I came up with this in the process of overhauling my workshop, and the last big change is going to be throwing out the improvised wooden table that held my belt sander, and replace it with a sturdy workbench that will hold at least 2 of those grinders, and possibly 3 sometime in the future.

anyway, aside from being sturdy, I wanted the thing to have no legs. The wall itself was not 100% flat, so that made it impossible to just buy wall hooks for supporting my workbench. They would not be level or equal. And most of the off-the-shelf stuff is not for for heavy loads anyway. So I bought a load of steel L beams, roughly 3/16" thick, 1.5" wide. First I mounted the vertical beams. Each of those is mounted to the wall with 3 bolts that are meant for hanging cast iron radiators from a wall (2 bolts will hold a 200 pound radiator easily). the position of the bolt is indicate by the red arrows. I placed 2 bolts at the top because that is where all the weight will pull.

Then I welded on the first horizontal support, using a level indicator to make it perfectly level. I repeated this for the other 2 supports, using the first as a reference. After that I welded on the diagonal square beams. I'll not call it a professional welding job. It is basically just a frame that I melted together using welding rods. After that I coated everything in hammerite to protect it from rust. Each of those frames is perfectly level with the others, and is strong enough to hold my full body weight at the full extent of the horizontal support without moving. Now it is ready for the wooden cross beams and the table top

In my shop the grinder would power up the wall to be a large noise generator to share it's complaints with the neighbors.  Keeping it isolated is the need for me.

It's not hard to take that same basic idea and make a nice folding bench for those with limited space constraints. A few bolts or pins instead of welds and you can collapse the bench either up or down to clear space.

Indeed. I thought about a collapsible design, but since this thing is holding my grinders, and they're not meant to be moved around, there was no point. Welding everything in place has the advantage of being rock sold and cutting down on the vibration. Btw, if your grinders are balanced properly, they shouldn't vibrate at all. Mine don't

It's not the grinders that vibrate it's cutting steel that makes the noise.

Frosty The Lucky.