MasterGitar.com MasterGitar.com

Cutting and gluing the fan struts and braces

Cutting and gluing the fan struts and braces


It is very important to cut the guitar fan struts and braces for strictly radially, i.e. along the fibers (or grain) of the wood. The direction of wood grain can be clearly seen in two planes. The third plane is not visible, but can be determined by simple splitting.

Cutting the fan struts and braces

Fan struts and braces should be cut radially. We will use the method of cutting with the saw where we can perfectly see how the wood grain is directed. Then we will split the wood to accurately determine the invisible direction of wood grain and then only, following the split direction, we will cut the wood completely. I believe this is the best way to avoid mistakes in terms of radial cut, besides it is the gentlest method towards the wood.

Initial blanks

That is how generally look the blanks for making fan struts and braces. It is convenient when their size is a bit larger, to have some space for variations, in case the cut is not perfectly radial from the beginning.

saw-brace1-680

One direction of the grain is clearly seen at the end. The second is along the fibers, which are clearly visible as lines in the next photo. We cut the corner. Then we level with the plane that surface along the grain of wood. There is no image for that, but the grain layer is clearly visible.

saw-brace2-680saw-brace3-680

After that, along this surface we begin to cut straight plates to make blanks for struts and braces. These plates will strictly follow two directions: the wood grain will be vertical and go exactly along the long narrow side.

saw-brace4-680

But there is the third direction that we have to find out by splitting. The image below shows everything. I demonstrate two parallel splits for clarity.

saw-brace5-680

Braces are, actually, ready. This split we level with the plane and, in respect to that surface, cut already radial blanks for strutting. In the second image below we can see the end-grain of this blank - I painted on with the pencil for greater clarity.

saw-brace6-680saw-brace7-680

 

Gluing the acoustic system of fan struts, braces and reinforcing plates

We have to determine our favorite acoustic system of fan struts and braces for the soundboard. Then make it, glue it and work out accordingly. At the end, we should coat all the inside of the soundboard with varnish, which greatly increases the reliability of the instrument when humidity changes. I do spray the inside of soundboard at very end, just before gluing the soundboard to the body, in order to determine clearly all borders, where it is not necessary to varnish.

I glue the fan struts in the shelf, and the braces with the help of rod clamps and flexible batten placed on the outside back surface.

I decided not to use reinforcing plates for gluing seams, but made one under the bridge. This is made from the same 2mm pine plate. I also made two additional half-braces for the back of a small height.

On the soundboard, at the area of upper end-block you see an element that after attaching the soundboard to the body will become a part of that end-block. There are two levels: the wood with grain across like for the reinforcing plate and little block of solid wood, which will become "L" shaped part of the end-block. Reinforcing plate is tapered, forming a “skirt”, which prevents cracking of the soundboard at the edge of the fingerboard.

glue-brace1glue-brace2glue-brace3glue-brace4

The video version of the lesson

Микола Руденко