Anyone have an idea what this "machine" was?

I recently lucked this work bench for a few quid....... the top is a single piece of cast aluminium 1300 x 730 of minimum 12-13mm thickness.
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Initially it will be used as a flat-ish and square-ish surface onto which parts can be clamped to weld together the frame for my upcoming CNC router build....... Because my dodgy back would never allow me to bend down and weld on the floor!
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I'm curious as to what it's previous life purpose might have been........ I haven't noticed any wounds from machining or grinding. Anyone have an idea?