Copper Grinder vs Grindstone

Hello!
Question is simple...
When i made bonemeal in Grindstone -> +2% +3%
2% -> 5% -> 7% -> 10% -> 12% -> 15% -> ... -> 100%
is for me horrible slow
so, Copper Grinder how fast work ?
because i don't know made this tool or not... cost is BIG for me :/
Question is simple...
When i made bonemeal in Grindstone -> +2% +3%
2% -> 5% -> 7% -> 10% -> 12% -> 15% -> ... -> 100%
is for me horrible slow
so, Copper Grinder how fast work ?
because i don't know made this tool or not... cost is BIG for me :/