Regular nail files are not suitable for filing dogs' claws because they are designed for humans which are softer and thinner and the shape of human nails is curved while dogs are straighter and thicker.

It's better to go for a nail fail that's specially designed for dogs' claws to apply safety and avoid injury.

As much as it can be tempting to go for a nail file that we would use ourselves because it is usually cheaper, it's not wise to do so as they are not made to file dog claws, only human nails. 

I would advise looking for one specifically for dogs, it may be a little more expensive but will last longer and be better for your dog.