Hi,
Just wanted to let you know that there is a box of already milled flax seed. It should be in your grocery store with all of the flours or baking isle.
I used to ground time and time again, but my grinder broke and I find much easier and still tastes great. I buy mine at Walmart for $1.27, not bad.
I think your coffee grinder should be fine, tests the waters so you know where it stands though.