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Square Rule

From the Quicksilver Metaweb.

At it's simplest Square Rule is the Existance of the Theoretical timber within the Real.

An example would be, that a Post has the Actual Dimensions of 9" x 9"; that is the Real Timber.

The Theoretical is then a Choice which the Builder makes. Often times the convention was to go the next whole number lower. So that the size of the Imaginary Stick would be 8" x 8", but that is merely a "Rule-ofThumb", 81/2" x 81/2" may work just as well, depending upon how straight, how out of Wind (pronounced Wind as in Clock and not Wind as in Breeze), or what kind of flaws exist in the Timber.

Differences Between Square Rule and Scribe Rule Layouts

The Layup

Scribe Rule depends upon the sticks being laid one atop the other, in the manner in which they will co-exist when the structure is raised. You think about "Planes", when doing scribe rule. In the simplest building -- One with Four Outer Walls, all at right angles to one another, and no interior Walls; A Gabled Roof, of whatever Pitch, with a Principle Rafter, Common Purlin Configuration, with a Ridge; And Two Floors, one first, the other Second -- as either a Full floor or a Loft, In That type of a House there would be Four Layups for the Walls, Two for the Floors, and either Four or Five layups for the Roof, depending on how you laid the Ridge in. A Total of between Ten and Eleven Layups.

In the House Above there are,Two Long Sills, At least Two Cross Sills, A Number of Joists (The Actual Floor and Roof Structures are irrelevant for the purposes of this example), Four Posts, Two Tie Beams, Two Plates, Four Principle Rafters, A Number of Purlins, And a Ridge.

  • The Actual House might include More Cross Sills, Summer Beams, Door Posts, Girts, Braces, collar Ties, etc.

In this example Each Post would go into Two Layups, Each Tie into Two Layups, Each Plate into Two, and so on. This is because The House is divided into all of it's Planes, and the Posts, Ties, Plates, etc, exist in more than one plane.

The Actual Layup in a Gable Wall of the House above would be; Two Corner Posts, a Tie Beam, and a Cross Sill. They would be arranged in a Horizontal imitation of how they will eventually be standing. In this case, the outside faces of the Beams would be up, and their interior faces would be down.

One of the easiest ways to construct a layup is to do a Line Drawing of that particular section, the one you are about to Scribe, on the floor. The Timbers would then be lined, and set some distance above the floor in layers. This example only has two layers. The Posts are both in one, and the Cross Sill, and Tie Beam set upon the posts -- Raised slightly above them -- in a Second Layer.

Plumbs are then used to determine the relationships of one timber to the next, But The point of this Article isn't to teach Scribe Rule, it's to show that the Joinery is Absolutely concerned with the Actual Faces of the Sticks, And the location of each Joint is in no way an Abstract, Theoretical, or Mathematical Determination.

This is not so with Square Rule.

There Are no layups in Square Rule

Square Rule is said to have begun, in True Form, around 1805-1815 somewhere in the North Eastern States; New England. However, sometime in the late 1700's Scribe Rule was undergoing a Change; Rough Housings were being made Prior to layup, in the location where the Joints would be. In other words; The timbers were being reduced to a Theoretical size, however, the process for determining where the Joints were on the sticks was still being done through Layups and Plumb Bobs, Not through the use of Math.

In a Square Rule Building, No Two members of the Structure need ever see another until the day of the Raising. This was a Dramatic Change, and a Wholly American Invention. The placement of Each and Every Joint is determined through careful measurement. Each Stick is given a New dimension, and a reference Corner, from which that dimension would eminate.

In Scribe Rule, Two Foot marks and Zero Marks are Essential, and Utterly Vital, for timbers going into multiple layups; These are what would determine one Sticks relationship to the next from Layup to Layup. Without these Lines, there is no reference from one Plane to the next, and any alignment would be coincidental, at best.

There are No Two Foot Marks, No Zero Marks in Square Rule. There is no need for a "Scribing Floor", nor a Scribing Yard. There is no such thing as a "Square Rule" Yard. In Square Rule, Timbers may be cut in the least efficient, or the most efficient manner possible, for, neither effect the accuracy of the layout, merely the cutting.

Another Major Difference between Square Rule and Scribe, might already be very apparent. In Square, every potential joint may be layed out at once, in any order, as may each piece. A Rafter may follow a Sill, following a Corner Post, following a Plate. The Only dictates in Square Rule are that sizes be determined prior to layout, Or that there be enough slop to allow for future sticks which might be greatly Undersized, Hence, the choice of reducing a Timbers dimensions a Full Inch when going from Real to Theoretical. This was particularly relevant when dealing with Hewn, Pit Sawn, Riven, or other types of Conversion that might result in uneven, or, inconsistant sizing.