22 BULLETIN 1436, U. S. DEPARTMENT OF AGRICULTURE 
Blocks dried out of doors will check more in summer than in 
winter, as will round bolts with the bark attached, particularly if 
exposed to the sun. The manufacturer who shields his raw material 
from rains and the hot sun of summer with an inexpensive but 
waterproof shed shows good judgment. Some manufacturers, in 
order to avoid seasoning difficulties and fungous infection in both 
bolts and blocks, do not cut their dogwood and persimmon dimen- 
sion stock in the summer months. This is very good practice when 
possible. 
Two by two inch shuttle blocks having in their green state a 
moisture content of from 25 to over 100 per cent of the oven-dry 
weight of the wood require about nine months of open-air seasoning 
to become what is ordinarily known as air-dry ; that is, to come into 
equilibrium with the surrounding atmosphere, averaging between 
12 and 15 per cent in moisture content. 
If all blocks were so uniformly seasoned as to be air-dry when 
shipped the shuttle manufacturer's problem of utilization would be 
comparatively simple. The block manufacturer endeavors to season 
his blocks as long and as uniformly as possible, but is often com- 
pelled because of rush orders for odd sizes which are not in stock 
to ship blocks some of which are practically green, or half air-dried. 
Several block manufacturers interested particularly in the export 
trade hold large quantities of blocks in storage houses near ports, 
where the blocks have opportunity to air season properly, 
AT THE SHUTTLE FACTORY 
The shuttle manufacturer seldom knows the condition of the blocks 
that he receives and frequently makes no careful effort to find out. 
To avoid waste and unnecessary loss, however, he should determine 
at once the moisture content of the incoming blocks so as to know 
exactly how they can best be treated and what course of seasoning 
they need. 
Most manufacturers are content to pile the blocks in an open 
shed or in some sort of seasoning room for a long period of time 
to be sure that when used the blocks will have reached an equilib- 
rium in moisture content. This would be very good practice if 
the manufacturer did not soon find himself tied up with thousands 
of dollars' worth of raw material unready for Use. The inventory 
of one modest shuttle factory on December 31, 1923, showed $86,000 
worth of dogwood and persimmon blocks in the process of seasoning, 
not representing excess purchases during the World War but pur- 
chases in the ordinary run of business. In such a system of sea- 
soning not only is capital tied up in the cost of the blocks, but also 
there is expense in the handling and rehandling of them, in the 
storage sheds and buildings required, and in the ground space the 
buildings occupy. 
The remedy for this is artificial seasoning or kiln-drying. Well- 
regulated kilns thoroughly understood by the operator will help 
to solve a problem which unquestionably is one of the most vexing 
in the manufacture of shuttles. Several manufacturers are already 
successfully kiln-drying shuttle blocks in much less time and with 
much greater satisfaction than with the long-time air seasoning. 
Some are using heated chambers, either with or without forced 
