Help mounting new grinder

[SkagSig40]

cross posted in the makers forum but thought I'd post here too. Ok I'm at my wits end and need some help! I'm getting into knife making and I bought a Northridge grinder which is about 80-100lbs?. I built a steel pedestal thinking it would be perfect for mounting my grinder to. The darn thing rocks back an forth bad which is unacceptable as the grinder needs to be solid and can't move or it will mess up my grind lines. The bottom plate is 3/16" but it warped. I got that issue fixed but now the center tube flexes under the weight of the grinder and sways when I push into the grinder. I spent 2 full days(working through lots of issues) and $160 on the project and I have to scrap it as it is just not ridged enough to support the grinder properly. I'm already WAY over my budget and cant afford to buy all new steel.
I think I'll have to build a wood table to mount it to. It needs to be SOLID and put the grinder platform so my arms are 90 degrees out like in the picture. I also need it to be portable so how could I mount wheels to is so I can move it around but still be solid and not move at all when using it? It seems like such an easy job but it is kicking my ass and I'm at my wits end with the darn thing! Any ideas would be extremely helpful! Also how does the height where my arms are going to be grinding look? Am I to high or to low? Thanks!

Here is what I ended up with and still stuck back at zero:

 

[Wowbagger]

Structural mild steel is very inexpensive you may be buying at the wrong place. Seek out a real steel yard or perhaps a scrap yard. That said . . .

Set up a way to anchor the stand you made to the wall when you are using it. That will dampen any flexing. Just a horizontal piece of 2 x 4 and a C-clamp could do it if you can find or rig a place to clamp to.
To the plate with the wheels on it you could add a couple layers if thick plywood or better yet a couple inches of solid wood. Perhaps from an old pallet; some places throw those out after a shipment is received. I think a lot of your flexing is in that thin plate on the base. I am not saying put the bottom plate on a pallet. Just use the wood slats from the pallet; use two layers and threw bolt it to the base. Some heavy duty construction adhesive between these layers would be extra insurance against movement between the chunks of wood.

THEN

To this thick ridged base add washing machine feet. They are threaded posts with rubber feet on the bottom. You thread them down to level / stabilize the base and thread them up to allow the weight to come onto the wheels to move it. Pretty quick to do with a screw gun / drill with a socket adapter.

Failing anchoring this to the wall you could run all thread from the four corners of the base up to the four corners of the machine mounting plate. Using nuts on the all thread just put a little tension on the all thread rods (think spokes in a motorcycle wheel). Not as good as the above though.

 

[Wowbagger]

Yes that is going to mess with the height. You can take out a section from your pedestal.

Or

You could, and I have done this a fair amount, put concrete anchors in your floor and bolt through your base into the floor. Put the anchors near the tips of the triangular braces. Beside them but toward the points.

Again with the drill with a socket adapter it is quick work to run the bolts out of the anchors so you can move the machine to put the car in the garage. Your pedestal is still going to flex some. That is where the horizontal 2 x 4 over to the wall is your friend.

Next time go AT LEAST 3/8 inch for the plate bellow the machine and 1/2 inch for the base.

PS: old steam pipe like six inch is better for the pillar.