Clipper & Blade Issues
A short haircut should be done with a #5 blade or shorter. In grooming equipment, blade numbers go backward from what you would expect. That is, the smaller the number, the longer the hair will be, and the bigger the number, the shorter the hair will be. So short haircuts will be a #5, #7, #9, #10 (named longest to shortest). Long haircuts will be #5/8, #3, and #4, and then combs, of course, leave the hair even longer.
Blade Safety Tips
If you choose to use a #7 (FC) blade, you must be extremely careful! This blade's teeth are spaced a little too wide and folds of skin have been known to easily roll in between the teeth and cause severe gashes. Always pull the skin tight when using this blade and never run it parallel to a fold or roll. Never use this blade on the groin area or flank, on elderly dogs with thin skin, or on an animal that is dehydrated. Unfortunately, not all groomers are aware of the dangers of the #7 blade and may even refute this information as untrue. But friend, I have met too many groomers who have found out the hard way just how unforgiving this blade can be. For an inexperienced groomer, an injury with a #7 blade usually results in a trip to the vet for stitches. That is not to say that the #7 is a bad blade. It produces a fantastic short haircut for summer that doesn't look like a Marine Corps high and tight and is a favorite among groomers everywhere.
Finish-Cut and Skip-Tooth Blades
Another thing about blades that is not immediately obvious to the novice is that blades come in a finish-cut or (FC or F for short, depending on the brand) and a skip-tooth version. FC versions append an abbreviation to the number—for example, a finish-cut #5 blade would be written as #5FC or #5F. The same length of the blade in a skip-tooth version would simply be written as #5. Unless you are very experienced, you should always buy the FC type of blades