Cutting the C blocks

1. First, take a sharp chisel and remove all the wood about 3 mm beyond the projected tips of the corners. See the red dashed lines in Fig. 1 for the approximate position of the cuts.
   
2. Using a suitable gouge, start paring away the wood on the upper and lower corner blocks where the C ribs will be, see the contours in red, "a, b, c, d", in Fig. 1. As in the image, naturally extend the curvature past the tip of the cornerblock.

   Make sure the bottom of the block you are working on is resting securely on your workbench and that the only pressure applied is to the block itself, otherwise the block might snap off as it is only lightly glued.

   Make frequent checks of the lines on the other side of the blocks to make sure you`re not undercutting.

   Also, with the help of a small square, keep checking everything is perfectly perpendicular.
   

3. Finish with sanding paper on a stick of suitable diameter, making sure that the point where the blocks meets the mould make a transition as smooth as possible. Run your finger over it to check for smoothness.
   
4. Check the contour again by realigning the template with the mould.