a picture of the setup.


Could you tell me how big of a water reservoir does one need for a spindle?
Thanks for all the detailed info!


I can’t say I sized up the cooling capabilities for the setup I used. As far as I can tell, no useful specs are published about these spindles wrt the required cooling. I chose the Swiftech solely because it was all in one, a closed system, and I figured that it if it could cool a CPU, it would work fine for a spindle. That said, I haven’t noticed any excessive temps in the spindle, even after 30-40 min jobs.

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I wanted to share some of the aluminum work I’ve done with this setup. 1/4" 6061 pieces I’m working on for DIY speakers: