Office Armchair
I found an old armchair workshop ...
it was not in good condition and I height adjustment system was broken (threaded rod)
I was inspired automotive jacks for height adjustment system
I asked a friend to make me custom gears to have a perfect parallelogram whatever height
there is a screw-endless of jacks and an old crank to raise the siege
the springs after the screws allow the seat cushion
there are thrust ball bearing, for the screw and the rotation
I deliberately kept as-is the seat and backrest
I also remanufacture legs
the old seat of the first photos will be restored later
it is to show you what state was the black in this Instructables
it was not in good condition and I height adjustment system was broken (threaded rod)
I was inspired automotive jacks for height adjustment system
I asked a friend to make me custom gears to have a perfect parallelogram whatever height
there is a screw-endless of jacks and an old crank to raise the siege
the springs after the screws allow the seat cushion
there are thrust ball bearing, for the screw and the rotation
I deliberately kept as-is the seat and backrest
I also remanufacture legs
the old seat of the first photos will be restored later
it is to show you what state was the black in this Instructables