Here's my experiences with a coffee grinder. I have a commercial coffee grinder that (up until my last brew) was the only "mill" I had ever used for my brewing grains. It doesn't look like yours, however, but more like the ones you see at the supermarket to grind your coffee - boxy with a big hopper on the top.
The mill itself is much more aggressive than a corona mill type setup. Even though it is fully adjustable, it does not provide nearly as consistent a grind as does the corona. It shreds the grains as opposed to crush. I found I got more flour, a lot more shredded husks, and a lot more uncracked grains.
I have had a corona gathering dust for years, but never used it, as I had the coffee grinder. I finally motorized the corona and used it for my last batch. My efficiency went from 65% to 72%. The mill was the only change in procedure. Also, I should state that my efficiency had been dead on 65% for years and many batches.
That said: the coffee grinder gets the job done....and QUICK!!! (Another reason why I was loathe to stop using it - with 60 Lbs of grain needed for one batch....) I never had a stuck sparge with it. The other advantage is it's a LOT less messy.
I had thought about grinding down the teeth on the coffee grinder to see if it would improve the results, but now I think I am gonna stick with the Corona as I am very pleased with its performance and the efficiency increase.
Just my experience - YMMV! Cheers!
