Re-varnish TeVe chair  

In the images showing the underside of your chair, there are two that look like hex(?)) bolts, is that how those metal rings in the back vertical wood parts attached to the seat? Maybe you just need to loosen those 2 to separate the back piece from the seat.

I was referring to item # 1 of your post that you described as a 10cm threaded rod.

You probably had done it already, remove/unscrew the back from the 2 vertical wood parts then unscrew or loosen the nut that looks like secures the metal ring part from the seat & the vertical back piece should just pull out of the hole into the horizontal back rail(?)

I did try that, but due to the glued joints at the bottom horizontal back rail it was not possible. I tried pushing the hex bolts (thanks, cool word!) out from the seat frame but I would