It's essentially the reverse of disassembly. But I will document it for clarity sake. I am assuming we're starting from a completely disassembled state. We will also cover the very-much mysterious 'alignment' process.(Step 1) Shaft assembly
If you have removed the burr-key & spring from the shaft, place the spring back onto the shaft. Push to compress the spring enough so that you can slip the burr-key in. Once that's done, allow the spring to relax. The spring will go around and wrap over the burr-key.
Put one of the two ceramic bearings back onto the shaft. Push it all the way in so it is positioned in the center of the shaft. The bearings are not directional (AFAIK) so it doesn't matter which way it goes in.
Put the shaft back into the grinder body from the bottom. Be careful to not scratch the grinder body (aluminium) with the shaft (stainless steel). The ceramic bearing should get wedged into the slot.(Step 2) Top ceramic bearing
Now, with the grinder placed on its side, place and push the top ceramic bearing in. The top bearing may not go in all the way smoothly. Worry not. That is intended as the bearing tolerance is critical and it's machined to a tight fit. As long as you get the ceramic bearing partially in, that's good enough for now.
With the top bearing partially in, put the top cap on. Remember it's reverse-threaded so turn it counter clockwise to screw in (while stabilizing the shaft). Alternatively, hold the cap steady and turn the shaft instead as necessary to aid screwing on the cap.
Refer to the video after step 3 if unsure.
Once the cap is partially threaded in, you can place the grinder upright again. At this point, you might notice the shaft can be a little wobbly.(Step 3) Tightening the top cap
Now, insert the two-prong tool into the slots and mount the crank. With your left thumb holding the prong-tool from moving, turn the crank clockwise as if you're grinding beans. This will tighten the top cap and push the ceramic bearing in fully.
To fully tighten the top cap, reseat the crank so that it forms a 45 degree again (similar to disassembly). But this time, the prong-tool should be at the bottom instead.
With your thumb, pinch the two-prong tool so that the tool gets closer to the crank arm. It should be slightly more than finger tight. Repeat and remount the crank as required.
As for the tightness, push with your thumb until your thumb feels a little pain as pushed back by the resistance. That should be the right tightness. Without a torque meter, I can only describe it as -a little more than finger tight, until the tool won't move further.
To check if it's tightened properly, remove the crank and the two-prong tool. Now try turning the shaft with only your fingers
. It should feel kinda tight and you actually need some force to turn the shaft. If the shaft turns easily with no resistance, repeat the step above to tighten the cap a bit more. It's better to do it gradually, than trying to force it too much at a time. If it's tighten properly, you can push the shaft laterally/horizontally and there is no play/movement.
Once you got to the point where it takes some finger-strength to turn the shaft, now put the crank on and try turning. It should move easily with one finger and no resistance at all.In case you did not follow the entire disassembly/assembly sequence. Do take note that you need to tighten the top cap (with the inner/outer burrs gap wide open, and not locked or at zero), Otherwise, your top cap may not be tightened properly.(Step 4) Outer burr
Now, invert the grinder body upside down and place it on top of the catch cup again.
Place the outer burr into the slot. Take note of the burr orientation. The big teeth should face downwards (with the grinder upside down). You will note that one side of the burr is grounded flat. That should point to the slot for the burr stopper.
Now, insert the burr stopper.
Note that the outer burr is slightly smaller than the slot and there is some play. This is expected. It's done that way so that the outer burr can be replaceable by the end user without specialized tool. The play will be taken up once the clamp ring is on, and the burr stopper will prevent the outer burr from moving further.
Place the clamp ring & screws. Tighten the screws initially with the short handle technique. Just loose finger tightness is fine, as we actually want the outer burr to be loose (so we can align it later).(Step 5) inner burr
With the grinder body still upside down on the grind cup, put the inner burr cone onto the shaft. Take note of the burr-key slot and try to fit into the key on the shaft. Once you manage to seat the inner burr onto the shaft, push the inner burr with your thumbs
. The inner burr should spring back without catching. Now, put the adjustment knob back on and tighten it.
