by R J Willson and K C Woods
 
For Builders cutting roof frames on site. Designed not only to replace the steel square system but also to simplify the process of calculating rafter lengths and bevels and greatly reduce the risk of error. Expensive wastage is therefore kept to an absolute minimum. The calculations cover every roof pitch from 5° to 75° in 1° increments. Full details on the use of this simple guide are given in the Introduction to the book. The angles are clearly drawn in line diagram form allowing the reader to set up a sliding bevel quite simply and KNOW the result is accurate.