... screw tops should be raised and embossed with a code letter. But we have to draw the line() somewhere. 2_270623_540000000.png 2_270639_170000000.png Keys next, I think. Martin. posted: 28 Jul 2018 17:26 from: Martin Wynne Hi Andy, Looking at the L1 drawing with my eyes open this time, I see that the L1 seat marker was wrong. The actual seat length is the same as the S1 (7.7/8 "), not the full width of the chair. I have modified it: 2_281210_190000000.png Notice also that I have now given the pan skirts on the screw heads a finite edge thickness. It's yet more stuff in the file, but they looked wrong without. They also have a flat underside to seal against the top of the ferrule for 3D printing. Here's a bit of DXF file attached for you to experiment with replaced blocks, containing only the timbers and markers: 2_281210_500000000.png Block datum is the rail gauge-face, chair centre-line, z=rail top (so all z dims negative) ...