Replacing burrs of Rancilio Rocky grinder

[BuzzedLightyear]

Anybody have a step by step guide for replacing burrs of a Rocky grinder? Thanks in advance.

[TimEggers]

Hi Buzz,

Yeah it's simple:

1) Remove hopper lid.

2) Remove the three screws which hold the finger guard in (these also hold the hopper on).

3) Lift hopper straight off of grinder. (You can remove the stop screw on the bottom of the hopper so that in the future you can simply depress the locking tab and unscrew the entire hopper to remove the top burr.)

4) Unscrew the top burr assembly (the large brass part). Turn it in the same direction that would make the grind coarser (clockwise I think, but I don't remember for sure).

5) Both burrs are held in by three slotted screws on each burr. Remove screws to remove burrs and replace. Clean machine as needed before reattaching the new burrs.

Follow the steps above backwards to reassemble.

To get the grinder back into the proper range with the unit unplugged turn the upper burr assembly (after you have the new burrs on) all the way down until it touches the bottom burr. Back it off a little (now align your hopper as best you can so the screws go back in so the numbers are close to the "0" on the dial. This will assure your burrs are close enough together to make the number relevant (like they were when the grinder was new). Once I put the hopper on but the burrs were too far apart and even at what used to be zero the grind was very coarse.

Replacing the burrs is very simple and should be no problem, good luck!

[Randy G.]

With a bit more detail, just in case someone needs it:

1- Unplug the grinder.

2- Remove hopper lid.

3- Look down into the bean hopper and remove the three screws which hold the finger guard in Place. Once removed the hopper can be lifted off the grinder.

4- For future benefit, remove long screw protruding from the bottom of the hopper. Wit that screw removed, in the future you can simply depress the locking tab and unscrew the entire hopper and top burr as a single assembly without the use of tools.

5- Look down into the grinder- that large brass part is the upper burr carrier. Unscrew it counter-clockwise and lift it out of the machine.

6- The upper burr is easy to remove. Unscrew the three retaining screws which hold it to the upper burr carrier. Using the proper size screwdriver is important. Lift the burr off the carrier and thoroughly clean the carrier and its threads so that there is NO coffee residue or oils left. The new burr must sit perfectly flat. Clean the screws the same way and torque them in place, working slowly in a circle to get them seated evenly as you go.

7- The lower burr is mounted to the carrier that is attached to the motor. This one is a little more difficult because it can turn in response to the torque applied to the screw. You can use a 1/4" drive "Tee" handle socket, a 6" extension, a 1/4" socket, with a hex screwdriver bit. You can even have someone else push down on the handle while you turn the handle.

8- Once the three screws have been removed the lower burr can be removed. One again, remove all traces of coffee residue in there, including the threads for the upper burr carrier. The new burr must fit perfectly against its mount. Tighten the three screws in the same was as mentioned above.

9- CAREFULLY screw the upper burr carrier back. If you place it flat into the bore, then carefully turn it counter-clockwise until you feel the first thread "click" into place, and then turn it clockwise it should start easily. DO NOT cross-thread! Screw it in until it stops then back off about .5". Align your hopper as best you can so the screws go back in so the numbers are somewhere close to the "0" on the dial. Be aware that it is possible that the new grind number may very well be different then the old grind number. It doesn't matter.

[Jarno]

With a bit more detail, just in case someone needs it:


4- For future benefit, remove long screw protruding from the bottom of the hopper. With that screw removed, in the future you can simply depress the locking tab and unscrew the entire hopper and top burr as a single assembly without the use of tools.

I think the purpose of that screw is to keep one from screwing the hopper to less than '0', thus keeping the burrs from grinding against each other.

[HB]

Really? It's been a long time since I used a Rocky, but a similar safety screw doesn't prevent the burrs from touching on Mazzers or Macaps. I believe its purpose is to limit the travel of the burr carrier if it binds on rocks or something, which otherwise could allow the motor to forcefully unscrew the burr carrier.

[edna713]

You are correct Dan. If that long screw is NOT there, and a user presses the adjustment unlock button with the motor running?

The entire top of the grinder will unscrew itself in about 1.6 seconds. (an approximate timing)

And, if I may, a suggestion for any brand new rocky owners: as you unpack it from the box, remove the top lid, invert the grinder and give it a good shake and a slap on the side.

