Specifications for birch timber for rotary cut manufacturing.
Rest according to GOST 9462-88. Round hardwood materials. Requirements specifications
Diameter of round timber: from 18 cm to 56 cm
Length of round timber:
|Payable length (m)||3,20||4,80|
|Overlength (m) from crosscut ends||+-0,02||0,10||0,10|
|Supplied length (m)||1,65+-0,02||3,40||5,10|
Knots: are allowed by 10% from a delivery lot (wagonload, carload) not more than 3 knots on 1 running meter. Knots must be cutaway (knocked off) even with the surface of unbarked round timber. Tobacco knots with the diameter no more than 7 cm.
End shakes: : are allowed with a depth of not more than the prescribed over length, being packed in a circle inscribed in the end with the size of no more than ½ of the diameter.
Sided shakes: are not allowed.
Simple sweep: is allowed with the ratio of the pitch of deflection in the place of the greatest sweep in the length of timber assortment in wood products to 24 cm - 1%, in wood products with a thickness of 26 cm or more - 2%.
Multiple sweep: is allowed in the volume of half the norm of simple sweep.
T disease, side drought, canker: are allowed outside the peeling area. The peeling zone must be at least 4 cm in radius from the inner surface of the bark to the center.
open wound scar, decay, central rot, cave rot, riffled buttress, mechanical defects, shatters which length is more than permissible length, which depth is equal or more than peeling area, burrs, double top.