I have a small 6 x 12 Boyar Schultz surface grinder (maybe 700 pounds) that is usually in the way, but occasionally comes in handy. I'm thinking about welding up a mobile base like the one below. Would it cause extra vibration? My concrete floor is flat and smooth and the grinder would be no more than an inch off the ground so I don't think there is much risk of it tipping over. Is there any reason why I shouldn't put it on a mobile base?
I suspect that you will find this particular product to be troublesome. Your concept however is sound, but what I would consider is to affix your grinder to a stout base that can be fitted with casters on a temporary basis. A friend of mind has adopted this in his crowded shop. He welded on square sockets that he can slip casters into when he needs to jockey things around, and this is accomplished by a simple cam that lifts the machine (or acorn table or welding table) about 1 inch so the casters can be inserted or removed. This also has the advantage that the nice heavy duty rubber tired ball bearing casters can serve to move anything he needs to move single handed and has only the expense of one set of wheels. The wheels usually reside on his welder as that is the most moved machine and his base has provisions to hold his bottles of gas and stow all if the hoses cables, and wires etc.
The sockets can also be used to hold feet that can be leveled independently.
I have "mobilized" almost all of my equipment due to space constraints, using quick-change lean philosophy. I have made bases that include a 4 swivel caster base for a Walker-turner cast iron drill press that I had to disassemble to move and install due to its weight. My approach for these bases is to weld a simple box frame that the equipment sits in / on with casters mounted outboard of the frame on angle iron mounts welded to the frame. The key is how to level / stabilize. I solve this dilemma by drilling a clearance hole for a
3/4-10 cap screw and welding a 3/4-10 nut next to the swivel with adequate clearance for the swivel radius. Once fab is complete on the mobile base, set the equipment into the frame and it will roll around to where you need it. When you get it where you want it, run the 3/4 bolts down until they lift the equipment slightly off of the casters. Level to your heart's content. The base is as wide as or wider than the original, so it's stable. Sometimes I place steel cups or rubber pads to dampen vibration or protect the floor. It's really handy to be able to use my speed wrench from my socket set and quickly raise the leveling screws, roll / spin the equipment to where I want it. I've made over twenty of these for myself and friends over the last 15 years, so the idea is tried / true.
Roger's idea is probably the best thing you can do in your situation. Running the machine while it's on casters will create unnecessary vibration while you work. Typically a surface grinder is used for very tight tolerance sizing, and for surface finish requirements. Neither of these operations will be aided by an unsturdy machine base.