I’ve searched the forum looking for answers and noticed that others have had the same problem I did with the Barley Crusher mill cavitating.
After about 4 years of good service during frequent regular use, I encountered the same frustrating problem with the grain not feeding through properly. Opening up the gap helped the grain get started but hurt efficiency. Dis-assembly and cleaning was no help. After a close examination of the rollers, it is clear that the knurl is worn down and no longer sharp enough to catch and pull the grain through the passive roller. However, the wear is directional, the knurls are still sharp in the opposite direction! I took it apart one more time and flipped both rollers around to present the sharp knurl to the grain, now the mill works great again, only turning the shaft in the opposite direction.
I have contacted the manufacturer, they offer a lifetime warranty and will fix it at no charge. Obviously the long term solution is to send it in for warranty repair, once I get a sufficient gap in the brew schedule, I will return it for a likely roller replacement. Mean time, it’s working great running in reverse direction!
Hopefully someone experiencing the same problem will read this and find the information helpful enough to get them through a challenging brew day.
Cheers!