The Dimmer speed controller module reshapes the mains AC waveform to control the power delivered to the load, effectively controlling the device's speed or brightness. See manufacturers specifications for limitations.

The dimmer module is rated at 2KW, hence can easily handle the power tools that I wish to speed control. The tools I have targeted are a Makita 700W portable bandsaw and a Makita 940W belt sander. I will be making two controller units. Both these tools are workbench mounted, so in a fixed location. In addition to the speed control, this controller incorporates an easy to use and convenient power switch assembly.

To help me create this box design, I have also created a 3D drawing of the dimmer module and shared it on Grabcad.com. See:
https://grabcad.com/library/2000w-dimmer-speed-control-module-1

The controller box incorporates an industrial style on/off switch. I cut excess panelling away from the switch part to fit it into my box design. The switch is supplemented by a lever switch panel that makes turning the switch off SO easy.

The dimmer speed control is varied by a case mounted potentiometer. Attached to the potentiometer is a custom 3D printed rotary knob. The knob provides analog control over the dimmer speed power. Rotating the knob clockwise increases the power to the connected device, hence increasing it's speed. Rotating the knob counter-clockwise does the reverse and reduces the power to the device.

The dimmer module is readily available for purchase. I purchased my module from Banggood for about AU$5 (in a batch of 3) from here:
https://au.banggood.com/3pcs-2000W-Thyristor-Governor-Motor-220V-Regulating-Dimming-Thermostat-Module-External-Potentiometer-Voltage-Adjustable-p-1604852.html?imageAb=1&cur_warehouse=CN&DCC=AU¤cy=AUD&akmClientCountry=AU

The industrial switch I used (A$13):
https://www.ebay.com.au/itm/144346556314

The mains power socket I used (A$8):
https://www.jaycar.com.au/mains-panel-socket/p/PS4094?pos=12&queryId=3f318274a2de7ff4b7be2e23c4a815cf&sort=relevance

Here is my 3D printed solution case. The case lid is held in-place by four 3.5x15mm screws from underneath. PCB and switch are secured to the case using miscellaneous 6G, 7G and 8G self-tapping screws.

The case and printed parts have different colours of my choosing. Of course, you can select your preferred colours, too. I've taken advantage of my multi-colour printer, but also provided options to get some mixed colours via manual filament swap.

To make the print result more interesting, I printed the STOP lever part with two different filament colours. I do a filament colour swap part way through the print to make the text white, again after 3 layers back to red. The filament colour swap is setup in your slicer software. Setting up the filament colour is easy in Bambu Studio; other slicers probably, too.

My print is made in eSUN PLA+ 1.75mm white, black and red filaments, with 0.2mm layer height and 15% infill on a Bambu X1 Carbon printer.

I hope that you can find this print useful, too.

Remember to leave me some feedback or even a tip to keep me enthused to make more of these drawings.