UTILIZATION OF DOGWOOD AND PERSIMMON 
17 
wood free from heart checks or other ordinary defects there is no 
difference in strength. The sapwood of the young tree in turning 
into heartwood has undergone only minor chemical changes, chiefly 
oxidation, which darken it to some degree, but do not weaken it. 
The cell structure is identical, and there is no reason why the wood 
should separate where heartwood and sapwood meet. Unnecessary 
waste results when blocks are refused because heartwood is present. 
Most persimmon logs used by shuttle-block manufacturers are re- 
ceived by freight in gondolas or flat cars so that loading and unload- 
ing can be done readily. 
At the block mill the bolts of rough dogwood and the persimmon 
logs are cut off by a circular saw to the desired length. Considerable 
skill is required of the cut-off man in obtaining the maximum amount 
Fig. 10. — Ripping open the persimmon bolts 
of suitable materials and eliminating waste. A skillful cut-off man 
will eliminate crooks, will allow only clear material in the same 
pieces, and will detect defects which the unskilled man can not see. 
Small bunched knots, very undesirable in shuttles, cause slight irregu- 
larities on the bark, resembling from the outside the knuckles of a 
man's fist. They are detected only upon close scrutiny. The sec- 
tion in which they appear is alwa} 7 s eliminated in good manufactur- 
ing practice. An unskilled cut-off man in an effort to save material 
will overlook such defects and allow knots in the same piece with 
clear material. The whole piece must then be rejected when the 
knots are exposed by sawing. 
Bolts for blocks after being reduced to the desired length are 
generally sawed open by either of two methods. Some manufactur- 
ers saw the bolts into halves first and then into quarters (fig. 10) ; 
103115°— 26^ 3 
