Step 2 Buy a "press" for squeezing the oil from the seeds.
Step 3 Decide if you want quantity or quality with regard to the oil. If you want to get the most oil out of the seeds, adding heat and sometimes a solvent can increase the amount of oil extracted from the seeds. If you want pure oil that's unaltered by heat or contaminated by solvents, avoid using heat or chemicals.
Step 4 Place the flax seeds in the press and crush the seeds to extract the oil. This process produces some amount of heat, so if you're doing this on a large scale and you only want "cold-pressed" oil, make sure you have plenty of ice cube supply. Filter the flaxseed oil, if necessary.
Shelf-life is short for flaxseeds omega-3 oil. So, keep it away from heat or light, and use it as fresh as possible. Why don't we see gallon size flaxseed oil in grocery? Simply put, shorter shelf-life and higher cost.
source - http://www.ehow.com/how_2315992_make-flaxseed-oil.html