How I make my vinegar bottle slides.  I clamp 2 pieces of 2x4 to a table at a right angle and another chunk of wood to support the neck.  I put the bottom of the bottle in the right angle and turn it with my left hand while holding a glass cutter against the neck with my right hand.  I make one score around the neck.  I use a piece of blue painter tape around the neck as a guide to keep my score straight.  Then I pour boiling water over just the score while turning the bottle and then stick it into a can of water and ice.  I repeat this 2 or 3 times until the end falls off the neck.  Then I measure for the length of the slide and repeat the whole procedure.  To finish it I use little (4" x 4") stress of wet-dry sand paper on a small flat piece of wood and grind the end of the slide on that.  Keep it very wet.  I start with 60 to 150 grit, whatever I have on hand to take out all the imperfections and to slightly round the edges inside and out.  I then move to 400 grit and then 600.  The sanding takes 1 to 3 hours depending on how good the break was.  I usually do this while watching TV or chatting with a friend and the sanding is a fairly mindless and boring task.