The easiest way to do a dog's nails in my opinion is to have the dog do their own nails.
It's easy! Find a board about 8-12 inches wide and 24-36 inches long. Take a look at the dog's conformation--the wider the dog, the wider the nail file needs to be. This should be comfortable for the dog to use, not difficult. Go to the hardware store and get some of the stick on tape that is used on wooden steps to make them slip-proof. It's rough, like extremely coarse sandpaper and the adhesive lasts through anything.
Cover the board with the slip-proof tape. You could also use sandpaper. The most important thing is to make sure the edges of the sandpaper are firmly glued down because otherwise the dog will peel it up. I don't know what sort of adhesive comes on the slip-proof tape but once it's stuck down on the board, it's not going to budge for anything less than extreme measures. The guy at the hardware store said if you want to remove it, you have to heat it up and use a scraper to peel it up. The stuff is meant to resist foot traffic and lasts forever. If it wore out, I think I'd just scrap the whole thing and make a new one.
You now have a giant nail file for dogs!
Teach the dog to paw the board with their front feet. If you can get a paw touch and then deliberately delay the click, you're almost certain to get a raking motion. Once the dog starts pawing on the board, most of them get very enthusiastic about it. A sizable minority alternate feet as if they were digging but it's not difficult to stop the dog that uses only one foot and get them to switch feet.
Some dogs prefer the board propped at an angle, other dogs prefer the board flat on the floor. You can put a foot on one end of the board to keep it from slipping around if it is flat on the floor. I know one person who built a little frame to support the board at a forty five degree angle but most people don't do anything that fancy. If your dog prefers the board at an angle, the easiest way is to prop it against your own knees.
So far, it's been a cinch for everyone who has tried it to get the dog to paw the board with their front feet. Every dog so far has pawed with their toes arched and foot in a sort of cup shape so that they are only touching the board with their nails.
Capturing the hind leg kick that many dogs perform after pooping and then transferring it to the board is reportedly not difficult either.
The only caution I have is to put the board away where the dog can't reach it when not in use. Everyone I've told this about who left the board out came home to find that the dog had quicked their own nails and then padded about the house, getting blood everywhere.
Oddly enough, dogs do not seem to mind quicking their own nails on the board. My theory is that the sensation builds up slowly and so is not surprising or overwhelming the way it is when the nail clippers do it. When operating the board, keep a sharp eye out and stop proceedings when the dog is getting close to quicking the nails.
Especially if the dog started out with really long nails the first few times they use the board they are likely to file the nails unevenly and at funny angles. Just keep letting the dog use the board and when the nails are short they will even out.
I got the idea years ago from a Chow breeder whose dogs strongly objected to having their nails done (a breed trait according to this breeder). She put in a concrete run down one side of her yard with the concrete brushed at right angles to the length of the pen. Each of her dogs spent half a day in there each week while the other dogs played in the yard. The penned dog would race up and down in frustration and do their own nails. I thought "there's gotta be a cheaper way to do this." Poking around the hardware store gave me the rest of the project.
I've been teaching people how to do this for over ten years and so far it's been very easy to train, even with handlers who had terrible timing.
Dogs seem to enjoy it a whole lot more than they enjoy nail trimming. As I get older, my eyesight is not improving so I'm looking for ways to make every day tasks easier.
Plus, someone on the Belg-L list related how she couldn't figure out why she got a sort of crud every other week until she realized that when she dremeled nails she was effectively aerosolizing the nail and anything the dog had on their nails. She has immune system problems but anyone can have a temporary suppression of the immune system due to stress, fatigue, illness, etc. While there is a small amount of dust flying around when the dog operates the nail file, it's nothing like what happens with a dremel.
M. Shirley Chong