Motor Speed Controler for Power Tools

speed controler box for all motor AC. i really need this coz i can modification drill and angle grinder for cutting or sanders. Easy for build and very cheap but very usefull
hope this video can give inspired
https://youtu.be/DA_wooqDv7U

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<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="https://www.homemadetools.net/homemade-motor-speed-controller-2"> <img src="/uploads/248537/homemade-motor-speed-controller-2.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="https://www.homemadetools.net/homemade-motor-speed-controller-2">Motor Speed Controller</a> <span> by <a href="https://www.homemadetools.net/builder/Didpoolhall">Didpoolhall</a></span> </div> <div class="tags">tags: <a href='https://www.homemadetools.net/tag/motor'>motor</a>, <a href='https://www.homemadetools.net/tag/controller'>controller</a> </div> </div> </div> </div>
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I am terrible with electrical and this could solve a problem for me, but I hope someone can help me sort this out.

I have a 2x72" belt grinder, and it runs on a 1HP motor, with no VFD.

Would this project be more like running the grinder on a dimmer switch, which I have been warned not to do, or like running it with a variable frequency drive?

Many thanks,

G.

It looks to me like you would just be reducing the voltage to the tool. If you do that with the tool under load that would be a good way to burn out the motor.