I'm in need of some hardware equipment (saw, grinder etc). It's a one time thing so I don't want to buy those. Are there any shared workshops equipped with basic tools that let people use them for hourly charges? It'd be cool if there's any such thing exists.
Every Lowes, HomeDepot, Ace Hardware etc rents tools. Even my local library does this. When you type Tool Rental into the Google (map) Machine for Seattle it lights up like a Christmas tree. It looks like you never tried that first... Note: The makerspaces here don’t rent out tools to take with you. But you can use it onsite.
Metrix create space is one on Capitol Hill.
Not from Seattle but we have one in Austin, what you are looking for is called a hackerspace or makerspace