Andrew Itzov

The photo does not picture the grooves well. First, both burrs have similar grooving. Note that grains are pushed against the counterclockwise side groove. For a groove at 12, o'clock this is to the left. It is perpendicular to the plane of the burr. The bottom is tilted. I cut it first. It is like a saw gullet and the other is the cutting face. Bought a 10x lighted magnifier with adjustable arms for mounting, from Amazon. I have worked on this project or a few years and believe most bugs are gone. Stone mill grooves are different. Wheatberries are rolled up the sloping groove bottom so the bran is flaked off in bigger pieces.

Thanks for your interest. Here are photos of the burrs.. Yesterday ground many pounds of flour at about 2 cups per minute.

I use a modified Victoria Mill. Using a diamond wheel on a 4 1/2 grinder to grind the burrs flat. and then few thousands concave, leavng  a one quarter inch wide perfectly flat area at the perimeter. Use Prussian Bluing, a flat reference plate and Dremel toll with 1" Wheel for this. Grind the grooves with the Dremel to make a sharp edge on the side of the groove where the grain is cut. There should be NO GROOVNG in this area.
Control grain flow from the hopper as follows. Make a five inch diameter disk from 1/4 inch
plywood. Cut a 3/4 in. hole at the center. From hardwood doweling, make a taper- 7/16 at the end increasing to 9/16 one half inch from the end. Suspend it with a threaded rod and crosspiece on top of the hopper. With the small end of the dowel at the top of the plywood, no grain should flow. If the small end is lowered to the bottom of the plywood, flow will be more than the grinder can process. Grain should flow only when the mill runs. I cut 1/2 inch deep slots at the top of the hopper. If the crosspiece sits in the slots grain can flow. When on top, it will not flow.
I use a 750 RPM drywall mud drill. You MUST use the side Handle for control. I insert a wooden mop handle and firmly support it. I believe the best way to fit the mill to the chuck is to grind a diameter that cleans up and fits the drill.
For this, Clamp the mill mouth side down to a bench. Grind a diameter about one inch long.
The drill can easily be overloaded.  A clamp on ammeter costs less than a drill.
Note where the main shaft meets the 1/2 ball. I smoothed a piece of a file and placed that side next to the ball.
This machine makes nice flour at a good rate, Bran is fine and cost is about $150. The burrs should be adjusted tight. The hard iron will not wear.

Here is a description of my modified Victoria mill:

I bought a Victoria Grain Mill from Amazon for about fifty dollars.
I ground the burrs flat from the outside diameter towards the center for one quarter inch.
This required shimming the stationary burr away from the body to maintain engagement at the shaft- rotating burr.
I ground sub-flush the rest of the burr working faces.
I cut grooves with a Dremel tool, one inch diameter diamond blade. The grooves follow from the existing ones in a CCW spiral to NEAR the OD. A few more were added to the existing 40. The walls of the “downstream”side of the grooves are ninety degrees to the surface. The depth shrinks to zero at the end of each groove. The spiral shape produces a large force outwards on the grain. The adjusting screw is tightened so the plates are pressed together with many pounds. The metal is probably white cast iron. It is very hard  and the burrs just shine.
The large outward force pushes flour particles across the “no clearance” zone where the grooves end.
I drive the machine with an old Milwaukee Electric Tool Hole Hawg. There is a three jaw coupling in the drive and a one half inch shaft installed in the main shaft. The main shaft was shortened where the crank normally attaches. The drill turns at 300 RPM at low setting and has a high torque. The modified grinder produces a heavy load. The project lasted a few months of “improving”.
The setup makes flour at a much higher rate than videos indicate for mills selling for a few hundred dollars. I run the typical two to three pound batch through a second time. It takes a couple of minutes and probably cuts the bran finer.
I have been using the King Arthur Classic Whole Wheat recipe, with honey and oil but not milk powder. (I did not have any).
It is delicious. Today’s batch is cooling. Never experienced a better aroma.
Andy