One of the most basic drafting exercises - find the midpoint of a line:
- From your subject line (red), strike an arc from the end of the line at any length greater than 1/2 of the subject line.
- Repeat from the other end of the subject line using exactly the same radius.
- Strike a line from the 2 intersections formed by the arcs.
- The resulting line bisects the subject line (and is perpendicular).
Attachment 367719
Yes, you can 'walk' this with dividers and trial-and-error, but the above method may be more useful and intuitive to some.
Stan - Thanks for this trip down old-time drafting lane.
PS - I recall reading somewhere that US tape measures are required to be accurate to +/- 3/16" in 6ft. So, two tapes could be off by as much as 3/8" in 6ft relative to each other. (always use 1 tape per project!)