It has been said, with a big enough hammer, or enough dynamite, any problem can be solved.

Thank you. I was worried 'hit it with a hammer' may not be socially acceptable as an X2 fix, but I also thought it was important to get the word out that sometimes that does indeed work well. Secret is just firm taps from a big enough hammer. If I had not filled the core with an epoxy/steel/sand mix I would have been more reluctant, fearing denting or buckling or cracking of the column, but it all came out pretty solid, so I didn't think that would hurt it any more than beating on an old Buick flathead engine would hurt that. I was right.
For those wondering, since hardly anyone just sells pre-cut 3/8 inch HSS fly cutter bits and all of my efforts to grind one of my own have failed, I used a store (Micro Mark) #4980L 8mm lathe bit. Left hand bit tightened down upside down into the fly cutter. It was loose of course. So I tightened a single edge razor blade edge down into a workbench vise, then snapped the back off with a big hammer. Snapped clean. I took that piece of steel back and it fit perfectly alongside the lathe bit in the fly cutter.

Hmm, it probably isn't the approved fly cutter shape, but I can report (as the photos show) the cheap 4980L mini lathe bits work perfectly in the Micromark fly cutter on hot rolled steel. I may buy some more of them.
I have a tachometer for the mini lathe. Hooked it up to the SX2, took readings, and then marked them on the rheostat box. No need for a tach now 'cause that effectively gave me a speedometer.
I know, I was supposed to run it at about 430 RPM and 8 feet minute feed. That worked, but in the real world so too did 6-800 RPM and about 5 feet a minute hand cranked. Just slow and steady.
So will an SX2 with an epoxied column cut steel plate? Oh heck yes.
Biggest problem I am encountering with the SX2 now is the small size of the work aperture. That steel plate is about 6" by 2.75" and in order to fly cut it I had to take the big Sharf vise out of center position, insert the fly cutter (only 7" of Z room), then put the vise back. Of course that business with moving the vise first wouldn't be needed on a full size machine. Likewise I needed 3" on either end of the 6" steel plate for the fly cutter to fully exit the workpiece. Unfortunately my SX2's bed travel is only 11" along the X axis. One end suffered and did not experience the full fly cutter effect. Likewise, although I was kicking around the idea of flycutting the piece along the Y axis to check that tram, since the bed travel is only 4 inches and I should have 3 inches on either side for the fly cutter to exit, I realize now that test can not be run on this machine as I will not have even one side clear enough for the flycutter to exit along the Y axis. Even doing it sideways and with only one side fully exiting, I would need at least 6" of Y travel (probably more if you take the vise footprint into account). Durn shame. T'would have been a good easy test of Y axis Tram.
I have a faint suspicion that my mill head leans inward just a hair. If you look at the plate you see the flycutting looks fainter along one long axis. That was the side near the column. I have read many webpages where folks found Y axis issues with their X2 heads. Aluminum foil fixes and all that. I had the head off yesterday morning while I was playing with the quill gear (shaft was very grungy and the fine adjustment had been sticking and no, it isn't necessary to remove the column to detach the head or remove the quill handle/gear) so I see where the shim would go, but sheesh, couldn't they have done that at the factory? If they didn't want to put it together right (or polish out the tool marks on the gibs) why didn't they just drop the price a little and send us a box of loose parts as a kit (as Jinma did for my 8" wood chipper a few years ago, a 5' 3/4 ton crate of metal parts with instructions for assembly written in Chinese)? Yeah okay, maybe a head shim is in my future too. Don't know yet. For 99% of anything I anticipate doing here the fact that the mill head is possibly the thickness of a cat fur off in angle at the bed really won't matter worth a durn. Trust me, the lawn mower won't care.

But anyway, the X2 work aperture is small, but I have no room (or funding, or electricity for a real machine (LoL let's crush the basement floor with a real machine, NOT). Still for well less than a $1G it is a durn nice accessory for any work at home mechanic type. There is just so much to learn with it.