How I lubed and adjusted my Chinese-made Shule (German) brand version of the Marcato Marga 3-roller hand-cranked grain mill.
No guarantees here. This blog is about my particular machine, my experience and observations.
I checked the Marcato Marga site, and externally it is identical to mine except for cosmetic differences. Be aware that the interior could be very different.
On this other person's blog page: https://seedforsecurity.com/blog/79
in the first photo, the Shule is the pink box on the left. And it's the mill featured in the 4th photo. Again, that page is not mine; I'm just using it as reference.
Here's the same mill at Amazon, where it goes by the name Norpro. It shows the two screws (2 on each side) that you need to remove to get to the gears. There is a set of gears on both sides. And you can see the hex nut bushing in this photo.
On mine, there was a rough spot, slight resistance of the gears, at a certain roller position, as if the gears were rubbing there. it happened every turn of the rollers, about about every 2 turns of the crank since there is not a 1:1 gearing.
You only need to remove the 4 screws, two from each side. Then gently pull on the big adjustment knob, and the _core rod only_ of that cylinder comes out with that side cover. Do not attempt to remove the knob from the side cover or core rod. Knob, side cover, and core rod (axle) stay together.
After removing the two screws per side, the other side cover, the one with the crank socket and the hex nut, can be pried off. Mine was held pretty tightly via friction after removing the two screws holding it to the inner side cover.
There are four stand-off rods with nuts holding the inner side covers together. Leave those alone.
There are four hex nuts holding the feet and the base to the two inner side covers. Leave those alone. I mistakenly removed them, thinking they held the outer side covers, but they are attached only to the inner side cover.
(You may need to _loosen_ the 4 small hex nuts holding the feet and base on, in order to remove the outer side covers. You may need to loosen those 4 hex nuts in order to re-install the outer side covers. Just remember to tighten them when finished. I have disassembled this incorrectly once, but have not disassembled it "correctly" yet.)
That hex nut on the side with the crank socket, is not threaded. It is a _bushing_ with an offset - meaning the hole is not centered with the outer diameter.
The offset bushing is part of the system that allows the knob to adjust the distance of that roller to the other top roller and keep them parallel.
The "clock position" of that hex nut matters! On mine, the thin edge, I'll call it the index position, needs to be at about 1:30, or 45 degrees clockwise from noon. Just for reference, I had the knob set to 1, but I don't know if that matters.
I mention this here because it is important: If this hex nut bushing gets out of alignment, meaning it's not in the correct clock position, then the rollers might not stay parallel as you adjust the knob, but the gears will _definitely_ NOT mesh correctly. I learned this by trial and error upon re-assembly.
In fact, upon reassembly, I turned the hand crank and "felt" for the smoothness of the gears, as I used a wrench to rotate the hex nut bushing. Adjust - test - adjust - test, until you find the sweet spot for the clock position of the hex nut bushing.
I am not guaranteeing the correct clock position of your hex nut. So observe and record what clock position its "thin side" is at before disassembly. In fact, you do not need to remove it. I thought it was threaded, and needed to be removed. But it is held in place in the outer cover by friction only.
If your gears are not meshing properly, your hex nut bushing may already be out of adjustment.
Never force the crank. If very gentle pressure doesn't turn it (without grain, that is) then something is out of alignment.
This system of a cam shaft type of axle and the offset bushing allows the gears to be properly spaced regardless of which position the knob and roller are in.
Mine has been used for 4 years or so, and lots of flour was absorbed in some grease. I read somewhere to use peteoleum jelly to lube it, so I added that to the gears with two toothpicks held together.
You are also supposed to add a little oil between the rollers and the inside cover.
I got smudges of grease on the rollers, and wiped them off with a paper towel. I will also clean with isopropyl alcohol on a paper towel. And I will mill and discard some white rice and some wheat to further clean.
After the clean, lubricate, re-assembly, and adjusting the hex nut bushing, the rollers and gears turned smoothly, and the rough spot in the gearing (ie, resistance at a certain roller position) was no longer there.
On mine, the 4 side screws are phillips (cross), and the hex nut is 10 mm.
As you re-attach each side cover (two screws per side), only _loosely_ affix the first screw (that is, do not tighten it all the way) in order to allow wiggle room for getting the second screw aligned and started. If you tighten the first screw all at once, the second screw most likely will not align.
The outer side covers have a tight, but imperfect, fit. So you may have to "finesse" them a bit before you insert and tighten the second screw.
Again, no guarantees. This is just my explanation of my perceived experience with my machine.