I just installed a set of Dura-Mill burrs (from espressoparts) in an old Super Jolly I am restoring. I was expecting this grinder and these burrs to grind 18g in 7 to 10 seconds. But my grind times are only a little faster than my Mini. The new burrs take 17 seconds to grind a double. My mini takes about 19 seconds. Could this be a seasoning issue? I though that applied more to conicals than to planner burrs. What are everyone else's grind times?

Sorry to ask the obvious, but are you sure they are installed flat and flush (thorough clean before mounting the burrs) and no cross-threading when putting it all back together?

If the above is good, then it could be a seasoning issue, but if it is it shouldn't last long unless there is something wrong. A conical burrset I had almost doubled its speed with a break in of 5-10kgs.

Thanks for the reply gyro. I recently got this grinder used. It was in rough shape, so I replaced the bearings, cleaned it and threw in some new burrs. Now I'm wondering if the grinder has bigger issues. Another_jim posted a while back the burrs can come out of alignment in older grinders. His test for this is to mark one of the burrs with a black marker then transfer the ink to the other burr by letting them gently rub with the grinder running. If the ink transfers evenly then the alignment isn't my problem. I'll give this test a try and post the results. I hope that I didn't ruin all the work I've put in to this grinder by banging the new bearings into place.

You could of course change back to the old burrs and see how fast they run, might prove useful information.

They were completely covered in rust!

Is that ink transfer test safe with ceramic burrs? They might shatter into bits, no?

[EDIT] Oh, sorry, the Dura-Mill aren't ceramic.

I thought all flat burrs had... well, flat spots. Usually the maximum particle size is controlled by the distance between two parallel surfaces. So the teeth shouldn't ever interlock without horrible misalignment. At least that's the way all Mazzer burrs are.

It should be safe to lightly touch any flat burrs together while spinning.

7 to 10 seconds to grind 14 to 18 grams is typical with the Mazzer OEM burrs. I have not personally timed the grind with Duramills but hear reports that it is a few seconds faster (at most).

Hoe does the grinder sound if you turn it on with no beans in, and how does that sound compare when it is operating under load?