Here I go out on a limb. I am most sure square rule was developed for sawn material. It was part of the transion to speed up the framing process.
As for Mo's first post and his question of the downside of square rule, Gable is right, Mo example is a extreme one. 98% of my work is square rule all off an edge, no snap lines. Some times they are nice and square other times out of square by up to a 1/4". You use the aris, the true corner of the ideal timber. I hardly ever see twisted or bowed stock which is unusable. Most of my stock is soft wood and reasonablely fresh. If it was to sit around for ten years and it was hard wood I would have issues. The old frames were more likly to have been cut green and more true. I will spend some time looking at Gable's last post with the Light and Heavy...... link, it sounds interesting. Tim
