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Front of Pile

If lumber is not evenly trimmed, it is evenly piled at the front, leaving the raggedness at the rear, and the rear sticker must be set to catch the shortest ends. In eastern and southern softwood piling the rear sticker is sometimes placed a foot or two back from the end, and this is also quite common practice in piling many hardwoods.

The practice is sometimes followed of setting out every tenth sticker at the rear end to project 4 to 8 inches beyond the ends of the lumber, as a drip board, using a wider sticker if necessary. The purpose is to reduce the amount of rain that can get into the rear sticker crossings.

Of the questionnaire replies, 53 indicated the placement of rear stickers, and 16 showed that they were placed flush, 23 with some projection, and 14 that they were placed back from the ends of the lumber. Two replies indicated the projection as slight, and one as half the width of the sticker. Of the replies indicating a recession from the end of the lumber, 7 stated a distance of 3 inches or less;

Back of Pile

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FIGURE 20. Sticker aligning device for outdoor piling, consisting of a light straight strip with hardwood dowel pins secured in holes bored in the strip. The pins must be sloped to match the backward slant of the pile and its forward vertical pitch. Pins are selected for the spacing desired and hold the projecting ends of the stickers firmly so they can not jump out of place when the first boards are laid. A device of similar fashion can be made for kiln load piling but would have the pins set perpendicular

back 4, 6, 8, 12, and 18 to 24 inches, 1 reply each; back 24 inches, 2 replies.

In southern pine only 1 reply shows a projection of the rear sticker 1 inch, while there were 9 replies showing placement flush with the ends and 8 showing its location back 2 to 24 inches from the ends of the lumber. In the California pines the sticker is flush in 1 reply, projected in 9, and back 2 inches only in 1. In all the replies received for redwood the rear sticker was projected and either flush or projected in all for western (Pondosa) pine. This was also true in 6 out of 7 reports for southern hardwoods, and for 3 out of 5 reports for northern hardwoods.

Accurate placing of stickers by hand requires labor, and they often get out of place as boards are laid down on them. A mechanical spacing device gives quicker service and holds the stickers more securely. A simple but effective device for yard piles is shown in Figure 20 and explained in the cut lines. By placing the pins square instead of at angle the device can also be adapted to piling kiln loads.

SORTING OF LUMBER FOR GRADES, WIDTHS, AND LENGTHS FOR PILING

Lumber is usually separated completely by grades at the sorting chain before it is taken away for piling; and in softwood lumber, at the larger mills, there is usually a fairly complete separation by widths and by lengths, since this separation usually appears in sales and shipments. Hardwoods are usually sold in mixed or random lengths and widths, though there has been a movement during the past years for their marketing in specified widths. Most hardwood piles, however, contain random-width lumber, and separation for length is usually group separation, such as 8-foot and shorter, 10 to 12 and 14 to 16 foot. In the smaller softwood mills it is not possible to make as complete separation as at the larger mills, because the slow accumulation of some items takes too long to complete a pile; and different items may be thrown together for piling even though they must be separated in shipping out, and thus add to the cost of handling.

In the 56 questionnaire replies giving evidence on this point 43 mills sort lengths in some grades, representing all species; 5 mills sort lengths in their entire product, all being southern pine mills; and 8 do no sorting of lengths before air-drying, including redwood, southern and northern hardwood and hemlock, North Carolina pine, and southern pine. The grades for which mixed-length piling was indicated were shop and factory lumber, 4 mills (2 redwood, 1 California pine, and 1 cypress); export grades, 2 mills (southern pine); standard redwood, 1 mill (redwood); dimension, 2 mills (California pine and Douglas fir); No. 3 common and poorer, 5 mills (southern pine); No. 4 common and box, 7 mills (2 California pine, 3 southern pine, and 2 Pondosa pine); 12-foot lumber and shorter, 2 mills (southern hardwood and North Carolina pine).

Where two different lengths are combined for piling the bulk of the lumber is usually in the shorter length, and this is allowed to determine the length of the pile. The longer boards project or overhang at the rear, where they get more wind and sun and are free to check, warp, cup and twist. A good deal of this additional damage is tolerated, and it forms one of the heavy sources of degrade in yard seasoning; but if the species is one in which occurs a specially heavy degrade if piled this way, some other method is resorted to.

BOX PILING

The most available expedient is box piling, which is more generally used in dry-kiln piling but could be more widely used to advantage in outdoor piling. The pile is made the length of the longest lumber, and the outer tiers are built of this length, also such proportion of the inner tiers as is necessary to take the proportion of this length. The short lumber is built into separate tiers, piled flush at the front, and with a second sticker line at the rear to support the rear ends of this shorter length. Each tier is built up of its own length of lumber, so that wherever the rear end sticker

supports the end of a board above it is in turn solidly supported by the ends of lumber below. Figure 21 shows arrangement of a box-piled layer, with short ends all at the rear.

Practical box piling requires a fair proportion of the longest lengths of lumber. The rear stickers afford a certain amount of protection to the lumber ends and hold the long lumber secure against excessive warp or twist. It is reported as not wholly successful with a few species, because of the excessive degrade in the rear end of the pile from end checking, dote, or stain; but it is difficult to understand how such damage could exceed that which occurs to

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FIGURE 21. -Arrangement of long and short tiers of lumber in box piling. As far as possible, tiers should be kept the same length, and if necessary to pile longer lumber over short, the ends should be blocked up to give solid end support to the ends. In yard piling all tiers are usually laid flush at the front, as shown; in kiln piling the short ends are placed at either end

projecting lumber ends in the other method of piling. This is a matter which every lumber manufacturer should test for himself; practically the only added cost of piling is represented by the added sticker line.

