I have tuned skis for 8 years now by hand the old fashion way and we do use a wintersteiger to base bevel
1.) use a belt grinder to achieve a 1 degree all throughout the ski on the edges ONLY. this step is important because the base bevel will shave off a millimeter of base, therefore edge also if you dont bevel the edges first. if the belt is worn nicely, you can run the ski flat and rid of any edges that are higher than the base, therefore making it a zero bevel in regards to both the edge and the base. this will give you an idea on the structure of the ski whether its poor quality or good. Then proceed to working the edges to a 1 degree. this takes skill and practice..
2.) On the belt grinder, then bevel the side bevel. This process involves knowing what the side bevel of the brand of ski is. atomic is a 3 degree side bevel, K2 and most others are 2 degree.
3.) Put the ski in a vice and use a base bevel file and bevel the tips and tails with moderate pressure to achieve a 3 degree base bevel on the edges, then gradually to a 2 degree, one degree, then no filing at all underfoot. use a felt tipped marker and color in the base edge to see how well you are beveling the base edge. underftoo is the tip of binding to heel of binding. The underfoot area of the ski should not be touched by a ski file, it has already been bevelled sufficiently from the belt grinder.
4.) if tuning a race ski, take a side bevel tool with a new file and side bevel by hand. this is much more precise than with a side bevel of a belt sander. make sure you are using the right side bevel for the specific ski. After that, use a gummy stone and lightly swipe the edge to remove burs.
5.) depending on if you are racing or recreational, set the stone pattern in the wintersteiger. Stone grind the ski and vuala! If you experience any sparking underfoot, that is ok. You shouldnt have any sparking on the tips or tails. An experienced tech knows that sparking is a normalcy. it also means that you achieved perfect zero bevel with the edge and base= perfectly tuned ski.
- hopefully I was of help.