So I have a couple of different bench grinders and I'm hoping to get some more and I had an idea on how to make all of them useable while saving on workbench space

I figured someone here has probably had this idea before and either has some tips on how to make it better or comments on why it doesn't work

 

The idea is to have a thick steel top on the working bench, something around 25mm plate (hey, I'd rather have too much rather than too little) and drill a hole in it and then file or broach it square

mount all my grinders and other similar tools, maybe even vices too, on another plate just big enough for the footprint, countersinking the bolts so that the mounting plate is flush on the bottom.

then weld a U shaped piece of flat bar that fits in the hole on the table to the bottom of those plates and use a wedge to secure them to the table, then changing out grinders or vices should be as simple as tapping out the wedge, lifting it out, dropping the new one in and whacking the wedge back in place

now that I have typed this out, would the wedge even be necessary if I would just weld a square bar matching the hole on the table?

It's a sound idea. Start out just dropping them in place, if one moves too much you can drill and wedge it or pin it. 

When I was working on the drill crew one of the types of auger coupled with hex, box and pin joints with a clip pin to lock it. We had quite a bit of solid flight auger that got torn up, bent, worn out, etc. so I had plenty of joints laying around. I welded a box flush with the welding table top and made mounting plates for a few tools with a pin and used them exactly as you describe. Mounted similar on the bumper of the electrician's truck and they stopped having vises stolen. Then they asked me to make them a rail anvil so I put a hex pin on it too. 

I can say from personal experience it works a treat. I recommend you put the box as close to a corner as possible so one side of the vise jaw clears the side of the table. This will allow you to bend stock all the way around without hitting the table. Make sense? If you can you can use one of the table legs for one side of the box making it even stronger.

Frosty The Lucky.

 

I made something similar to mount a machinist's anvil in my striking anvil/portable hole. I haven't been particularly happy with it, but you're giving me ideas on how I can redo it better.