The questionnaire replies show that 55 mills are using box piling for mixed-length lumber. A few of these modify somewhat the method of full box piling. In some instances they mix different lengths in the same tier; in others they leave ends of short lumber overhanging without end-sticker support in the interior of the pile. Such ends, of course, can not sag more than the thickness of the missing sticker before striking the board below and thus can not develop very serious warp.

SPECIAL PILING IN PILE BOTTOMS

There has already been casual reference to this matter, such as use of thicker stickers or wider spacing in the bottom of the pile, but it needs special attention with reference to prevailing conditions in the individual yard. It may be that in piles as taken down the moisture difference in different portions of the pile may be under 3 per cent; but under other circumstances, with some species of wood differences close to 10 per cent may exist. Fast-drying species tend to come to a fair uniformity throughout the pile in the later stages of air drying; with slow-drying species the time required for fair seasoning in the bottom inner portion is so much more than for the rest of the pile that special expedients to hasten drying in this portion of the pile will be profitable. This is especially true where stain damage is involved.

The special piling remedies for slow bottom drying are (1) high pile bottoms and freedom from weeds and other ground rubbish that hinder air movement near the ground; (2) wider spacing between boards; (3) a flaring center chimney, widest at the bottom, or several narrow chimneys, which as far as their effect on the bottom of the pile is concerned need not be continued up through the entire pile; (4) thicker stickers in the bottom of the pile; (5) occasional courses of doubled stickers to give more horizontal circulation and to supply the pile bottom with more fresh air from outside and less of the damp air working down from the upper portion of the pile; (6) taking tops and leaving bottoms to dry longer; (7) repiling bottoms on tops of other piles.

In the western air-seasoning studies the use of chimneys was rated the most important influence on bottom seasoning, and the use of occasional doubled sticker courses ranked next in importance. Any method of opening up the pile bottom results in less lumber being piled in that portion, which is desirable. Here again the individual manufacturer can with profit conduct some tests for himself, provided he is sufficiently troubled with slow bottom drying to make it worth while. He may not know just what conditions prevail in this respect in his yard unless he makes some actual moisture tests.

Slower drying in the bottoms of piles was admitted as constituting a difficulty in only 11 of the questionnaire replies, chiefly in California pine and southern pine and to a smaller extent in redwood and in southern hardwood. The remedies actually reported as giving relief were: Raise pile foundation, 1 (redwood) mill; double stickers in the bottom of the pile, 2 mills (California pine and southern pine); double stickers each tenth course, 5 mills (3 California pine and 2 southern pine); double sticker courses each third of the height, 1 mill (California pine); wider spacing of layers in bottom of pile, 1 mill (southern hardwood); vertical vents in pile, 1 mill (southern pine); take tops first and let bottoms season 10 to 30 days longer, 2 mills (southern hardwood and California pine); repile wet bottoms on tops of old piles, 1 mill (southern pine). One southern hardwood manufacturer stated that, owing to the complex separation of the product into species, grades, and sizes, the piles accumulated so slowly that the bottoms get considerable additional drying before the piles were completed.

PILE ROOFS

Where lumber piles are roofed the roof is generally composed of the same kind of lumber that is in the pile, and the roof boards are laid on crossers usually elevated more at the front to give the roof more slant, than the rest of the pile. The roof is put on in a double layer, the second layer covering the openings between boards in the first layer; and the roof is also usually laid in two sections, the first one moved down so as to overhang at the rear of the pile, and the top section moved up to overhang at the front of the pile, and of course considerably overlapping the other section. The roof crossers are also usually longer than the width of the pile, so that the roof can be laid to overhang somewhat at the sides.

There are numerous variations from this type of roof. A great deal of lumber is piled without roofs, especially in lower-grade stock. Much upper-grade lumber is roofed with low-grade boards; and where such special boards are supplied for the roof it is often possible to use longer boards so that they will overhang the pile front and rear without laying the roof in lapped lengths. A good many roofs are also laid in a single length corresponding to that of the pile itself, with no overhang at the ends. Sometimes with such roofs the length is supplemented by a cross drip board at the rear.

One reason for elevating the roof somewhat above the top layer of lumber is to give the pile better top ventilation. As the roof itself is closed against air circulation through it, the only air that can circulate downward through the spaces in the top layers of lumber is that which gets into the pile from the sides under the roof. The only test of the effect of height of roof on pile depreciation found in the airseasoning reports appears in the Inland Empire study, where it was made on No. 2 common white pine 2 by 8, 16-foot. In the piles with roofs respectively 1, 6, and 10 inches above the lumber the degrade losses per thousand feet were respectively 45, 57, and 40 cents, and the losses from end trims were respectively 3, 3, and 6 cents. The pile with the 10-inch roof had more season check and loss of trims by end checking than either of the other piles, in both the top and bottom of the pile, though less than either of them in the middle of the pile.

In other air seasoning studies on the west coast it was shown that degrade was considerably heavier in the boards used for roof boards than in the pile contents, as might be expected from their exposed position. For this reason the use of special low-grade boards for roofers, using them over and over until they become too depreciated to be useful, is often good economy. Such boards often take a more or less pronounced cup, which adds to their value as roofers. If knots loosen or fall out, or open checks or splits develop, these defects will let water through, and boards should be discarded when they reach that condition. The chief function of a roof is to turn rain out of the pile, though its function in protecting the top lumber from discoloration and surface checking by sun and wind is also useful.

Of the 60 questionnaires replies covering this subject, 24 report the use of special roofs, while 8 have self-roofed piles with the same lum

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