The stair components are sanded several times until the finished surface is obtained.
The first sanding process is the sanding of the wood surface from all sides in preparation for painting, i.e. wood sanding. The subsequent varnishing process usually involves several applications. Each layer of lacquer must be sanded again before a new coat of lacquer is applied. This intermediate sanding improves the adhesion between the layers of varnish.
The sanding is done in several steps. The first is usually sanding the narrow sides. Special edge sanding machines are available for this. CNC machining centres can also sand the freshly produced outer edge after milling the contour. Then the top and bottom sides are sanded on a wide belt sanding machine. In smaller companies you can alternatively also find long belt sanding machines.
The edges of the steps and stringers are usually rounded or chamfered. This transition area between surface and narrow side sometimes requires a further sanding operation by hand or with an orbital sander.
