Posted by georgesbasement on Aug 07, 2017; 10:00pm
URL: https://forum.librecad.org/Trimming-unwanted-arcs-from-a-circle-tp5715167.html

Progressing to the second drawing of my new career as a LibreCAD draftsperson ...

My project now involves a bracket made from quarter inch thick plate that consists of a circle flattened on top and bottom and having a narrow arm extending up and to the right at about 45 degrees.

The circle and its arm are there, and the arm even has a 180 degree rounded end. The circle has not quite complete lines across the top and bottom that I haven't been able to force to snap to the arc of the circle, except at two points where the arm intersects the circle. Once those four intersections are pinned down, I'll need to delete the three unwanted segments of the circle: top, bottom and inside the arm.

I almost did it with the upper arc of the circle, but when I used the trim command and first selected the line defining the top of the soon-to-be-truncated circle, when I next clicked on the unwanted part, the whole bottom of the circle was removed, i.e., the exact opposite of what I intended. I tried my trim selections in the opposite order, but got no effect at all.

When I tried Trim Two on the arc within the arm, alas, the lines of the arm and the flat bottom of the circle were extended to intersect with each other. The arc of the circle was ignored.

When I tried Trim on the bottom arc of the circle, the exact same result occurred, with only the sliver of the bottom of the circle remaining.

These two Trim options seem to be doing the opposite of what I intend, as already suggested in other places in this excellent forum.

Help is welcome !
georgesbasement