Samples that are difficult to grind can be ground to analytical fineness by embrittlement (e.g. addition of liquid nitrogen before grinding). Under some cir-cumstances, the high efficiency of the mill can make it possible to grind such samples even with-out previous embrittlement.
The "pulverisette 14" can be fitted with a pin insert in order to grind medium-hard samples and materi-als containing oil or grease without a sieve. By inserting an impact rotor with impact blades in the sieve ring, hard to medium-hard samples can be crushed easily through the increased shearing effect.