Very occasionally, someone at the factory may throw in a spare loose screw for the burrs. If left in place, and the motor operated, it will instantly destroy the burr set. A bad thing!

d

[BuzzedLightyear]

Thanks for the tip guys!

I could not believe how simple it was! I wish restoring Hot Rod's where this simple.

I was disappointed in seeing how small the burrs where. However the burrs where long overdue for a change. My first shot was amazingly good and made me realize I need to make sure I replace them every 75 pounds.

By the way a 12mm socket works better than a 1/4 inch socket to hold the lower burr still.

[Randy G.]

By the way a 12mm socket works better than a 1/4 inch socket to hold the lower burr still.

I meant to say a 1/4" drive socket... Sorry for the confusion..

And there are all sorts of stupid things that people can do to screw up an espresso machine (or just about anything else for that matter). Take out the screw and use some common sense and all will be well. It is no more dangerous having that screw out of Rocky than it is to backflush your espresso machine... if they are done with common sense, all will be well.

[jesawdy]

I think the purpose of that screw is to keep one from screwing the hopper to less than '0', thus keeping the burrs from grinding against each other.

You are correct Dan. If that long screw is NOT there, and a user presses the adjustment unlock button with the motor running?

The entire top of the grinder will unscrew itself in about 1.6 seconds. (an approximate timing)

Really? It's been a long time since I used a Rocky, but a similar safety screw doesn't prevent the burrs from touching on Mazzers or Macaps. I believe its purpose is to limit the travel of the burr carrier if it binds on rocks or something, which otherwise could allow the motor to forcefully unscrew the burr carrier.

I don't think the screw will prevent the burrs touching, when you change the burr set, the screw will be in a different orientation to where the burrs are touching. I suppose that the safety aspect of the burr unwinding itself is the real answer, but I always thought it was there so that people don't have "idiot" moments and turn the scale more than one revolution and get the thing 360 degrees (or more) out of whack.

[Beavis]

How do you know when the burrs need replaced? I've had Rocky for about 3 years, grind once or twice generally for 10 seconds most days. Am I close to being in need or do these burrs last 5 + years? Where do you buy the burrs?

[Randy G.]

I don't think the screw will prevent the burrs touching, when you change the burr set, the screw will be in a different orientation to where the burrs are touching.

That is correct. New burrsets, as you stated, would change the zero point and the screw's placement is not that accurate nor is it adjustable, so it cannot be an accurate stop point.

I suppose that the safety aspect of the burr unwinding itself is the real answer....

As they say, this is what happens when lawyers are needed to assist in the design of coffee grinders sold to the masses.

....but I always thought it was there so that people don't have "idiot" moments and turn the scale more than one revolution and get the thing 360 degrees (or more) out of whack.

It happened to me once. I had done a cleaning and was setting the zero point and the hopper slipped in my hand and it spun. Although the top burr was spun around a couple of times, there was no nuclear reaction nor did the top burr fly off and hit the ceiling. Unless the Rocky is really well worn or the threads have been lubricated, the burr/hopper assembly most likely will not be ejected from the grinder. You will get a really coarse grind and quick pulls until it is readjusted.

[HB]

How do you know when the burrs need replaced? I've had Rocky for about 3 years, grind once or twice generally for 10 seconds most days. Am I close to being in need or do these burrs last 5 + years?

According to the technicians at Chris' Coffee Service, wear indicators include coffee overheating and clumping, having to grind finer and finer, shot volume decreasing before blonding and grind time increasing. I've not read an official statement of how many pounds Rocky burrs are good for, but every couple years / 75 pounds is frequently cited. BTW, if you feel the edge of new versus old burrs, the difference is not subtle.

Burrs are not expensive, I recommend replacing them (please let us know if you taste the difference). See How to know Rocky burrs are worn out? for more.

Where do you buy the burrs?

Of course I recommend one of the site sponsors listed under Commerce in the Resources page.

[jesawdy]

I've not read an official statement of how many pounds Rocky burrs are good for, but every couple years / 75 pounds is frequently cited.

I've often wondered why this is (or if in fact it is that low)... 75 lbs is not a lot considering this is the same burr set used in the the MD40, a commercial-rated grinder. I guess the Rancilio MD50 and its 64mm burrs is a much better choice for a commercial setting.