How poor scissor sharpening affects the sharp edge.

Previously, I have discussed the value to the hair stylist of having correct scissor sharpening for their hairdressing scissors. As in many trades, sharpness in the tools of the trade provide ease of use, less strain on the body while working, and of course allow for a more professional result. Hairdressing scissors differ from say woodworking chisels in that an edge formed by incorrect sharpening can cause irreparable harm to the future functional use of the tool. Why is this? The key lies in the characteristics of the sharp scissor edge, particularily higher end scissors, and it is this edge I would like to examine in further detail.
As we have seen before, there are two main types of scissors, bevel edge and convex edge. Bevel edge scissors are durable and effective cutting tools, suitable for dry hair cutting in particular. The bevel relates to the blunt angle formed at the cutting edge, on close examinaton, the bevelled edge, perhaps a millimetre across can be seen. Visually this can be seen below.

It is with convex edge scissors, however, that real problems arise with inexperienced sharpeners. Convex edge, as typically found on Japanese scissors, have a razor sharp edge suitable particularily for slide cutting. As can be see below, the edge tapers to a fine point, allowing an extremely sharp and smooth running edge.

The inexperienced sharpener can, however, encounter problems when dealing with convex edges. Because the edge is particularily fine, specialist equipment is needed to replicate it. On poorly sharpened convex scissors, it is common to see the smooth curve to the point replaced by a bevel, similar to the one on the bevel edge scissor. This has the combined effect of removing too much material from the scissor when the bevel is formed, and reducing the sharpness, as the angle ot the bevel is less than the angle of the convex edge. An additional problem arises from the typical equipment used in this incorrect scissor sharpening. Because this is usually done on a bench grinder, enormous heat is generated in the blade, which negatively affects the steel temper.
At Scissorfix, understanding how edges on scissors are formed allows us to service them correctly, and ensures that your scissors remain sharp for longer. This will benefit the stylist in getting the maximum longevity from your valuable tools.