A good place to start for a bench is a sawhorse.  These are nice as you can walk 360 degrees around them, and by trimming the legs down, you can operate on your skis at waist level, and thus apply more file/scraper pressure.  The basic set-up shown below is a wooden sawhorse with secondary chunks of 2 x 4″ pieces of wood screwed on top, then the vises mounted to that.  A bonus of the sawhorse bench is that it is also easy to clean up afterwards and it can be stored out of the way.

A good ski vise can be the most expensive part of a tuning kit, but they are essential, especially with rounded, shapey cap skis which are tricky to hold. 

Use blocks to help support the tips and tails.  If you have the technology (a saw), cut slots in the support blocks so you can plug your skis in sideways and work on the edges without having to clamp/unclamp them.  Close enough is good enough.

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