Virtually every ski today comes from the factory with a high quality stone grind, and often the base edge is “relieved” from the base material. This is a description for a factory process where the base steel is made roughly parallel to the base material, but set very slightly below the level of the plastic. When you, your coach, or your favorite shop inspect the factory base bevel, be sure to determine if the base side steel is actually angled (and how much) or if it is relieved.
One way to check your base bevel is to lay your true bar across the ski and carefully hold the bar flush against one base edge, testing in several spots along both edges of the ski. If you can lay the true bar flush against the steel, you have a base angle. Does the true bar just touch the corner of the steel & the base material? If so, you have base edge relief. Now examine the gap that is present on the other side of the true bar. Measure this gap in several places along the length of the ski. Ideally, it is consistent throughout the ski’s length. I like to see between 1-2 mm of consistent gap under the true bar – of course this is personal, and you need to test yourself to decide what is best. I also like to use an old gap dwelling tool or valve clearance guide to measure this distance (bonus points if you have one lying around!).
Many athletes will choose to start at one half degree and test from there. Remember, it is always easier to increase base bevel angle. Decreasing the angle requires extensive, precise, and very skilled stone grinding. Be sure to set every ski you own for that given discipline at the same angle, and check for consistency of angle throughout the season.
As far as the actual technique of applying the base bevel, just follow a few simple guidelines:
- Cleanliness is godliness – keep all the filings away from the ski using an inexpensive paintbrush.
- Always pull the file so that the filings are ejected away from the base material not into it. If you are right handed, that means the tip pointing towards your left and file the furthest edge, then flip the ski and place the tail towards your left and file the furthest edge away from you.
- Use the sharpest, smallest, straightest file you have. I ALWAYS check my files with a true bar before using them. Especially check the file for “tail”, which is when you have a nice straight file but the last centimeter or two veers off course. If this happens, don’t be afraid to break that section off. For base beveling, I like to use the finest file I can, and choose one that has very shallow tooth height. This yields a more precise cut and the file cuts less with each pass, allowing for more accuracy.
- Use only high quality files made specifically for ski tuning. The files from the corner hardware store definitely won’t do the job here.
- Watch carefully to ensure that file is not cutting the base material.
- Hold the file and file guide precisely. Press straight down, with gentle to moderate pressure (don’t bend the file). Let the sharp file do the work.
- Pull in long, smooth, overlapping strokes. Count your strokes so that you pull the same number at the tip, middle, and tail, on both sides, and on both skis. Brush the file & ski clean after each pull using your paintbrush.
- Polish the base steel with a hard Arkansas or ceramic type stone.