Renovating an LSM coffee grinder

Renovating a La San Marco commercial coffee grinder, by "Joey"

Step 1

I got a La San Marco grinder (which has Mazzer burrs inside) on eBay for 75 €. It had been used in a sports club and was very dirty. Unfortunately I forgot to take a picture of the dirty burrs. The coffee was packed solid and covered the three metal arms which are positioned around the burrs to sweep the ground coffee out through the hole into the doser.

So, after removing the hopper, I unscrewed the huge metal ring with the scale on it. On the bottom side of this you will find the upper burr. That's easy to clean. Watch the slits around it - you might find some fossilised coffee in them!

Hint 1: When you take out the lower burr - mark one of the 3 arms AND the 2 burr edges parallel to it with a water resistant pen to find the exact position again!!!! When cleaning it, take care not to scrub the marks off! If you don't position the burr at exactly the same position again, the two burrs will "bite each other" when the grinder is reassembled and you adjust for a finer grind.

Step 2

Next - take off the doser. You can't imagine how much coffee you will find in there! For the LSM I used several Allen keys and one Philips screwdriver. Start with taking off the electrical shut-off switch on top of the doser. Then comes the transparent plastic part. Before you can take that off, unscrew the handle in the middle of the doser (a huge spring will pop out, but it's self explanatory how this fits so don't worry).

As the electric off-switch is soldered on and I didn't want to open that, I couldn't get it off the transparent plastic, so I just let it stay there. In the picture you can see it on top, still connected with the grey cable. After removing all that, the doser retaining screws are easily removed (see the picture on the right).

After cleaning everything you might not remember where things should go, so here is a photograph to help:

• The position of that double-ended spring that belongs in the middle of the doser base is marked by the yellow line
• The dosing lever should be in the furthest possible clockwise position (blue arrow)
• The arm which activates the dosing counter should be parallel to the spring end (green line).This arm is moved by the little black "nose" to the left of it in the photograph.

Step 3

There is a pin that has to be retracted locked in place by the main body of the doser handle.

If you don't put it in this retracted, clamped position. the spike will lie stretched and loose under the handle (yellow circle).

Step 4

As there is nothing to hold that little spring in position while putting the black plastic lid on top of that doser part again, hold it against the lid instead. There is a raised "dimple" to hold it in place - press the spring against it (yellow arrow).

But it gets worse: The grip you see in the picture - well in fact you have to hold that lid from the other side! The side you see now will be "inside"-looking down.

Therefore you use the hole in the lid and poke your left forefinger through it, holding the spring from the outside (one end pressed against that dimple).

While positioning the lid on the doser base again, you also have to hold the doser handle in the furthest clockwise position (use your remaining little finger from the left hand to hold it) ... and you have to watch out that the spike remains locked and the counter arm stays in position, too (this is using your right hand). Now this was the trickiest part. It might sound weird, but once you see it - you'll know what I mean.

Conclusion

Congratulations, if you manage to put all parts in their place again, it should look like on the picture on the right.

Now I was asking myself - "Is it really necessary to explain how to disassemble a grinder? Who does that?"

I hope lots of you do it depending on how often you use yours. All I can say is - what I saw in that grinder - phew, I'm happy I didn't drink the coffee that guy offered me when I picked that baby up.

So don't only clean your espresso machines, take care of your grinders, too.