Finally 5 days later, i've got a reply from PV but no reply from SCS , PV said this:
"SCS grinders use an anodizing process. Anodizing is an electrolytic passivation process use to create a strong protective coating for aluminum that limits corrosion, wear resistance, and “galling” (failing) of threaded parts. Anodizing changes the microscopic texture of the surface and changes the crystal structure of the aluminum near the surface. It not only bonds to the surface, but actually molecularly becomes the new surface. Raw aluminum is a soft material prone to even the tiniest scratches.
Eventually any aluminum grinder will show wear marks and scratches from use. They should not spin freely as the glide band will always cause resistance. All grinders must be kept clean by giving them a good cleaning by soaking in ISO otherwise resin builds up and makes it difficult to spin.
Let us know what SCS responded to you about your concerns"
So...40 bucks Grinder can scratch it and is normal, but they don't tell me the option that cannot work perfectly this Grinder? If there is some imperfection, i have no chance? Just use it like normal , im a bit confused...i think the Grinder don't work properly and i noticed cause
@Gaffa's got same problem !
I'll wait for SCS reply but i think they will not answer me , we'll see!