The 52 feet ( 15 @.@ 85 m ) long stocks were made from Douglas fir . All timber had been pressure treated with preservative and well seasoned . It was estimated that a laminated stock would be up to 20 % stronger than a similar stock of solid timber . The timber used was 1 1 ⁄ 2 inches ( 38 mm ) thick and nine laminations were required at the centre , where the stock passes through the poll end of the windshaft . Careful attention was paid to where individual joints occurred between different pieces of timber . Both stocks were made during the work @-@ in , with one of them being trimmed and finished ready for use . The stocks were the first laminated stocks made by amateurs .