last year I had about 200 sqm of oak boards restored and the guy used a german-made upright belt sander which was of a design unchanged since the 1950s. You are brave using only hand tools.
Brave - but I felt I had no choice. I just didn't want to trash the floor by over sanding with a big belt sander. On a design like ours I'd have to sand on the diagonal and there was no guarantee it wouldn't have torn up chunks of the floor. Replacement costs would have been massive over here so throwing my labour at it seemed wise. I estimate we saved around 10,000chf in me doing the work - or 1,100chf (after tax) per day
I used a Fein multi-tool and Metabo grinder and sander - the former stared to leak grease from the head when I used the diamond head when I was working on the leveling compound - but opening it up revealed no gear damage. Going out and buying professional quality kit was a wise investment.
While I was in the UK over Christmas I popped into the Algerian Coffee Shop on the Old Compton Road - they have a really old Swiss made coffee grinder!
@Roger - I rollered on the varnish (satin finish) and it makes the floor so tactile
. Although the house is now colder
