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 materia
l. 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.
Bar and feeler gauge.
Ray's Way flattener.
Hand Stone and tool.
Edge is nice and black before filing.
File guide and file.
The marque of Blind Speed.