Bones_Daley:
The thickness planer cuts a duplicate of the surface on the reverse side of the board …it does NOT , of and by itself, create a plane surface.
If the reverse side of the board is warped, or twisted, then the thickness planer will produce a warped or twisted face on the freshly machined side. If the reverse side of the board is plane to start with, then, of course, the thicknesser will produce a plane surface on the freshly machined side.
My beef with the nomenclature is that you cannot take a roughsawn board, feed it straight into a so-called PLANER [US] , and get a plane surface. Hence the reason why we don’t call them "planers " over here, and why we call the machine which actually generates an initial plane surface a “planer” (which in the USA you term a joinTer)
I just know somebody is going to jump in and explain that you ***can ***actually generate an initial plane surface using a PLANER [US] and yes, you can, but it’s a bit of a longwinded procedure …
I agree which is why I said it “creates a flat and level surface on one side of the board in relation to the flat and level surface on the opposite of the board that was created with the jointer.”