thanks MichaelAtz O and Marius The thing was a mish-mash of blender, inkscape and (mostly) openscad, importing stls etc. Sifting through dozens of files looking for where I made error. Your assurances that it isn't in openscad is very helpful and I'm looking elsewhere. BTW it's not the printer's fault it's obviously my fault. Finished object is quite good just wound up off size with visual proportioning done from wrong point. Take away for me .... even arty stuff ... keep better records and organize workflow better. Thanks again for helping me out, I'll keep digging.