I am on my second DF64. I returned the first as the dial was so stiff in the espresso range that I could barely turn it. The replacement received a few days ago is stiff. Today I dialed out to a coarse grind, then struggled to get it back to espresso. I took the burr chamber apart, took out the burrs, cleaned everything, and reassembled it. It is now usable in the espresso range but stiff. I would not have bought this had I known, but this one is usable.
Does anyone know of any fixes?
This is not the threads. With the last one, I removed the spring, and the dial was very smooth. It is the spring that is the problem. It is overcompressed in the espresso range, perhaps due to too much distance between the burrs, perhaps due to a faulty spring. The burrs are marked 64 mm by 8.5 mm.
I’ve looked into shimming. However it looks like only the outer 4 mm of so of the rear of the burr is in contact with the carrier. So shim washers on the screws won’t work. It would need a high quality 64 mm wide washer.
Is there a way to reduce the resistance of the spring e.g. heat treatment? Do springs vary in which case a new one might be better?
Note added later: It has loosened off a lot now, back to how it was when first used. It is still stiffer than I’d like, a two hand job to turn, but usable. I’m wondering if the heat from grinding caused some expansion.
Note added even later: someone has pointed out that the friction between the dial and the upper burr carrier is also a factor. They inserted a teflon gasket to reduce friction which made the dial rotate more freely.