Mount ski in the vice with the base vertical & facing away from you. Secure the tip & the tail in the lateral vices. Put masking tape down the sidewall of the skis to keep the filings & stone dust out of the bindings.
It is essential to first stone down any side edge damage with a alu-oxide stone as the impacts with rocks etc case hardens the edge so that a file can’t touch it. The alu-oxide stone is best used with a side edge angle guide but with a bit of practise can be used freehand.
Using a side edge angle guide, file (if required), stone & polish the side angle until you can feel a that a slight burr has been raised over the base edge (known as the 'hanging burr'). After initial angle setting & polishing etc, then the edges can be kept in tune by regular (daily in icey conditions) use of medium & fine diamond stones.
A note regarding the use of PVC base tape which a number of companies (well actually the people who make the tape) tout as being required to prevent swarf damaging the base when doing side edge tuning & is shown on the SVST tuning video. I don't use it for a number reasons:- it's a real pain to apply smoothly.
- it either peels off when it shouldn't or is so sticky it leaves a residue on the base.
- when filing any swarf is released over the top sheet side of the ski away from the base so just mask out the bindings & use a paint brush to clear off the bits.
- I'm concerned about the thickness of the tape altering the angle of the side angle guide, especially if it’s creased.
- it's expensive!