Carving oak panels for the strycsitten

The panels and the supporting 'triangles' for the horizontal rails are the most complicated parts of the strycsitten as they are ornamented on both sides. They were made of  European oak. I used a combination of modern machinery (drill press, router) and traditional hand tools (gouges, chisels and chip knife) to make the  four panels and eight supporting triangles.

Panels

The panel were made of simple oak planks slightly smaller (3-4 mm) than the grooved frame they  had to be inserted in, allowing for shrinking and swelling of the wood. Below the decoration plan of the panels is shown (left). On the other side (right) an alternative plan I considered but did not use is shown.

A pine panel to test the thickness of the chamfered edges and the depth of the lowered parts.

I started drilling the holes using a drill press with Forstner bits. This allowed for an exact and smooth cut. After that the 'windows' were rougly cut out using a jigsaw. I continued  making the 'windows' identical using a jig with a router. After that another jig and router was used to lower the circle with the three drilled holes. I carved the rest of the panel using traditional hand tools, such as gouges, chisels, ground plane and chip knife. The rounded corners of the window were made sharp with a chisel.

The jig used for routing the windows. The panel was slid in (arrow 1) and secured by a wooden stick (arrow 2). 

After the first window was routed, the panel was inserted again upside down to rout the second window.

The router jig used for lowering parts of the panel. 

The lines were used to align the jig to the correct place on the panel.

A pine panel used to test the router jigs. You can see the rounded edges in the window corners.

Two of the four oak panels. The other sides of the panels are identical.

The panels were finished with three layers of linseed oil before construction of the strycsitten.

Supporting triangles 

The supporting triangles were made of oak planks with the grain diagonal to the squared part. This was done to provide more strength to the protruding point between the two arcs. All triangles needed to be exactly 15 cm long as they had to fit perfectly into the grooves of the rails. I planned to use no dowels or glue for the triangles. The decoration plan  for the supporting triangle is shown below; the lowered part is shown in light grey.

The side with the two arcs was cut using a jigsaw and sanded to the correct lines with a large belt sander. Also here I first drilled the three holes using a Forstner bit in a drill press, before lowering most of the part with a jig and router. The remaining edges were lowered using a chip knife, chisels and gouges. Hand tools were used as well for chamfering the edges. The triangles were finished with three layers of linseed oil before they were using in the construction of the strycsitten. 

Router jig for lowering part of the supporting triangle. The triangle was inserted in (arrow 1) 

and secured by a wooden stick (arrow 2). The other side of the triangle was done the same way.

A finished oak supporting triangle in the strycsitten. Note the diagonal grain of the wood.