It is never recommended to leave your edges factory-tuned, it does not only make the skis very slow, but it also might cause you break your ass. It is rather highly recommended to sharp them up a little bit. That is done with files and a diamond sharpening stone. To use these, you need a Base Bevel File Guide, which you attach the files/stones to. Directly after sanding or grinding, as the filing process is called, you may notice that your ski or board will be fairly slow. That is very normal, however as you ride the speed will quickly increase.
The great thing with a diamond sharpening stone compared to a file is that the diamond sharpening stone sharpen very quick and easy. There are three different types of files and diamond stones. One type of file are primary used for cutting, another one for maintaining sharpness and a final one which you use to find adjust, sharp and polish your ski or board.
What Diamond Sharpening stone to buy?
As buying files and diamond stones I would recommend a complete set called Base Side SKS Multi Tool seen in the picture to the left. It comes delivered with three diamond stones, a file guide and also a base side bevel file, so it features everything that you will need. The filing process described above can be all done with this kit. As I mentioned, you will get three diamond stones. One black colored which are used for cutting, a blue one to maintain the sharpness as well as a red diamond sharpening stone which you use to fine polish and sharpen.
If you however already got some of these parts, and so only wish to purchase single products, let me first start with a base side. An all-round one is SKS Base-Side Bevel File Guide which also includes one file. There are specified tuning tools for clamping only one diamond sharpening stone, the best affordable one is DMT ABG Aligner. Of course there are also the reverse, specified holders for multiple files. For instance one which is produced by the well-known brand Swix and is called Swix Adjustable Base Edge File Holder. It is made for files, but can also handle a diamond sharpening stones.
As for diamond stones I would recommend the three diamond sharpening stone package DMT Diamond W7EFC or a single four inch (10 cm) stone called DMT Diamond A4EE. Going for these files, you will get a few different sizes to choose between. An eight inch (20 cm) file called Viiala Chrome File is a great one or also six inch file in the name of Vallorbe Swiss 600-Grit Fine.