So this blog post started with some
Race Video of 1 of our Junior racers. I saw a funny "hitch" happen in their skiing when the heel was weighted. I have had the same thing happen to me- when the tail of the ski is railed- so I knew that
I must check the flatness of the skis in question. I checked the skis today and found them to be quite railed (also known as "edge-high," or "concave base") at the tail- and the flatness of the bases was inconsistent over the entire length of the ski.
So what does this
Inconsistent Flatness do to the tune? It pretty much ruins it. A ski cannot be properly beveled until it is flat- because the bevel tools rest on the base.
What does it feel like?
A concave ski is EXTREMELY unforgiving of fore-aft balance and edge angle mistakes, and it can even
CAUSE TECHNIQUE ERRORS because the ski will not behave properly.
So how do you
diagnose and correct flatness problems? Everything I did on this pair of skis is explained on other blog posts, but I will try to condense the process here. Look for pictures after the text.
1.) Determine flatness with a True Bar. I used a feeler gauge as an auxiliary tool in this case. I like using a feeler gauge along with a True Bar because it is a more objective way to measure how flat a base is- and how much work is required. I use a .001" feeler for this work. By experimentation, I have learned that I can feel as little as .0015" variation, so I try to get our skis (and the skis I work on) within .0005". That way, I KNOW they are great!
2.) "Zone" the ski. This means marking the ski into "Work Zones." When I find only part of a ski needs work, I mark that "zone" with wax. Then I work on the marked areas of the ski until the entire ski is uniform.
3.) Flatten the base/edge by removing material. I have found a Base Flattening File, Ray's Way Flattener, and Ski Visions Base Planer are an extremely effective combination of tools to do this work quickly.
4.) Repair Structure with a hand stone and/or sandpaper.
5.) Blend new structure into old with brushing/polishing.
6.) Blacken the edge.I have covered this topic previously, but I will show pictures again. It is VERY difficult to see how an edge is changing when you are working on it. Blackening the edge with a Sharpie is a big help.
6.) Bevel the base edge.
7.) Rip the side wall.
8.) Bevel the side edge.
9.) Tune/wax as usual.
10.) In my shop, a ski this good gets a sticker.
![](/Resources/Pictures/bar and feeler.jpg)
Bar and feeler gauge.
![](/Resources/Pictures/zoning.jpg)
Zoned ski.
![](/Resources/Pictures/flattening flie.jpg)
Flattening file.
![](/Resources/Pictures/flattener.jpg)
Ray's Way flattener.
![](/Resources/Pictures/planner.jpg)
Planer.
![](/Resources/Pictures/hand stone.jpg)
Hand Stone and tool.
![](/Resources/Pictures/back tail.jpg)
Edge is nice and black before filing.
![](/Resources/Pictures/b beveler.jpg)
File guide and file.
![](/Resources/Pictures/sticker.jpg)
The marque of Blind Speed.