Simon was not afraid of the sound of tools. He could follow me when working with the saw, staying close, and even when using the angle grinder on stones. It should really be too much for his hearings, but yet he did stay, so I had to limit my usage of the angle grinder to occasions when Simon was not close by.
However, even though he would be with me when using an angle grinder, or a table saw or other mean machines making a lot of sound, there was power things he was very cautions of. A thing looking like a vacuum cleaner immediately caught his attention. If it also sounded like one, he was on full guard. It was possible to vacuum around his chair, but with a cat very much on full alert. Normally he would leave.
In a similar way, a lawn mover was something he was cautions of as well. He would not be much afraid of it, but he would avoid being cornered so it could come onto him.