- Lining: tracing, on two adjacent faces of a irregular timber, the projections of a line chosen to be the timber's axis.
- Counter lining: projecting those lines onto the two opposing faces of the timber.
- Square line (trait carré): line perpendicular to a given line.
- pièce de niveau: timber that has been leveled along its length.
- pièce de dévers: timber that has been leveled across its width i.e., has no twist.
- Reference area (plumée): small rectangular area on a surface which has been dressed (planed) smooth, [ so that a level can be accurately placed on it]. This serves as a reference for lining and counter lining.
- to plumb: to trace a vertical line from a point by using a plumb line.
- Choose a point i on the end of the timber. The plumb level is placed on this point. The vertical distance iX is transferred [across the face] to vw.
- [Draw Xw.]
- The reference is the horizontal edge of the plumb level, oo'.
- At the other end of the timber, choose a point i1 and perform the same operation. The plumb level is placed on i1 and the vertical distance i1X is transferred to v1w1. The horizontal edge of the plumb level is still used as a reference.
- Draw line ww1.
- On the far face, put the plumb line against point Y' and mark point g' on the line X'w' and t' on the bottom face.
- Draw line tt' on the bottom face [(after turning the timber so you can do this operation)].
Step 14, the final result
- The four lines XX', YY', ww' and tt' represent the projections of the timber's axis onto the four faces.
- The axis passes through gg'.
This procedure is directly applicable to assemblies in which the timbers' orientations are square to each other, like in roof trusses. In the previous post in the series on the French scribe method, we skipped directly to the "good stuff" of laying out timbers with twisted orientations. The lining procedure is still useful in that case too. Our example was the layout of a hip rafter and king post. The king post will also be layed out with rafters, so it will be lined in the manner described here. That establishes a central axis, seen here:
Note: I found many translations of French carpentry terms at Marc Guilhemjouan's pages on traditional timber frame techniques.