THE GLUING OF WOOD 21 
a closed side. Most of the important hardwoods and some conifers 
are cut extensively by this process. Kotary-cut veneer is produced 
in thicknesses ranging from about three-eighths to one one-hundred- 
and-tenth of an inch. 
Sawed and sliced veneers are used principally for faces in ply- 
wood and veneered panels. Rotary-cut veneer is used principally 
for face stock, for thin cores (five-sixteenths of an inch and less), 
for cross-banding, and for curved laminated members. (Figs. 3 
and 17.) Most veneer, which is glued, ranges in thickness from 
one-fourth to one thirty-second of an inch. Yeneer thinner than 
one- fortieth of an inch is difficult to handle during the process of 
gluing because the water in the glue curls the sheets. Ordinarily 
one-fiftieth of an inch is the minimum thickness of veneer for suc- 
cessful gluing, although some Spanish cedar one one-hundredth of 
an inch thick is glued for cigar boxes. 
Usually surfaces of veneer are somewhat rough and irregular. 
By careful cutting, however, veneer can be secured that is compara- 
tively smooth and firm on both sides. Veneer is not usually re- 
surfaced before it is glued, and the care with which it is cut Js 
therefore of importance. 
In gluing operations where full-sized sheets of veneer are avail- 
able, the sheets may be glued immediately after drying. Cutting to 
size is preferably done before the final drying. Cutting after dry- 
ing allows more opportunity for the veneer to reabsorb moisture 
from the air. Furthermore, very dry veneer is easily damaged and 
should therefore be handled as little as possible. 
Wherever a face (fig. 3) for a high-grade veneered article is made 
of two or more pieces of veneer, careful jointing of the edges of the 
veneer is necessary to make the joints inconspicuous. This type of 
joint is made by placing the dried veneer in piles of several sheets and 
then running the piles over a special veneer jointer which makes the 
individual veneer edges smooth and true. These sheets are then laid 
in the desired position, and the edges are taped tightly together by 
taping machines. 18 It is good practice to glue the edges of the veneer 
together after taping. This is accomplished by folding the two sides 
back over the tape, coating the exposed edges with glue, and then 
bringing the edges together again. Laying the freshly glued sheet 
in a slightly curved form with the tape on the convex side insures 
that the other side of the joint is held tightly together while the glue 
sets. 
For cores (fig. 3), crossbands, backs, and in low-priced articles 
even for faces, extreme accuracy in jointing the edges of the veneer 
is not necessary. Jointing in such cases may therefore be done 
satisfactorily on a veneer clipper. In certain low-grade panels, 
where thick veneer cores are used, the veneer sheets are merely laid 
in position without fastening of any kind. The spaces between the 
pieces or the lapped edges, which often result, are of minor impor- 
tance in the grade of panels being manufactured. 
18 There are devices for edge gluing veneer without the use of tape, but an entirely sat- 
isfactory machine for the purpose is not known. Staples are sometimes used to hold the 
edges of thick veneer together. However, it is difficult to avoid cutting into the staple 
during subsequent machining. In European countries a device is used for jointing core 
and crossbaod stock which cuts a dovetail design in the two edges to be joined and fits 
them together without glue or tape. 
