It is also important with a claw grinder sensitive blood-supplied areas of the dog's nail. If these are attacked, it really hurts and the dog starts to bleed.
Some animals have… dark claws. Here it is a little more difficult to estimate when the pain threshold has been reached. Here you have to watch the nail carefully – one is coming bright spot to appear, this means that the part supplied with blood begins. Now you should only sand the outside to round off the overall look and promote natural wear.
At bright claws It's a lot easier: If these are illuminated, you can easily locate the “lively” areas, because they then shimmer through. In all cases, to be on the safe side, you have to illuminate the claw well. One is particularly recommended Flashlight, But there are also grinders that… built-in LED light have.