How do I get a flat base....help

[Bonzo]

Nice informative post Mr H

I too used a tripod mounted laser level & as you say, 1,000 & 1 uses, very handy tool indeed

Me ?
Was lucky enough to have a stack of heavy duty 3" X 3" angle iron at my disposal .... Made a very sturdy frame supported by 6 legs, laid 3x2 timber accross the top, covered the whole lot over with water proof t&g floor boarding & finally capped the whole lot off with a full sheet of 2mm thick Zintec steel sheet ( Also laying about in the workshop )

It ended up as flat as you could expect in the home enviroment .... I expect that the wooden element of the table would have warped over an extended period but in my case the chassis went together quickly so I never had that problem to overcome

If you don't have loads of spare cash for expensive levels, you might be able to make good use of a plasterers feather edge.
Wickes do a good selection of them & some very long ones too .... They'll not tell you if something's level but it will tell you if it is all flat