The Chappell Universal Square incorporates an extremely broad number of new and unique applications never before available to carpenters in any form or format. Applying these comprehensive tables to the framing square marks the first truly unique improvement to the framing square in nearly 110 years, bringing the carpenter’s square into the 21st century.

The rafter tables on the standard framing square were developed at the turn of the last century and provide values to determine only 5 basic pieces of information: 1) length of common rafters, 2) length of hip and valley rafters, 3) the side cuts for the hip or valley and jacks rafters, 4) the difference in length for jack rafters for 2 spacings, 16 and 24 inches, and 5) the side cut of hip or valley. The Chappell Universal Square provides all of this information—and more—on the first line of the Equal Pitch rafter table alone.

A) Expanded Hip & Valley Rafter Tables

The Chappell Universal Square incorporates an expanded rafter table that gives 17 key values that include: 1) Common rafter length per 1 inch of run, 2) Difference in lengths of jack rafters per 1 inch of spacing, 3) Top cut of jack rafters, 4) Length of Hip & Valley rafters per inch of common run, 5) Difference in length of jack purlins per inch of spacing, 6) Top cut of jack purlins, 7) Sheathing angle offset per 1 inch, 8) Depth of backing & bevel angles per inch of hip or valley width, 9) Housing angle of purlin to hip or valley, 10) Hip & Valley side layout angle to purlin header, 11) Housing angle of hip or valley to principal (common rafter) and horizontal plate, 12) Working plane top of hip or valley, 13) Purlin Side cut angle, 14) Mitered fascia face
layout angles, 15) Hip & Valley backing angles, 16) Jack rafter and purlin top cut saw angle, 17) Fascia miter saw cut angles.

This is only on the first level. There are multiple levels to the values, which can be unfolded to determine joinery design and layout for compound mortise and tenon joinery and more.

B) Unequal Pitched Rafter Tables

For the first time in any format, the Chappell Universal Square provides comprehensive unequal pitched rafter tables that include: 1) Hip and Valley pitch in inches of rise per 1 inch of run, 2) Hip and Valley pitches in degrees, 3) Difference in length of runs side A to side B, 4) Length of Hip or Valley per inch of common run, 5) Difference in length of jack purlins per inch of spacing, 6) Top Cut of purlin, 7) Difference in length of jack rafters per inch of spacing, 8) Top Cut angle of jack rafters, 9) Backing and bevel angles in degrees, 10) Top Cut saw angles for jack rafters and purlins, 11) Purlin side face layout angle, 12) Fascia miter face layout
angle, 13) Housing angle of purlins to hip or valley, 14) Side layout angle hip & valley to purlin header, 15) Fascia miter saw cut angle for rafter tails cut at 90°.

This is also only the first level. There are multiple levels to the values, which can be unfolded to determine joinery design and layout for compound mortise and tenon joinery.

C) 6 & 8 Sided Polygon Rafter Tables

Again, the Chappell Universal Square includes a comprehensive polygon rafter table that is available for the first time ever in any format. The tables include values for 6 & 8 sided polygons with common pitches from 2:12 to 18:12, to include: 1) Hip & Valley rafter pitch in rise over 1 inch of run, 2) Length of common rafters per 1 inch of side length, 3) Top cut layout for jack rafters & jack purlins, 4) Difference in length of jack rafters per inch of spacing, 5) Length of Hip/Valley per 1 inch of side length, 6) Difference in length of jack purlins per 1 inch of spacing, 7) Sheathing angle offset per inch of board or plywood width, 8) Backing & bevel angles in degrees, 9) Jack rafter & purlin top cut saw angle, 10) Jack purlin side cut angle, 11) Mitered fascia face layout angle, 12) Jack purlin housing angle to hip, 13) Hip & valley side layout angle to purlin header, 14) Depth of bevel & backing angles per inch of hip width, and 15) Fascia miter saw cut angle for rafter tails cut at 90°.

These are also only the first level. There are multiple levels to the values, which can be unfolded to determine joinery design and layout for compound mortise and tenon joinery.

12/2012