A short review of finger joint method

Finger joint laminated is one way of joining wood with a shape resembling fingers when joined. This finger joint method in construction is very popular in the wood industry, especially for industry targeted for middle to upper class producers. The reason is because the nature of this joint is stable on small-sized wood. This is different from the pen and hole joints or hooked tongue. The finger joint itself has the same basic principle as the serrated joint.

Joint is the weakest part in a wood construction, that’s why many failures or damage to the structure are caused by the failure of the joint. Therefore, the jointing technique plays a very important role in obtaining a good structure. This study reviews the finger joint method, which is the strongest joint, because it has a stepped inclined joint surface. The inclined grain plane surface can adhere better, so it has greater strength than the vertical joint which has an ‘end grain surface’ that cannot adhere well. With various levels of slope comparison, and its effect on the flexural strength and modulus of elasticity of wood, below are the results of this study.
The flexural strength test of wood with finger joints ratios of 1: 2, 1: 4, 1: 6 and 1: 8 are respectively as follows : 115,541 kg / cm2, 151,014 kg / cm2, 282,791 kg / cm2 and 537,268 kg / cm2. And the magnitude of the modulus of elasticity are respectively as follows: 78.122 kg/cm2, 79.257 kg/cm2, 80.333 kg/cm2 and 100.654 kg/cm2.
From the results of the study it was concluded that the flexural strength and modulus of elasticity increased along with the increasing length of the connection, because the greater the ratio of the length of the connection made will result in an increase in the area of gluing. The 1:8 finger connection can be a better alternative compared to 1:2 finger connection and 1:4 finger connection.

Finger joint laminated (FJL) board is a solid wood board made by connecting pieces of wood using special glue into a board sheet with strong and stable joint quality. PT Karunia Jayama Sentra adopts German technology, using special machines to make more precise joints.

FJL is widely applied as a backing material for wooden floors, wall panels, ceilings and solid panel contents and many more. From the research results, we arrange the pieces of wood that will be used as FJL according to their respective quality and grade. This finger joint method is used to facilitate the production process of FJL.