ira wrote:Do those springs take out the slop in the threads that adjust the burr?

Ira

From what I can tell, yes.

The thread slop is minimal on this design but obviously present. The design of the funnel is more like a plug with threads up top and a larger OD that fits much tighter into the upper spider than say the funnel on a Mazzer, which threads in from the top. The Ultra funnel actually threads in from below. Because of this rather unique, but simple design, there is not much "slop" in the threads, so to speak. Clearance, yes.

As for alignment, yes I've used feeler gauges and they get you quite close, but the end result is always verified by the distance between mechanical lock of the burrs and first contact. If first contact is more than about 50 microns away from full lock, odds are that you can improve the situation with shimming one of the the carrier posts. It's pretty simple in practice as you just bring the burrs to first touch and see if pressure on one of the four corners lightens the contact (sound goes away). If so, place a shim under the opposite corner and reset the zero point to check again. I was able to get between 20 and 30 microns between first touch and full lock using this method.

Pulling the mid plate and checking alignment with feeler gauges and a strong light yielded similar results, but the challenge is identifying if the tight spot is on the lower burr, upper burr or a combo of both. Using the pressure method really only addresses the top burr, but the lower burr is easily dialed in using standard instruments, so there is less to be excited about there in either case. This is equivalent to "pushing on the funnel" in other grinders, but the exposed upper carrier on Ultra makes it much more intuitive to identify which corner needs adjusted since you can influence it directly. Unlike the feeler gauge method, the pressure method can be done without concern for how true the lower burr is. Once you are at a position where pressure contact on all four corners causes the first contact sound to increase, you're done. The distance between first touch and mechanical lock then tells you the combined alignment of the entire assembled system.

Cheers!

- Jake