The design calls for a central timber that the stairs can fix on to. BUT I wanted it to look good and so did Wendy. Therfore:
Thirteen slots to take the risers need to be cut in the square post 100 x 100mm at exactly the right angle. After much designing I made a jig to take my router, by unbolting and moving the matal slider frame round the pre-drilled holes I could get the right angles. The carrier for the router fitted both ways in the frame and was sized so that turning it through 180 degrees gave me the right width of slot. The frame was sized to give the length of slot with screws in the router carrier for fine adjustment.
It worked a treat.
Next I wanted an Acorn on the top to match the existing newels. None are available off the shelf so how to make one? and do really want to just stick one on the top.
NO make a 14 foot long lathe
By using a router to do the cutting I don't need to spin the timber fast. So one pivot on the garage door and another on the Workmate, a jig for the router and I'm all tooled up. Almost
Spining by hand is a little tricky while guiding the router so I made it into a foot operated pole lathe, with a motorbike inner tube as the return and tensioner a piece of rope and a bit wood for the treadle.
I was enjoying it so much I carried on and turned the complete newel.