You may turn the grinder upright again. (Step 6) Aligning/centering the inner & outer burrs
Put the hand crank on, and tighten the adjustment knob all the way in until the burrs lock (finger tight only). Recall that we did not tighten the clamp ring fully, so the outer burr can still move slightly.
Once the burrs are locking to each other, they will be centered to each other naturally. It doesn't take much to center the burrs at all, and is usually right on the first attempt. If you don't feel they are fully centered (visually), coarsen the adjustment knob by 0.5 dot and turn the crank by 1 revolution. Then, lock the burrs again.
Next, with the burrs locked to each other, tighten the three screws on the clamp ring to fix the outer burr. This time, you want the screws to be tight, so use the long handle technique. Again, the important thing here is never let the allen key slips (risk rounding your screws) by fully inserting the allen key before applying any force.
Another tips here is not to tighten any single screw fully in one-go. But rather, try to tighten all three screws gradually
. ie. tighten screw 1 with 50% force, move on to screw 2 with 50% force, move on to screw 3 with 50% force, then move to screw 1 again, with 70% force, next to screw 2 with 70% force etc etc...you get the idea. Keep going for a few circles until you feel like you can't tighten any more with reasonable finger-strength.
Once the screws are fairly tight, adjust the grind setting coarser by one revolution. So the burrs are not locking now.
Tighten the screws in circle again. This is to ensure the outer burr are indeed clamped fully. Again, a bit more than finger tight is the key (we have the leverage from the long handle). Don't go gorilla strength (some of us are strong!) because the screws can be delicate. Try to tighten all the three screws with as even force/torque as you can manage.(Step 7) Check alignment status
Now, to check your alignment.
First thing first, check for any mechanical/burrs wobble. Adjust the burrs to about 12 dots/1 revolution from zero. Turn the crank. Does the burrs wobble, and does the burr gap change as you spin the crank? They should not wobble and there should be no burr gap fluctuation.
Next, remove the crank. Apply lateral force to the shaft top, with your finger. Does the shaft move and is there any play? Next, push the adjustment knob at the bottom laterally. Does it move? Again, the answer to all the questions should be no. If the shaft wobbles, check if your top bearing cap is tight. If that's tight and still wobbles, redo the disassembly/assembly process and check for surface cleanliness.
Next, we shall check whether the burrs are centered to each other (within reason). First, tighten the adjustment knob so that the burrs lock again. That is your zero point. Now move the setting coarser by 10 dots, and then immediately finer by 3 dots. You should be at 7 dots away from zero. Turn the crank. If there is no burr rub, you're good to go. The lower the setting before it rubs, the better. But 7 dots indicate it's good enough.
Note: the reason we overshoot to 10 dots before backing up to 7 dots, is because of how a spring works. The spring is more accurate at setting distance when allowed to relax and then compressed, rather then going the other way round.
The alignment, once done, should be good until you remove the outer burr the next time. In regular use, you should never have to remove the outer burr, not even for regular cleaning. The only exception when you need to remove the outer burr is when you're swapping burrs. So you never have to align the grinder again once set initially.
There you go, that's the end of the assembly process![Cleaning]
For regular cleaning, you can either dry-wipe the grind cup with some paper towel, or to wet-wash. Either works. The grind cup is the only part you need to clean most frequently because it's in contact with ground coffee.
The bottom of the grinder can be cleaned with a brush & paper towel - don't wash/rinse with water.
If you want to clean the burrs thoroughly, just loosen the dial face all the way (use the trick in the video above for inner burr removal). Once the inner burr is out, you can use a toothbrush to brush both the inner and outer burr surface. There's no need to remove outer burr, nor there is a need for messing with the top bearing cap. Leave them alone.
As to cleaning frequency, there's no strict rule to follow - because Helor 101 has so little grind retention, there is almost no stale coffee retained in the grinder that will foul the grinder, unlike a conventional grinder (which most people don't even bother cleaning!). Technically, if you never clean the grinder, you will still be OK. I like to do the cleaning whenever I feel like it (every month or so) but I don't follow a strict schedule, and I don't notice any difference after cleaning (which means the grinder is OK to begin with).
If you insist, here's what I would recommend:
grind cup & bottom of the grinder (the adjustment knob area): weekly
grinder body & burrs : Every 1-3 months