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

Very cool. Are the circular feet old bearing races?
emunden2 years ago
Very cool. I would buy that.
this is the single coolest chair i have ever seen. awesome, just awesome