Last night while doing the weekly grinder cleaning session I'm 99% sure I cross threaded the upper burr carrier into the lower burr carrier. Compared to my super jolly it's always been a struggle to thread that carrier back into place. I've owned the K10 PB for 5 months. At first I didn't touch the lube on the threads that came from the factory. I did clean the grease that all the other components had. After reading on the forums that several people had removed the lube from the threads without incidents I decided to do that as well.

Well, last night as I was threading back the upper burr carrier I heard and felt metal on metal grinding and the carrier got way tighter than normal so I stopped. I tried for several minutes to go counterclockwise to remove the carrier, but it was basically locked. I was finally able to remove the carrier, but every turn was this metal on metal grinding sound. When I looked inside the grinding chamber it was full of really small metal shavings. I glided my finger over the threads of the upper carrier and they were really rough.

From the looks of it I need to replace the upper burr carrier and probably the grinding chamber that has the other threads. Has any of you ever dealt with Compak for a situation like this?

More info:
The first time that I disassembled the upper burr carrier I removed all the lube from the tension spring. I tried to use some MOLYKOTE(food grade lube), but it didn't work. The lower half of the upper burr carrier wouldn't rotate as is supposed to. I had to use some 3-in-1 lube instead. That one is not food grade at all, and smells like gasoline, but it was the only lube that allowed the spring to glide in between the lower and upper parts of the upper burr carrier.. I have no idea what kind of lube compak used.

See Compak K10 burr installation issue

The grinding and friction probably came from the metal washer inside the adjustment mechanism, not the burr carrier threads. I can't tell you how to fix it because I haven't sorted out my grinder yet, but you might want to check it out.

Unfortunately it is the threads. The threads in the upper burr carrier are now deformed(feels like sand paper). I would always touch them during cleaning and they were pretty smooth.

Take a look anyway. It's the most likely explanation, and you don't have anything to lose. I also thought I'd cross-threaded the burr carrier threads on that K10. I spent a long time carefully cleaning it with a wooden pick, examining it for rough spots (there are many), and relubing and trying to rethread it multiple times. It behaves exactly like how you're describing, binding and grinding metal inside. The problem is caused entirely by the steel washer creating too much friction.

Is taking the grinder apart on a weekly basis a little bit of over kill?

Bob_McBob wrote:Take a look anyway. It's the most likely explanation, and you don't have anything to lose. I also thought I'd cross-threaded the burr carrier threads on that K10. I spent a long time carefully cleaning it with a wooden pick, examining it for rough spots (there are many), and relubing and trying to rethread it multiple times. It behaves exactly like how you're describing, binding and grinding metal inside. The problem is caused entirely by the steel washer creating too much friction.

I did. There is no sign of friction or metal shavings on the tension spring. That part is well lubed. I also tried to thread in only the part of the burr carrier that has the threads on it. No burrs, no spring, only the thread part and it just goes halfway in then locks. It's definitely damaged threads. I just hope that Compak takes care of me.

chipman wrote:Is taking the grinder apart on a weekly basis a little bit of over kill?

Maybe. Grindz cleans the burrs, but there is so much old coffee in the burr chamber that just cakes there and stays there.

And since it stays there, you don't have to worry about it getting into your cup.

There have been many discussions about this on H-B, and the people who I respect the most maintain that the caked coffee isn't a problem because it doesn't leave the grinder. Besides, if you remove it, another layer will replace it the next time you use the grinder and you'll be back where you started.

FWIW, I've owned my K10 WBC since June 2010 and have never opened the burr carrier.

You can try chasing the damaged threads; there's a topic on "repairing mazzer threads" here on HB. Dow 111 is kind of heavy, Superlube is food grade and a bit lighter; it makes sense to have a little lubricant on the burr carrier. Mineral oil from the pharmacy is also food grade and recommended by Ditting for food contact areas.

Peppersass wrote:FWIW, I've owned my K10 WBC since June 2010 and have never opened the burr carrier.

Might be time to take a look in there. Along with those grounds that supposedly don't come out no matter how old & decayed they get the sweepers & burr chamber surfaces do get coated with coffee oils. The grounds that definitely do come out every time you grind a dose are in contact with those coated surfaces & after 4 years I expect that those oils are getting pretty rancid.

I used to open up the burr chamber about once a week for a cleaning but these days it's more like once a month. I would hope that anyone who is regularly removing the upper carrier has removed the roll pin "stop" & is removing the carrier with the top cover attached. Without the cover on there for leverage getting the carrier out & back in is a miserable job. With it on it's almost effortless.

As the OP found out leaving the threads dry is a very bad idea. When I clean out the chamber I wipe down all surfaces with rubbing alcohol. If needed I clean out the threaded area & apply a light coat of new food safe grease. When ever I apply new grease to the threads I'll install the carrier & then remove it, wipe off any excess & then put it back in.

To repair the damaged threads the OP needs to buy a couple metric thread files. A standard file will work fine to clean up the carrier threads but he'll need an internal thread file to repair the damaged threads in the casting. If he's not up to the task any machine shop should be able to handle the job.