Evaluation of the effect of optimal fit criteria on the compressive strength of open mortise and tenon corner joints

Abstract

AbstractThe study examines the degree of deviation from the nominal size of the produced open full-width mortise and tenon joint elements for their optimal pairing based on the measured thickness and gap width data. The characteristics of the measuring devices used were analysed by the repeatability and reproducibility test. The compressive strength of the single-glued joints (where only the surfaces of the tenon were glued) and double-glued joints (where the surfaces of both the mortise and tenon elements were glued) for various joint fit categories was also determined. It was found that despite the huge number of produced test specimens and their measurements, the joint fits could be maintained with the milling machine and tools. The thickness of the joint could be characterized by measuring the data at the centre of the tenon, whereas the gap width of the mortise could be characterized by measuring the data on the side of the tool leaving the wood. The double-glued joints showed higher breaking force and displacement values as compared to the single-glued joints. The joints were found to be the strongest at a tight fit of 0.1 mm.