Teak conversions
All sawn teak fall in the category of teak conversions. Before the 2nd World War, millers and shippers used their traditional grades which were known and accepted at home and abroad. The State Timber Board (STB) was formed after the independence to take over extraction, milling and marketing of teak. The STB had to find a common ground among the traditional grades offered and prepared a fresh set of rules by setting out to find grades common to the traditionally offered grades. The rules for teak conversions now in use are being prepared by the Forest Department on FAO lines, based on the practices of the State Timber Board.These rules divide the specifications into two: viz., the General Market Specifications (GMS), and the Special Market Specifications (SMS). GMS includes planks, boards, flitches, etc., that are intended for reconversion. SMS applies to decks, margin planks, and special sizes of scantlings that are to be used without further cutting.
Defects are mainly the same as in other products; but also includes those found after sawing. Bark pockets; beeholes; black streak or oil streak; blemish; chalk pockets and veins; checks; end splits; wavy, curly, rough, and cross grain; knots; sapwood; shake; spring; sun cracks; and wane comprise the list of defects.
Grades recognized in the rules are - Select Special; Special; Selected First; First; Second; Market. But in actual practice only Special & Better (S&B); Special (S); First (F); and Second (II) are usually sold. Specifications of teak conversions are shown in Table 13.
Specifications of teak conversions
| Specification | Measurement | Grades Available |
| Posts | 6”/9” × 6”/9” × 6' & up | F, II, M |
| Planks | Avg. (3.5” × 8” × 8') | S&B |
| Boards | 0.5”-2” x Avg. (8” × 8') | S&B |
| Flitches | 3” & up x 7” & up x 6' & up | S&B |
| Decks | 2”-3” × 4”, 5” × 10' & up | S&B |
| Scantlings | 0.5”-5” × 1”-6” × 1' & up | S, F, II |
The above mentions only the general groupings. Quality names as well as specification names also differs with those of other rules. Some of the terms used in the softwood and hardwood trades like baulks, battens are not used here.
Conversions should be well-manufactured with cross sections rectangular throughout. They must be sawn full with 1/8” overcut full to the normal dimensions at the time of milling. The permissible defects of each grade for teak conversions are briefly explained in Table 14. The width (W), length (L) of the piece is usually considered in calculating permissible defects. In knots the diameter (dia.) of the knot is taken into account.
Table 14. Teak conversions grades and permissible defect
| Defects | Special | First | Second |
| Knots (kn) | L<6'-one 3/4” L>6'-two 1/2” | one 1”+ one 1/2” | one 1.25”+ one 1/2” +one 3/4” (If knot unsound dia. is halved) |
| Bee-holes (b.h.) | L<6'-one 3/8” L>6'-two 1/4” distance<30% of L | two 3/8” distance<30% of L | two 1/2” distance<20% of L |
| Knots + Bee-holes | one kn 3/4'+ one b.h. 1/4” | one kn 3/4'+ one b.h. 3/8” | one kn 1.25”+ one b.h. 1/2” |
| Sap | W>4”- 1/2”×1/4” if 1 kn or 1bh W<4”-1/2”×1/4” | W>4”- 1/2”×1/4” if 1 kn or 1bh W<4”-1/2”×1/4” | <33% of width if free from other defects. if defects present same as FQ |
| Curly\Wavy Grain | <5% of pcs | <10% of pcs | allowed |
| Sun-cracks | not allowed | <1/8” on <30% of length <15% of pcs | <1/8” on <50% of length <15% of pcs |
| Pitch\Bark\Chalk Pockets | not allowed | three - small <3/8” dia. if oval; or 1”×1/8” <15% of pcs | four <1/2” dia. if oval; or 1.5”×1/2” |
| Black\Oil Streaks | permitted | allowed |
Squares / Conversions
The Grading Rules for Teak Squares, when read in comparison with the Grading Rules for Teak Conversions, will show that the rules for squares give methods for calculating the defect value, and the permissible defect value is fixed for each grade. In the case of teak conversions, the rules indicate only the size, location and number of defects that are permitted, and the defect value system of defects per 10 cubic feet or per ton of 50 cubic feet is not mentioned.
Scantlings are exported today as Special, First, and Second Quality. Special and Better Quality is the export quality for Teak Boards, Planks, Decks and Flitches. There is no standardisation of quality names with other countries exporting teak. For example, Special Quality is, at present, more popularly traded by Singapore, Hong Kong and Thailand as First European Quality (FEQ), and not Europe Intermediate as was previously called in this country.
It should be mentioned that in the case of small-sized scantlings, it is not practical to examine each piece as the lumber comes out of the mill. It is too time consuming as well as costly. The time for inspection is very limited. The integrity and the experience of the grader is the sole criteria in such cases. The rules can also be deceptive if followed too slavishly. Being a natural product, going by the book may sometimes result in instances where a piece of first quality is graded as special and vice versa.
Main Menu
Select Special
Must be free from the following defects :
Large knots , large beeholes , suncracks , large pitch or bark pocker , large chalk pocket , inbark , soft heart centre . sap , cross or sloping grain , shake , rough grain ( wild growth ) . splits , or serious mechanical injury , or excessively curly or wavy grain , unless otherwise specified .
In pieces which possess lengths pr widths not less than the average dimension of such parcel of timber . except pieces with lengths from 9' ( or the equivalent in metric system ) upward , which shall be recknot individually the following defects will be allowed : one knot ( 1.30 cm) in diameter , not penetrating to the other side , or one beehole ( 0.6 cm ) in diameter not penetrating to the other side and pieces carrying each of such defects should not exceed 5% of the total number of pieces in the parcel .
Special Market Specifications
These specifications intended for dimensions stock such as Decks and Margin pieces , shall have only one grade in each case .
General Requirement : These shall be well manufactured with cross sections rectangular throughout ; sawn full , thickness and width being 1/8" ( 0.30 cm ) full to the normal dimensions at the time of milling ; fairly straight grained , sound and free from injurious worm or beeholes splits . shakes , sapwood , large knots not exceeding 1,25" ( 3.80 cm ) diameter or unsound knots , corner knots , ingrown bark , wane , heart centres , or imperfections due to heart centre , excessive discoloration and rot , or other injurious defects , unless otherwise specified.
Decks : Upper face and the upper half of the calking edge shall be clear . One perfectly sound knot , but exceeding 1" ( 2.60 cm ) in diameter for every 10' ( 3 meter ) will be allowed . For decks of 10' ( 3 meter ) and longer up to 20' ( 6 meter ) two knots will be allowed provided that the distance between the knots is not less than one-third of the length of the piece . For decks longer than 20' ( 6 meter ) , three knots will be allowed , and the distance between each should be at least one - third of the length of the piece