NOTE: I only provide webspace for Michael Nahl, I am not the builder of this bike!!
The bike is built out of tubing of womens bikes and mountain bikes. Nearly everything is brazed using 20-30% silver rods.
The pivot uses a bottom bracket. The bottom bracket (old XT) came in three pieces, two threaded cups for screwing it into the BB shell, and a middle piece containing the bearings and axle. Only that middle piece was retained. The diameter of that middle piece is 30mm which fits nicely into a steering tube. This was pressed in and fixed with a bolt. The sealings are taken from a VW T4 van (steering rod ends).
Seat is challenge seat clone, 3mm aluminium, using rivets.
More photos can be seen at HPV Sverige.