Several species of trees having a structural capacity were present in Egypt during the construction of the pyramids, the sycamore, the date palm, the doom palm and the Nile acacia; to those species are added imported species like Lebanon oak or cedar. According to current knowledge, the barks were sawn in logs, surbille or block for then being cut out in beams or boards. The weaker species, small sizes or inappropriate form could be used as cross-pieces for towing, levers or wedges.
The quantity of wood required as sleepers, rollers, sledges or lifting frames surely forced to square less parts as possible in order to maintain the structural value of those. A log from 100 to 200 mm in diameter loses 36% of its section after carpenters devoted hours to square it and produce chips requiring disposal; it is wasting time and resources. The sledges shoes could very well be round, they ended up being levelled or roughly square, a question of time, one had to swivel the parts to force them to become more or less square, usable for other so necessary ends. Moreover, can one really speak about sledge or simply about framework made of two shoes connected by two spacers, a bard?
Many contemporary representations of the transport or lifting devices show squared parts which seem assembled using nails or pins, whereas at the time, the Egyptians used much ropes, lashings and ligatures on wood logs, just like they did on beams for their boats.