Some grinders have a so-called THC sieve. This will allow THC residues, created by the crumbling of weed, to pass through the sieve and be collected in the lower part of the weed crumbler. This sand-like substance can be used for various purposes, such as making hash. You can also use the THC powder yourself by rolling a THC joint.
With a 4-piece grinder, the distribution from top to bottom is as follows:
Top part: moving crusher part with which you can crumble weed or other herbs by hand using rotating movements.
Second part: fixed crusher part with rotating mechanism with which the upper part goes together to crumble the weed or other herbs.
Third part: fixed collection part with rotating mechanism where the crumbled weed or other herbs can be collected after it has been crumbled by the two upper parts. This part contains a THC sieve through which THC residues can fall through and be collected by the fourth part.
Lower part: fixed collection part with rotating mechanism in which the THC remains, a sand-like substance, can be collected.