Finger Jointers

Basic description of finger-jointing equipment. November 11, 2008

Reprinted with permission from MLS Machinery, Inc.

Finger jointers are used in order to recycle and reuse wasted wood. Basically these machines take the off cuts or strips of solid wood, move them through a shaper that has a specially designed cutter to produce fingers and then glue them together into long pieces. This allows these long pieces to be re-used for other applications; such as hollow door frame manufacturing, door frames that will be painted or veneered, window manufacturing, etc. There are numerous applications were finger jointed pieces of solid wood can be used specifically if these parts are not going to be visible or will be painted in the end product.

Do not confuse this process with the clamp carrier, a clamp carrier glues boards together in width only, finger jointing glues narrow strips together in length and butts end to end. Finger jointing works in the following way, a shaper with special cutters will produce little fingers in the ends of pieces of wood as discussed above, then glue will be applied into the fingers and the two pieces will be clamped together in a longitudinal form in a press that can be 16-30' long for a short period (the glue sets up very quickly). Once clamped, the pieces pass through a cut off saw so that they can be cut into the lengths desired.

When talking about the speed of these machines, the term "lugs per minute" will be used. The more lugs per minute, the more finished ends per minute both glued and shaped, the higher the production of the machine. The higher the production the more automated; faster machines will be self loading, aligning, have two shapers to do both ends of the piece almost simultaneously.

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