My father had a hand grain mill from Retsel (an Idaho company that makes high quality grain mills). And as many of you know, hand cranking a grain mill can take a lot of work to get enough flour to make anything with. In a survival situation, it is imperative that you have the ability to hand turn your grain mill, but during other times it is nice to just flip a switch.
Many years ago, my father had turned this grain mill into an electric one. The only problem was that the only motor he had available at the time was way too fast. In order to bring the rpm's down, he had to use numerous pulleys and belts. It ended up being too large to be practical.
We first tried to attach an electric drill into the grain mill where the handle had been. Although I had high hopes, this approach ultimately failed. It was just too fast to work correctly, and when we used a slower setting, it didn't have the power.
We ended up using an electric juicer. This works well for us, as we had two juicers between us.
The juicer still needed to have it's rpm's reduced however. In order to accomplish this we had to buy a large pulley and a small pulley as well as the belt. Many homesteads may have old pulleys laying around, or on old machinery that you could scavenge for this.
After attaching the large pulley to the grain mill (in place of the handle), we attached the smaller one to the juicer. The grain mill was attached to a piece of plywood and the juicer was strapped down (see photo). We strapped the juicer down this way so we could keep the belt tight enough and still allow us to use the juicer for it's original purpose if we needed to. We strapped it down with an NRS river strap, which are one of the greatest tools to have around. They can do anything from holding gates shut to strapping stuff to your trailer or even holding a juicer down.
Once the pulleys were in place and everything was attached down, we had to fix a few problems. The first was that we now couldn't fit the hopper onto the top of the mill. The large pulley was in the way. This was easily remedied by adding a piece of plastic pipe to raise the hopper. We then added a large piece of cardboard to protect our hands from the pulleys and belt while they were spinning. And finally a folded piece of thick paper was added to funnel the flour a little better into a container.
There you have it. Now we have an electric grain mill that can also be used manually in case of emergency or long term power outages.