SCALING 41 



give the total defect for the lojj;. It will be noted that the ro(. formula is 

 similar to the pitch seam formula except that the width of the defect is 

 taken as equal to the diameter of the rot. 



Slab. — Western red cedar logs in the course of handling very often si)lit 

 up into slabs which can not be acciu*ately scaled as logs. The method used 

 on the Pacific Coast in this case is to estimate the volume of the slab in 

 shingle bolts and reduce this volume to feet B.M. by the formula given 

 above. A ''shingle bolt " in the formula is a piece 52 inches in length with 

 roughly, equilateral triangular ends, the sides of this triangle being 12, 14, 16, 

 or 18 inches in length. To determine the number of feet B.M. in a shingle 

 bolt, first measure the end and compute the area of it in square inches, then 

 multiply by the inches m length and divide by 144. Multiply this result by 

 .70 and the result will be the number of feet B.M. in the bolt. 



Example: How many feet B.M. in a bolt 52 inches in length which has 

 a triangular cross section 18 inches on a side? 



Area of triangle (18 by 18 by 18) X 52 ^ ^ , , 



X./0 = 35 feet B.M. 



144 



Miscellaneous Defects. — The formula? just given for seams, rings, and rot 

 can be applied to nearly all other interior defects. There are, however, 

 several other types of defects to which they do not exactly apply, such as 

 crook, cat face, sap rot, worms, broken ends, etc. Allowance for crook can 

 be made by a lump percentage of the total contents of the log or by deducting 

 the equivalent of the piece of lumber which it is visualized would be lost. 

 No allowance is made for cat face or similar side defects unless they extend 

 inside the cylinder represented by the top diameter of the log, in which case 

 the equivalent of the piece of lumber lost should be computed and deducted. 

 Allowance for sap rot will be made by scaling the log with a diameter inside 

 the exterior decay. Worms and broken ends can be allowed for by reducing 

 the length of the log sufficiently to eliminate the defect. 



Method of Using Scaling Tables 



In order to simplify the application of the method to actual scaling, by 

 means of the scaling formulae, the tables on page 42 have been computed 

 to show the defect per lineal foot for the most common sizes encountered in 

 scaling. A copy of these tables should be carried by the scaler for reference 

 at all times. 



Included with the scaling tables is a legend for use in indicating on the 

 scaling sheet (Form 5) the kind of defect found in each log. This legend may 

 be used as follows: 



If a log has a pitch ring, use the letters P. R. as show^n in legend instead 

 of writing the words in full. 



If a log has a pitch seam and ground rot, use the letters P. S. and G. R. 



If a cedar slab is scaled, place the letters SI in the defect column. 



