General Homemade Welding clamp deep - Home-made

In need of clamping long runs of floor plate over a deep sill, and reaching in almost a foot in places, I spent a couple of winter evenings making up a strong deep 'G'-clamp, using various box and channel sections, together with an old G-clamp screw, that had lost it's pressure cup.

Subsequently I made a fork that the screw-thread ball locates in, so that the weld can take place between the two tines, the floor being clamped very firmly barely an inch away either side.