I have an Anfim Best grinder. The burrs in it were still working OK and I don't think I needed new ones. But, I thought I'd get a new pair so I'd have them handy just in case I might need them in the future. I got the new pair from Espresso Parts quite a long time ago and they never quite worked out. The old pair gave decent results at position "3", which is a few notches from where the burrs touch. After installing the new pair, I had to adjust the grinder to position "1"-- a much finder setting than the old burrs needed in order to get a decent grind with most beans. With the old burrs, I could always go finer if the beans were harder than usual or I wanted an extra fine grind for some reason. But, the new burrs start to touch metal to metal as soon as I go a bit finer than my average. I tried to give the new burrs some time to "break in" or "season", but it's just not happening and I went back to my old burrs.

I'm wondering the reason for this. The measurements match. 54mm outer diameter and 8mm height. What could cause this? Maybe a defect in how the metal is cut in the new burrs? They seem useless in comparison with my older burrs. I may not need them for a long time or ever, but I'm curious about what could cause this difference.