Since the pieces don't fit in the turning machines that are available to me, I had to think about an alternative method for the downtube to bottom bracket connection.
I decided to laminate a smaller piece, four stacks, with two stacks sticking out enough for a solid lamination. Then, laminate and glue the rest on there. The first picture below gives an impression of my description.
Remember, two pieces can easily hold my weight in the direction of the weaker 10mm (flat) side on a distance of 40cm.
Top tube to seat tube connection will be made fit by drilling. The steel section is 1 inch in diameter. Alignment and a drilling jig is key.
Four pieces fully sanded! A lot of work to get the hard white glue off.
First lamination piece!!
The 'four stacks high' bit will be round 32mm when I am done wood turning. And it will fit inside the frame tube there.
I will glue and rivet/screw it after alignment in the frame.
I wonder how the rivets in the below picture you sent earlier, are expanded in the wood. Is the wood that hard or the rivets that soft?
Or are they held in by a weld or even a tight fit in the wood?