How many pieces of unedged boards are in 1 cube?

Calculation of the number of pieces of unedged boards per cubic meter of wood is required when calculating the costs and the amount of building materials for finishing and reconstruction of a building. The number of pieces of unedged wood will also be needed to select the final cutting width of the same boards.

Before starting the calculation, pay attention to the following factors.

• Wood moisture - in comparison with it, dry is slightly compressed due to the departure of a significant part of the water from the volume. An everyday example is the swelling of wooden doors and windows in a bathhouse: the sash, which opened freely yesterday, today after using the bath (due to high humidity) sticks and moves with difficulty.
• Diameter of trunks to be cut: with significant fluctuations in this value, an unedged board during side cutting will give a significant amount of waste.

The weight of a cubic meter of unedged board is a secondary factor that is more important for the supplying company than for the consumer: a large tonnage will require more machines and higher costs for motor fuel. The weight depends on the type of wood, the moisture content of the dried workpieces, the size of the board.

Before the actual counting, the unedged board should not be stacked randomly. Even when the workpieces lie flat on the sides and are not parallel to each other - they are not adjacent, but can be located perpendicularly, the air gaps in the stack are minimized. The limiting airspace ratio in an unedged board should not exceed 9%. If it exceeded this level, then the blanks were not quite similar. Having found this discrepancy, the manager or the warehouse manager will instruct the loaders to double-check the stack. Those will remove blanks from it that differ from the size tolerance limit. The point is that customers pay for wood, not air.

Having a limited amount of space given for the stack - for example, the same 1 m3, 6-meter boards should not differ in average width. For example, it is impossible to place specimens 4 and 6 m long in one pile of unedged blanks - as well as 20-30 and 40-50 cm wide, as well as 2.5 and 3 cm thick.The latter is taken from the table of denominations available in the warehouse catalog or a logging base where unedged material is purchased.

As an example - unedged blanks with dimensions 30x150x6000 and 50x150x6000. They are often found in the catalogs of most logging yards. A simple calculation using a simplified formula, without having to re-measure each piece in a stack, looks like this:

• it is logical to assume that the width tolerance is 145-155 mm in both cases. the volume of the board is 0.027 and 0.045 m3, respectively;
• the number of whole blanks per cube - 22 and 37 whole pieces;
• arranging them in stacks - per cubic meter - we get, taking into account the airspace not covered by wood, 20 and 33 pcs. in the worst case (taking into account 9% corrections for air).

Before starting the calculation, know the following:

• when sawing a trunk into strips of unedged boards, according to statistics, up to a fifth of the timber is used for sawdust and trimming;
• the purchase is carried out taking into account these 20%;
• receiving a cubic meter of edged board, the amount of unedged board is brought to 1.2 m3 by volume.

The following GOSTs are taken into account:

• 13-24-86 - regulates the methods of calculating the volume of unedged wood strip;
• 65-64-84 - measurements of lumber (and other features of their balance in production).

Unedged board is an element obtained by sawing wood from a freshly cut trunk in two of three dimensions. These two dimensions are layer (cut in length) and section (in thickness). In this case, the width remains arbitrary.

The thickness is calculated by the bar according to the standards of the above-mentioned GOST. For measurements with a caliper, the 166th GOST applies, for measurements with a ruler - 427th. Thickness measurements are carried out no closer than 15 cm from the cross-cut. The length is calculated with an accuracy of a centimeter - using extra-long (from 6 m) tape measures or using clamps and a high-precision laser rangefinder.

To measure the width of unedged boards, on each of them, the largest and smallest natural widths are preliminarily taken into account, the values ​​of which were formed by the time the tree was cut down (and its trunk was removed from the branches). Add both values ​​and divide the resulting sum in half (get the arithmetic mean).

Despite the apparent simplicity, according to GOST 13-24-26, a sample of the number of pieces of edged board per cubic meter is used, taking into account the moisture content and the type of wood being processed. For this purpose, correction factors are adopted equal to 0.96 for conifers and 0.95 for deciduous species. The moisture content of the wood is at least 20% (by weight of the tree). Thoroughly dried wood, the amount of moisture in which does not exceed 1/5 by weight, does not take into account these amendments. The approximate number of unedged blanks per cubic meter can be calculated without exact measurements of each of them (which would take a lot of time).

For example, having the dimensions of a stack of 2 * 2 * 3 m, in which there is a pine board, dried to 12%, with a thickness of 2.5 cm, the client calculates the volume of the stack equal to 7.92 m3. With a spread in the width of the board of 10-15 cm, we get a total (approximate) number of blanks equal to 844 unedged boards. The number of products per cubic meter is approximately equal to 106 pieces. The resulting numbers are rounded to the nearest unit - downward. The variable value of the width should not differ by more than 10 cm.This does not mean that at the ends the width of the unedged workpiece diverges, for example, from 20 to 35 cm.

To this end, taking into account the structural features of a real living tree, too tall, for example, pines that have grown to 12 m, are sawn longitudinally in half. The trunk is measured and cut into two 6-meter blanks: subsequently, the loader can load faster (and the sawmill is easier to process) shorter sections of the trunks. A variant is possible when 12 m of the same pine is sawn into 3 4-meter sections. It is more difficult to cut a 24-meter overgrown pine - it is divided into similar segments, then they are sawn lengthwise. This is necessary so that the process of manufacturing unedged boards fits into the same tolerances of variable widths of unedged blanks formed during wood processing.

Trunks that have received significant differences in diameter - more than 10 cm for every 4 or 6 m, are rejected and go to the manufacture of other blanks other than a board, for example, cubes, sticks or parallelepipeds. Or they go to the shredder - for example, to make pine chips. Aspen, which has a significant difference in the specific width of trunk fragments, is transported, for example, to a match factory.

Determining the number of boards per cubic meter of unedged timber is a task that the client himself can solve. The company manager will check and, if necessary, correct these values ​​for quick order execution.

For information on how to calculate the cubic capacity of a stack of unedged boards, see the next video.