I am asked this question more times then not. Many times a clipper blade is used till it becomes dull, then is thrown out.
A clipper blade is made to be sharpened again and again as many as 7-10 times. Clippers blades can be sharpened at a fraction of the cost of a new one. Small animal and large animal blades consist of 2 blades, a comb and a cutter.
If you look closely at a comb blade (large blade) you will see that their are 2 raised railes. The cutter (small blade) sets on these railes.When you have your clipper blades sharpened these rails are where the material is removed to bring your blade back to being sharp.
