Finding a way of making my lathe unconditionally steady, constantly aligned and positively unwarped on any table just about anywhere, I stumbled upon HMT member "Xynudu", Rob's page:
My home made metal lathe bench
There he cleverly adapts the method used in the workshops of naval ships :
The Spanning Beam or (more appropriately) Torsional Beam Lathe stand,
whereby the lathe is bolted atop a rectangular box girder (wider and longer than the lathe's footprint) to avoid all bending and twist,
adding two rigidly fixed legs at the headstock, and at least 1 leg at the tailstock end that can "float" on top of a heaving,
yawing, pitching deck without transmitting those motions up into the lathe's bed.
(Guess this puts the common "Lathe Leveling" discussion to rest? -Level isn't necessary, "Twist-free lathe bed" is crucial)
"Simple, quick and cheap to make" sounded just fine to me, and as Providence would have it:
I had a scrap piece of cold-rolled RHS stashed at work, so I simply chopped away a 673 mm length from a 100 x 40 x 4 mm,
and welded two 10" pieces of hot-rolled 35 x 35 x 5 mm angle iron to the ends,
making the stand just a bit longer and wider than my lathe bed.
Rob also mentions that it's a pretty clever idea to lower the beam a bit below the end supports,
for cutting oil to follow the beam into the chip tray, rather than out and down the legs - so I adopted that.
Drilled the bolt holes thru the RHS, added 1 mm soft Al shim and bolted the lathe on - simple as that.
Check for headstock parallellism and bed twist will now hopefully be an uncommon practice...
(Edit: The line above is one of those "Famous Last Words"-lines you've heard about. See my reply below)
Sorry for the black Hammerite finish, and the barely completed 45 mm square plywood feet.
Reason for the wide footprint plywood stand is to provide for a wide, long and roomy chip tray,
that can be removed to any side, front or back.
I also chose to have two feet (rather than a monopost) at the tailstock,
as my "domestic workshop" is a wheeled workbench, and I don't particularly need the lathe to topple off it.
Here you also can glimpse my worm drive lead screw motor add-on:
Also my "Idiot safe" red yoghurt lid for preventing the machinist ( i. e. me) from accidentally engaging the dog clutch,
and the black grinding angle 20 & 8 deg for the hob cutter tool.