HB wrote:Why the rush to upgrade?
I will have to agree with Dan. I currently use a MD40, which is a beefed up version of the Rocky and believe me, you can pull very good shots with that grinder and machine setup.
Yes, you really should consider the teflon tape mod, or something along this line to stabilise the upper burr if you can detect any movement. I have done it on the MD40 which made a huge improvement.
A simple test to do to check is the burr is loose is to run the grinder empty and then find the point at which the burrs start contacting by screwing in the upper burr. From that point, back off the burr by one adjustment notch, this is your zero-not-to-exceed-point. From that point again, back off the burr by one adjustment notch, and push down on one side of the upper burr (finger push - about say 10lbs max.). The burr should contact when pressed but should not when released. Back off one more adjustment notch and repeat the side pressure. This time there should be no contact between the burrs. If there is contact, it means that there is "excessive" looseness (backlash) in the burr threads and adding teflon tape will reduce this backlash.
This is the procedure I used on the MD40. I have added teflon tape (tightly applied) until the backlash was within one adjustment notch. It is possible that the Rocky is a little more flexible and may not allow to reach that point but it is a good goal to aim at.
One thing with the teflon mod; if you move the grinder adjustment a lot you probably will need to re-apply teflon occasionally as the teflon will migrate out and the burr threads will become loose again. Unfortunately it is not a permanent fix.
Another thing to look at, is the centring of the lower burr. I have found that mine moved out of centre at one point. This reduced the quality of the grind a lot. Fixing this is as simple as loosening the burr screws and positioning the lower burr correctly. Easier said than done though. It took a lot of tinkering and patience but I ended up with something that looked visually centred. When verifying the lower burr centring, do it at a slower speed than max. Just before it stops is best. When it is spinning at max speed it will look centred but when it slows down it may show off centre. I cannot offer anything better than visual for this, but only this visual alignment improved the consistency of my grinder a lot.
After these easy modification /adjustment the MD40/Rocky is a very capable grinder and can produce very good grind for any good espresso machine.