I have been working on the vertical and horizontal stringers. Most of them are 3/4x1/2" they are profiled/eliptical in the middle with the ends left square.
(See full size pic below)
Made first one by hand but very time consuming, Don Coe from the UK who has built a beautiful 1/3rd scale version (of which I will be stealing ideas!) used a belt sander and thought about going that way, but he mentioned pity that there is no machine available to profile wood like this and that made me think about my CNC router I built (after reading about them on here) a few years ago.
A friend suggested I try a "round over bit" and I made a few cuts with my hand router and found that the ¼" round over bit ran around all edges, left me with a near elliptical shape just needing a bit of sanding. Perfect, now get the CNC router to do it for me.
I got the CNC router to do two sides at time, then I was able to flip it over and do the other side. Also every pair of stringers are a different length, so the bevel/profile length needed to be adjusted in the Gcode to suit each time.
I made a Jig from some MDF and got the CNC to cut out a 3/4" slot, plus a location channel and fitted in some 6mm captive nuts at various places to clamp the wood down. Thought it was worth the bother as there are a good few to do.
Took a bit of time to get the starting/end distances correct for the first piece, but once set, the CNC does each piece in a couple of minutes, so got them all finished last night and they are looking good.
Also done a little video of the CNC cutting them Click Here to view video