Another thing to remember is that the lines can get blurred between mill rule, square rule and mapping.
For example, we are currently working on our fourth truckload of band sawn cypress for a project. 80% of the sticks are 1/8" over dimension and the rest are within 1/16 of that. And they are dead square. It is very well-sawn. It would be absurd to reduce an 8-1/8 x 8-1/8 to 7-1/2 x 7-1/2. We either make the housings/mortises/etc 8 1/8 or we make them all 8 and reduce the tenoned members to 8". Is this mill rule? mapping? square rule? I don't really care. It's all the same. If the stock is consistent you don't have to be so heavy handed in your gains and reductions and the visual impact of "square rule" becomes minimal, but you are still laying everything out the same way. Braces and timbers that need bearing are housed a set distance of f the reference edge (or line) that will give us the bearing we need.
The one underlying principal in all of the above methods is that all timbers are laid out from a reference corner or if it is a crooked or twisted or hewn stick, it gets chalk lines that represent a reference plane offset a certain distance from the reference corner.
As Tim mentioned, a lot of this thread is talking about a very specific circumstance -- when you are working with very twisted and crooked and dimensionally variable timber. Making a twisted and crooked 8 5/16 x 10 3/16 join a twisted and crooked 7 7/8 x 8 1/16 and have it look decent. We run into it occasionally, but usually the timber is better than that.
Last edited by Gabel; 04/11/08 12:34 PM.
