This paper presents the most common traditional dovetail joints used in furniture making in past centuries, which are among the almost forgotten skills, practiced today by only a relatively small number of restoration workshops. The paper deals with the basic joints used in the restoration of furniture and traditional woodworking (houses, churches, temples, etc.) for the purpose of protecting rich cultural heritage. The history of furniture making is also the history of the art of making joints. In restoration, knowledge of these joints facilitates and accelerates the dating of furniture pieces to be restored. For this reason, the aim of this paper is to present an overview of the use of dovetail joints. The decorative effect of these joints and their constructive ingenuity certainly deserve more attention and research. A historical review of the development of traditional dovetail corner joints demonstrates the importance of the skill of crafting joints that stand the test of time and survive to this day. With the development of art, the joints became more and more decorative, but also of higher quality to withstand the various stresses that occur when furniture is used. Practical examples of making traditional dovetail corner joints are used to show how important it is to preserve the craftsmanship of these traditional joints from being forgotten, which is necessary when restoring furniture and other historical structural components made of wood such as ceilings, floors and altars.

This paper explores the possibility of using recycled seashells from marine coasts of the Mali Ston Bay in Dubrovnik-Neretva County, Croatia, to create a novel bio material derived from waste seashells. In this research, two types of waste seashells, mussel (Mytilus galloprovincialis) and oyster (Ostrea edulis), combined with natural, non-toxic binders (bone glue) were investigated experimentally. The goal is to develop a sustainable material, suitable for the production of furniture and decorative objects. The parameters studied, included physical and mechanical properties of this material. The results showed that this bio composite material, derived from recycled seashells, is hygroscopic and has low compression strength. It should be used for making furniture components that don't bear heavy loads and it is suitable only for interior applications. This study presents an eco-friendly and sustainable material option, while optimizing the recycling of food waste materials.

• This paper investigated the withdrawal capacity of the double-threaded nuts mounted in 3D-printed materials. The basic technical properties and the withdrawal force of the double-threaded nuts for the specimens made of PLA, WPLA, and layered WPLA+PLA configuration (with and without STP adhesive) were investigated. The results are compared with the literature data of withdrawal force for beech wood, MDF, and par-ticleboard with and without the adhesive. The research has determined the effects of the properties of 3D printed materials (density, compressive and tensile strength), the infill and printing patterns, and adhesive on withdrawal capacity of double-threaded nuts. Double-threaded nuts mounted with adhesive had higher withdrawal forces (about 25 % for PLA and WPLA specimens, and 15 % for layered WPLA+PLA specimens) than those mounted without adhesive. The highest values of withdrawal forces, regardless of the adhesive, were obtained for layered WPLA+PLA configuration, followed by WPLA, and the lowest for PLA. No significant difference was found be-tween the withdrawal forces for WPLA and layered WPLA+PLA specimens for both cases – with and without an adhesive. The withdrawal forces of double-threaded nuts for the PLA specimens were higher than the withdrawal forces for the beech (16.7 % mounted without adhesive and 11.6 % mounted with an adhesive), and other combinations showed a difference higher than 35 % in favor of 3D printed materials. The present analysis, which determines and compares used traditional dismountable connectors in 3D-printed furniture elements, is applicable for research and practice.