I'm slowly getting the hang of user interface programming in python. It's quite the learning curve ! TK, python and windmill profile problems all at the same time.
The nicest thing just happened, I was wrecking my brain half the day over how to get things to register during the 'flip' between the first and second passes and a ready made solution just plunked into my mail box. Thanks Ron !.
Still one little problem to work out now, I don't have enough 'swing' under my z axis to lift the blade out of the jig as sketched that accompanied the email (not enough room under the gantry and it can not be removed). That's what you get for designing something with one use in mind, I never thought I'd be doing 6" high 3D profiles... I'll have to rework it a bit so one end can 'slide' into the jig and the second stop should be removable from the baseplate during the slide. still that looks like it won't be too hard. I also think that the jig will need some kind of horizontal bracing because I'll be cutting a composite (wood/foam laminate), and if there is just a little bit of foam (tabs, another suggestion from Ron) holding the whole works in place when it hits the plywood root section of the blade then I don't think it will stand up. Probably I'll just make a set of guides that I can place at fixed intervals and use blanks that are increments of those intervals wide. That way I won't need to make any sliding stops (it will waste some material in the blanks though to make sure they rest against the stops).
I also noticed an ugly jump in the cutter table when it passes the 4' mark, roughly the middle of the table. Some kind of jamming on the gear racks or maybe an alignment problem. no rest for the wicked. Hopefully tomorrow I'll get to do some cutting again.
I wonder what kind of dimensional inaccuracy is permitted in a set of three blades. The table is quite good but I did notice runout on the bearing of the router which is compensated by a spring pushing down on the end of the shaft. This causes a bit of chatter and it gives a noticeable roughness in the finish in steep portions of the cuts.